Here is a selection of articles from the BBC Year Books from 1931 to 1934. In the first one, from 1932, the architect of Broadcasting House discusses some of the thinking that went into the design of the building.


By the Architect, Lt.-Col. G. Val Myer, F.R.I.B.A.

Val Myer
Lt.-Col. G. Val Myer
It is imagined, in many quarters, that "modern" architecture has revolutionised the whole of present-day practice, whereas the truth is that good architecture has always been a matter of common-sense, plus a leavening of aesthetic instinct. In reality, its vital principles are no different today from those which guided the old Egyptians, Greeks, and Romans.

In planning a building, the first essential, of course, is to make it suitable for the purpose for which it is intended. That it should be pleasing to the eye is, obviously, a further necessity, but, if it looks suitable, its designer is already halfway towards achieving his object.

In the case of Broadcasting House, we had first to consider its functions. These are twofold; the actual broadcasting, and the administration of broadcasting. Obviously, the studios, Control Room, and the accommodation of technical equipment come first, with the actual studios as the most important factor of all.

Broadcasting House
Accordingly, it was the planning of the studios which had to be the key to the whole scheme. At the outset, it was thought that the ideal arrangement would be to place all the studios on one floor and, as protection against inter-studio interference, to surround each by a complete circuit of brick-built corridor. As protection against extraneous noises, the studios would be placed at the top of the building. The site of Broadcasting House, however, though picturesque in form, is irregular, which fact would have caused studios so grouped to be of awkward shape. Besides this, although the B.B.C., at that early stage, contemplated fewer studios than have now been built, the system of individual insulation by corridors and walls would have been so extravagant that the areas left for studios would have been quite inadequate. Moreover, owing to the high value of a site in the heart of London, the space available for the studios is necessarily limited. Hence the open-area system of insulation, adopted elsewhere, was out of the question.

After exploring scores of different systems of planning, the problem of accommodating a large number of studios and their suites within the space available was quite suddenly solved. Instead of the studios being all on one floor, or on two floors, they would be all in one tower, so that, given a good service of lifts, circulation would be actually easier than if they had been all on the same level, and, of course, larger and more shapely studios could be provided.

Once this key idea had been found, the plan was rapidly developed and, one after the other, its benefits appeared. The evolution of the plan proceeded on simple lines which can best be expressed as follows :-

Studios must be insulated from sound - Put a thick brick wall round them, omitting the usual steel framework.

Studios must be artificially ventilated, so need have no windows - Put them in the centre of the building, where there is least daylight to waste.

Offices must have daylight - Put them all round the outside of the building, where plenty of daylight is available.

Studios need to be sound insulated from one another - Put between them horizontal layers of rooms such as Music Libraries, Book Stores, etc., which neither create noise nor are disturbed by it.

In this way, item by item, the plans were wrestled with and were slowly developed to their present form. Sometimes, as a result of much thought, whole features had to be discarded. Such was the fate of a huge parking garage, at one time accommodated in the basement.

I could fill many pages with the history of planning this building, with all its exacting requirements, but, interesting as this would be to myself, this is, perhaps, hardly the place for such a story.

Before speaking of the exterior, I will just say a word about the internal decoration of the principal apartments. The Entrance Hall, semi-circular in plan, is simplicity itself, devoid of ornament, and depends for its effect upon the grace of the natural curves which arise from its circular form and the rhythm of its vertical lines. The beauty of the English marble (Hopton-Wood stone), which lines the walls, is an added charm. The central feature of the Hall is to be a lovely figure of "The Sower," for which Eric Gill has already made his model.

The Council Chamber, sixty feet across, is of semi-circular shape, like the Entrance Hall. This room, whose acoustic qualities are strangely happy to the naked ear, is lined with Tasmanian oak and, at night, is entirely illuminated by reflected light from lamps concealed in wrought oak urns. The pedestals of these urns serve as relieving accents of interest to the simple panelled walls.

The Concert Hall, in the heart of the building, is wedge shaped in plan. The splay is not sufficient for one to realise, at first sight, its existence, but it has the strange perspective effect of making the Hall appear very much longer from the back than from the stage.

Model of the Conert Hall
As will be seen from the photograph of the preliminary model of this Hall, the treatment of the ceiling is entirely novel; it is hoped that, with the semi-indirect lighting indicated, the ceiling will provide a very distinctive feature.

At the time of writing, this Hall is being finished in the rough for my scientific colleagues to test its acoustic qualities, and it is only after we have their results that a decision will be made as to the actual materials with which the design will be clothed.

East side showing sloping roof
Now, a word as to the exterior, First, let me explain the reason for the eastern side being cut away as with a drawknife. This part of Langham Street is narrow and, not only have the opposite owners rights of light which had to be respected, but there are three-sided mutual covenants with other neighbours which could not be broken. Hence, the whole of the building above the fourth floor had to be sloped back and restrained within a limiting angle.

In Portland Place, the only limit of height was that imposed by the London Building Act.

The south end of the building, facing down Regent Street, suffered under the same difficulties as the Langham Street front, but at this vital point, realising my troubles, the parties concerned made certain concessions of real value.

In the circumstances, the obvious course seemed to be to design a symmetrical facade to Portland Place which would dominate the whole building, to emphasise the main doorway facing south by placing a Clock Tower above it, and to be satisfied with a modest elevation to Langham Street which, without being striking, would be suitable.

The marrying together of these three components was a particularly interesting problem, which was helped by the provision of a third aerial mast over the Clock Tower.

At an early date I realised that the site possessed a rare virtue in the long curve of the western side, and so, in organising the proportion of my masses and the play of light and shade, I tried to make full use of the gracious horizontal lines which this curve suggested.

Broadcasting House is said to look bigger than its actual dimensions. This is due to the scale and number of the windows, necessitated by the provision of an immense number of small offices. Endless flexibility of subdivision of offices was required by the Corporation, which fact, naturally, weighed with me in preparing my design for the façade.

Although economy was essential to the whole scheme, and the sculpture at my disposal limited, I insisted that it be as good as possible, and then placed it, with other architectural features, at the most effective points, hoping to set it off to advantage by the contrast of plain walling and the considered rhythm of the windows referred to above.

Before concluding, I must pay tribute to the courtesy and extraordinary ability of Mr. M. T. Tudsbery, Civil Engineer to the B.B.C., who has been associated with me in the work for nearly four years. Another debt of gratitude is due for the many excellent suggestions which I have received from Dr. M. J. Rendall in matters of artistic taste.

From the 1931 Year Book STUDIO ACOUSTICS

Probably the most important property of any room or hall used for listening to speech or music, whether through the medium of broadcasting or not, is what is termed the reverberation time. To recapitulate briefly, if in any ordinary room a source of sound (such as a musical instrument which has been playing a sustained note) suddenly ceases, the sound is still heard for a short period, the duration of which will depend on the amount of sound absorbing material in the room. The time in seconds taken for a fairly loud sound to die away to inaudibility under these conditions is called the reverberation time, and is a definite property associated with the room. In more scientific language, it is the time taken for the average sound intensity in the room to die away to one millionth part of its initial value.

Now it has been found by experience that for a room of any particular size, the reverberation time must have a definite value in order that music may be heard and appreciated at its best. For a fairly large studio such as is used by the B.B.C. for performances by an orchestra of medium size, the required reverberation time is about one second. For a small studio, used for solo items, for combinations of a few instruments, or for talks, the required value is still less, whilst for the largest studios, or for concert halls used for broadcasting, it may be two seconds or even more.

That some limitation of the reverberation period of a studio is necessary was recognised from the early days of broadcasting, when the normal treatment was to introduce into the studio a large quantity of drapings or curtains, with which the walls were covered. Sometimes as many as five or six layers of curtains were used.

Such treatment was far from satisfactory for several reasons. First, it was found that no matter what quantity of curtains were used, a really pleasing reproduction of music could not be attained. If too little draping were employed the result was "echoey" and unpleasing, whilst as the quantity of deadening material was increased the result became dull and lifeless with none of the brilliancy which would be a normal feature of the performance. The psychological effect on artists was very similar. They found difficulty in performing in the early studios, by reason of both the deadness to the ear and the depressing effect to the eye, for a heavily draped studio does not lend itself to pleasing decorative treatment.

The reason for these difficulties is now apparent, for it has been found necessary to take considerable account of the variation of reverberation time with pitch or frequency. The earlier measurements of reverberation time, whether in connection with broadcasting or undertaken in the study of architectural acoustics, were almost always made at a frequency of 512 cycles per second, corresponding with a pitch of one octave above middle C. It is necessary, however, in order to determine the acoustic behaviour of any room or studio, to make determinations of the reverberation time at various pitches or frequencies, and so obtain a reverberation-frequency characteristic, showing the value of the reverberation time throughout the musical scale.

Figure 1
According to present-day ideas, in order that the reproduction of music from a studio shall be pleasing and musically satisfying, the reverberation time must be practically independent of pitch, and must possess the value already indicated. A curtained studio, however, is very far from satisfying these conditions. Fig. 1 shows the reverberation-frequency curve for a comparatively lightly draped studio of such a type. It will be observed that the absorption of sound, as indicated by the shortness of reverberation time, is much greater at the high frequencies than at the low. This accounts at once for the lack of brilliancy of broadcasts from such a studio, and for the "boomy" sensation experienced on entering it, which is mainly responsible for the depressing feeling of "deadness" complained of by artists.

Any increase in the quantity of draping material would only reduce still further the reverberation at high frequencies, whilst making little change at the low. If indeed, by the use of an exceptionally large quantity of draping, the low-frequency reverberation were reduced to the desired value, the studio would be practically without reverberation at the higher frequencies. This was, in fact, the condition of the first studios used in broadcasting.

The problem of providing studios possessing a suitable reverberation time, independent of frequency, really resolves itself into that of finding sound-absorbing materials which are equally effective at all frequencies, and which are at the same time susceptible to decorative treatment without the destruction of their acoustic properties. The general requirements of such a material will be realised when it is understood that the sound waves at the higher frequencies seem to be absorbed in the pores of the material itself, losing their energy by multiple reflections from side to side of the minute apertures which form a large part of the surface of a porous substance. The sound waves of the lower frequencies, however, are apparently most readily absorbed when the whole surface of the wall is capable of yielding under the variations of pressure exerted upon it by the sound waves.

A compressible porous material is therefore required for the successful treatment of a studio. Ordinary hair felt, if of loose texture and of sufficient thickness, fulfils these conditions fairly well, and has been used to a considerable extent in the treatment of B.B.C. studios in the last few years. The chief difficulty in the use of felt, in common with that of many other possible materials, is that of providing suitable decorative treatment. One method of decoration has been to cover the surface of the felt with a loose-textured wall-paper. This, however, destroys the porosity of the felt, and very considerably reduces its absorptive properties at the higher frequencies, producing unduly long reverberation at those frequencies,
Figure 2
particularly when, as has not infrequently been the case, the decorative treatment has demanded the painting or distempering of the surface of the wallpaper. The effects of such treatment are shown in Fig. 2, by the full line, which represents the variation of reverberation time with frequency of a medium-sized studio treated with felt and decorated with distempered wallpaper. The practical and easily observed effect of a reverberation-frequency curve of this type is that the studio exhibits a very pronounced "chink" or buzz for simple percussive sounds such as the clapping of hands. In the case in point the buzz, which is due to multiple reflection of the sound waves backwards and forwards between the walls of the room, was sufficiently pronounced to be readily audible during speech and certain kinds of music, particularly piano music.

Fortunately a fairly simple corrective treatment can be applied by making use of the fact that light curtains are most absorptive for the highest frequencies. It is possible to calculate, data being available regarding the properties of the curtains, exactly what area of wall surface must be curtained in order to produce the best effect. In the particular case under consideration the covering by light curtains, hanging in loose folds, of nearly one-third of the total wall surface resulted in the curve shown by the dotted line of Fig. 2. The undesirable buzz was found to have entirely disappeared as the result of the treatment and the studio to be very suitable for broadcast transmission.

A more suitable material for studio treatment would, however, appear to be felt with a decorative treatment of some fabric such as tapestry or fine canvas, preferably stretched over the surface of the felt. Such treatment is being tried in the construction of new studios, whilst at the same time a thorough investigation of new materials and methods of treatment for use in the future is being made.

It is hoped that in due course it will be possible so to construct studios that the use of artificial echo, as at present employed, will be avoided. There seems no inherent reason why it should not be possible to modify the acoustics of the larger studios so as to produce an effect similar to that of the most popular of the outside concert halls and other buildings from which broadcasting is conducted.


The general question of the design of studios for broadcasting, and the nature of the technical problems involved, were fully discussed in the issue of the Year Book for 1931 (see above). It is unnecessary, therefore, to deal again with the whole of the theoretical side of the question, and it is proposed to confine the present article to a discussion of the application of the general principles to the particular problem of the design of studios for Broadcasting House.

Readers may remember the statement made in the article referred to above, that the most fundamental property of a studio, which largely determines its suitability or otherwise for broadcasting, or even for direct listening, is its "reverberation time," and the dependence of that property on frequency or pitch. The reverberation time is the time, expressed in seconds, taken for a fairly loud sound of the frequency concerned to die away to inaudibility after the source has ceased to operate. Defined in scientific terms, it is the time taken for the mean sound intensity in the room to decay by 60 decibels, that is to say, to one millionth of its original value. It is quite definitely related to the volume of the room and the amount of sound-absorbing material which the latter contains, and simple mathematical expressions have been derived whereby it may be calculated, with reasonable certainty, in advance of construction.

Experience has shown that so far as studios to be used for musical performances or for general purposes are concerned, the desirable reverberation time does not differ greatly from that which would give the best conditions in a room of the same size intended to be used as a music room or small concert hall with no reference whatever to broadcasting. It must be understood that if the reverberation time of a given room is too high, the result sounds "echoey," all definition is lost in music, and speech becomes very difficult to understand. If, on the other hand, it is too low, music is clear and distinct, but the effect is dull and lifeless, and reminiscent of that obtained in the open air. The determination of the actual value of reverberation time which will give the desired mean between these two extremes can only be made by making measurements of the reverberation time in halls and rooms which critical musicians consider to be acoustically good. It is necessary to realise that whilst scientific methods may be employed in the design of a room so that it may have certain characteristics, the decision as to what those characteristics should be must remain largely a matter of experience and musical opinion. Such measurements have been made by various authorities, and the optimum reverberation time of a given room is found to depend on its volume. The larger the room is, the longer must its reverberation time be for the best conditions.

In designing the studios for Broadcasting House the optimum reverberation time has been taken to be slightly less than would be the case if the studios were to be used for direct listening, without the medium of the microphone. There are two reasons why the accepted time for direct listening has been somewhat decreased. The first is, that in listening by means of a loud-speaker, the reverberation time of the listener's room has to be taken into consideration, being virtually added, so far as the final effect is concerned, to that of the studio. The second is that broadcast listening is effected with the aid of a single microphone, and is therefore the equivalent of monaural listening. For some psychological reason, not fully explained, the effect of reverberation is more noticeable in monaural than in binaural listening, on the basis of which the accepted values of optimum reverberation time were determined.

As concrete examples of the reverberation time for which various studios are being designed, the large studio or Concert Hall, which has a volume of very nearly 150,000 cu. ft., is to have a reverberation time of 2 seconds; the Vaudeville Studio, 3,000 cu. ft. in volume, is to be of 1.3 seconds period, whilst a small Debates Studio is being constructed to have 0.6 second reverberation, corresponding with a volume of 2,200 cu. ft.

As has been already indicated, the variation in reverberation time which takes place with frequency or pitch is of the utmost importance, and the Broadcasting House Studios are being constructed, as far as possible, to possess reverberation independent of pitch. This means that the rate at which the sound energy in the studio dies away is the same for all notes within the musical scale. Where it is not possible to fulfil this condition exactly, the reverberation time is allowed to decrease somewhat towards the higher or treble frequencies, the maximum reverberation time being that which is determined from accepted data as described above. No marked increase in reverberation time for any part of the frequency scale is, however, to be tolerated.

A certain school of thought in acoustical work considers, on theoretical grounds, that the reverberation time of a good auditorium should be very definitely greater for the lower frequencies than for the remainder of the scale. There is room for considerable difference of opinion in this respect, but even if the suggestion is true under certain circumstances, such conditions may be dangerous for broadcasting on account of the difficulties of "bass blasting" which occur as the result of excessive reverberation at the lower frequencies. Still less can any increase in reverberation towards the higher frequencies be allowed. Should this occur, reproduction is characterised by a marked "edge" and excessive brilliance, which is most unacceptable to musical taste.

In a concert hall of the ordinary type, a very large part of the sound absorption which limits the reverberation time is due to the audience itself, and this constitutes a very serious difficulty in the design of such buildings to satisfy acoustical requirements, since an audience represents a variable quantity, and consequently the best the designer can do is to compromise in the matter of reverberation time, making his conditions right when only a part of the full audience is present. In broadcasting studios this difficulty does not arise, to so great an extent, but it now becomes necessary to discover materials with which to treat the greater part of the wall surface to provide the necessary absorption. Clearly if the reverberation time of the completed studio is to be practically independent of frequency, the same must apply to the absorptive properties of the sound-absorbing materials. At the same time these materials must be susceptible to a certain amount of decorative treatment without losing their acoustic properties. Two types of material are being specified for the majority of studios in Broadcasting House. Of these, one is ordinary "building board" or "insulation board," composed of wood pulp, cane fibre or similar material, and the other is a treatment which has found a certain amount of use in B.B.C. studio construction in the past, namely, "felt and wall-paper treatment" consisting of a layer of I in. hair felt applied to the wall surface and covered with one or more thicknesses of lining paper and a soft porous type of wall-paper for decorative purposes. Both of these materials, if certain precautions are taken, possess absorptive properties sensibly independent of frequency. Both must be stuck firmly in contact with a rigid wall surface, and not supported on battens out of contact with the wall. Neither must be subjected to decoration involving any form of paint or distemper which will alter the characteristics of the surface of the material. Colouring by means of stains or water-colours is, however, permitted, whilst an alternative method is to stretch very thin decorative fabrics over the surface of the sound-absorbing material.

Whilst the majority of the studios in Broadcasting House are being acoustically treated in accordance with the principles outlined above, several, to be used for talks and dramatic effects, are being made acoustically "dead." This means that their reverberation time is to be made as small as possible by covering the walls and ceiling with a material which absorbs a very large proportion of the sound energy reaching it. The material which is employed is known as "Rock Wool." It is composed of a mass of vitreous fibres and is applied between battens to the wall surface to a thickness of several inches.

The reason for the adoption of this treatment in the case of talks studios is that it is plainly desirable for the listener using a loud-speaker to get the impression that the speaker is addressing him in his own room, whether the latter happens to be large or small. If this is to be the case, the sound of the voice must be modified only by the acoustics of the listener's room and not by any effect emanating from the studio. Hence the studio is so treated that as little reflected sound as possible reaches the microphone. In the case of the dramatic effects, varying degrees of reverberation are necessary for different purposes, and these are obtained by adding "artificial reverberation" by the use of a so-called "echo room" to any desired extent, as described in the B.B.C. Year-Book on previous occasions. Here again, therefore, the studio itself must possess the property of reverberation to as small a degree as possible.

From the 1933 Year Book, but originally published in The Listener of 13th July, 1932. THE ARCHITECTURE

By Professor C. H. REILLY
Professor of Architecture in the University of Liverpool.

Broadcasting House
The south front and main entrance of Broadcasting House in the shadow of All Souls church.
One obviously cannot get very far in appreciating any building until one knows not only vaguely the purpose of the building, but something definite about the programme to which the architect had to work in making his design. Without this knowledge one can merely judge his creation as one sees it in the street, an ornament or otherwise to its surroundings or, if important enough, to the town as a whole. In these days of transition, however, even that is a little difficult. An ornament implies something ornamented and the ornament as part of a scheme of decoration. The point at once arises as to whether the building in question is to be considered as part of the scheme of decoration of the street as it stands at present and to be judged accordingly, or as part of some future scheme. If the latter we are in obvious difficulties. The most we can really expect in a new building, such as that of the B.B.C., placed in an area where in the past there has been a very powerful scheme, but where no new scheme is as yet in existence, is a certain neighbourliness which will make the building consort fairly well with both its present neighbours and its new ones when they arise. This, if important, is admittedly a little vague. We will return to it later. It points, however, once more to the special need to-day (when the traditional ways both of building and of expressing ourselves in our buildings are changing, and rightly changing, in sympathy with our different ways of living), of understanding the programme put before the architect by the promoters. As part of that programme one must realise, what is not always easy to do in a town, the shape of the site and the restrictions it has placed on the designer by its outline and by any rights of lights over it of neighbouring property.

The programme in this case was a unique and inspiring one, a problem indeed to fire the imagination of the architect and everyone else concerned. The main portion of it, in impressiveness, if not in required cubic contents, was the provision of a mass of insulated concert halls and studios, from which music and messages of every kind would be sent out world-wide, and that not as the effort of private enterprise as in some other countries, but as representing the nation. That, at any rate, is how that part of the programme would appeal to the architect, seeking, as he must always do, to give the noblest possible expression to his client's building. Subsidiary to this central function of the new building, but actually occupying a great deal more floor space, was ordinary office accommodation for the six hundred odd persons in one way or another organising this new and exciting public service. Such office space, of course, like nearly everything else, is capable of fine architectural expression, but it will be admitted at once that it does not offer a new or unusual programme. It is indeed the programme which most of the buildings in the central areas of all large towns are designed to answer. This office accommodation, therefore, should not be permitted, if the site were sufficiently large, to overwhelm the more distinctive portion of the building. That it has not entirely done so in the new B.B.C. building is a great tribute to the architect, Colonel G. Val Myer. In spite of having to wrap his studio block completely round with offices, so that externally the most distinctive portion of his structure does not show at all except for the short length of plain walling with seven small roundels in it at the top of the Portland Place front and the three small steel receiving aerials on the roof, he has certainly managed to give to his building a different air from that of the ordinary office block, and to suggest that it serves some new purpose. His building does not look, fortunately, like an ordinary Government office, nor an ordinary block of offices; nor a hotel. One is arrested by it and certainly, if one did not know, would ask what it was. We will leave it at that for the moment.

Let us return to the part of the programme involved in the site. It is an oddly shaped site rather like a lopsided potato or sausage balloon tapering to a roughly rounded nose facing down Regent Street, with a long bulging side to Portland Place and a straight one to the back street. At the end opposite the rounded nose the site is cut off sheer by the adjacent property. Its length is about 200 and its width in the middle is about 120 feet. It is very significant, both of the amount of accommodation the architect had to fit on to this site and of his consequent difficulties in properly articulating and expressing its various functions, that he has had to fill the site completely from end to end and side to side, save for a small area for neighbourly accommodation at the truncated end. He has not been able to allow himself any of the ordinary lighting courts a building of this width would call for. Except for his external layer of offices, therefore, his building has had to be lighted and ventilated artificially, and very well it has been done. To get everything in he has had, in addition, to carry his building up everywhere to the full height the London Building Act permits. If one had to fill a sack entirely full with any substance, one would obviously have considerable difficulty in arranging in addition expressive folds in the sacking, if that were one's object too, as it must always be with the architect.

A further difficulty of this site was that it was commanded by rights of light by the buildings in the back street. This is the reason why the end of the new building looking down Regent Street is so unbalanced at the top. One side has been sheered off as it were by the windows in the buildings opposite. How the directors of this great enterprise, with a future no one can foretell, but one certainly of increasing not decreasing activity, came to choose such a site it is a little difficult - for an outsider like myself to understand. One would have thought that they would have made every effort to have obtained a free open site instead of a restricted street one, a site, that is to say, where their building could have expanded upwards and outwards, as best suited its peculiar character. No doubt in the central position required it would be difficult to find such a site, though one nearby at once jumps to the eye for so unique an occasion.

It is the site which used to be suggested for that unfortunate ghost of a dream the National Theatre, a site in Regent's Park itself facing directly down the great avenue of Portland Place, the widest street in London. There the big block of concert halls and studios, windowless, but all the more significant for that, might have grown into a great dominating central tower round which, at appropriately lower levels, could have been grouped the office accommodation in proper subsidiary relationship. It would be difficult for an architect to imagine to-day a more thrilling programme than for such a building on such a site. One does not, of course, want to see the parks encroached upon for any ordinary purpose, but if Hyde Park could admit the Albert Memorial, Regent's Park might well have provided on its edge a worthy position for so striking a form of modern expression as a great broadcasting building for the metropolis.

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The architect has naturally made his main entrance at the rounded nose facing down Regent Street. Entering there you are at once in a fine spacious semicircular hall with lifts and doorways opposite you. The semicircle is defined by a range of strong piers with space behind on one side for a counter. This space is where the site with its odd potato-like outline overlaps the semicircle, and shows that in the interior here the architect has very ably turned his difficulties to account. The outside, of course, had to follow the outline of the potato. With land of enormous value per square foot architecture has, as things are to-day, to take a humble place. However, in the interior of this entrance hall, where the architect was able by his device of a semicircle of piers to free himself, the architecture is strong, simple and modern in the sense that it does not rely on traditional motives for its appeal.

Immediately behind this entrance hall is the great central core of the building, following the outline of the site and surrounded from top to bottom by a thick wall. This is the central studio block, and once the artists have passed into it from the entrance hall they cross no administrative portion of the building. Their cloak rooms, rest rooms, refreshment rooms and lavatories and, of course, all their studios and concert halls, are within it, artificially lit and ventilated. In persuading the authorities to allow artificially ventilated retiring rooms the architect has, it may be hoped, achieved a very valuable precedent which will in future permit such rooms to be placed in the dark portions of the plan instead of against external walls only, an economy of space and light long since practised in America. When the artists have finished their work they pass out the same way. If, however, instead of going through the central doors for the artists one goes to the right or to the left or takes the corresponding stairs or lifts, one enters, at any floor, the long office corridor which completely encircles the studio block. This corridor serves the layer of offices one room thick which everywhere occupies the external face of the building.

The offices need not detain us. They are straightforward well-lit rooms, neither too high nor too low, without ornament but with an air of efficiency which one expects to-day but which was hardly to be found five years ago. Occasionally there is a suite of rooms for a director or sub-director and these have simple panelling. There is a board room treated in the same way, fortunately free from the loops of carved fruit and flowers our bankers still require for complete happiness. Above the entrance hall there is a fine circular conference hall, a little more strongly modelled but still retaining the air of efficiency which is the keynote of the interior.

We now come to the buried studio block in the centre of the structure, the holy of holies, the mysterious heart to which I am sure the architect would have liked to have given fuller expression on the exterior had his site allowed him. The decoration of these studios being the subject of another article, I must only refer to them very briefly. Lowest of all in the second basement, but above the heating and ventilating machinery, is the vaudeville studio, but, nevertheless, with a small gallery for auditors, and with stands for spot-lights; without either of which, even when broadcasting, one may suppose a vaudeville artist would feel abashed and awkward. It seems appropriate that the centre of laughter should be deep in the bowels of the earth.

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On the next floor up, but still one down from the street, is the big orchestral Concert Hall, the third biggest concert hall, I am told, in London. On the floor and in the gallery 550 of the public will be able to hear the concerts, approaching the hall by stairs and a special entrance, very well managed, from Portland Place. This hall is the finest thing in the building. It is strongly modelled with great bracketed beams to break up the sound. Without reliance on traditional forms it yet has great scale and power. There is indeed something cyclopean about it which provides a suitably serious air, and at once separates it from the ordinary run of frivolous apartments in which English people are, as a rule, compelled to listen to music. Yet with all this it does not lack interest. That is given largely by the lighting, the tapering shape and the heavy crouching balcony. Altogether it is such a hall as Piranesi might have designed had he dreamed of such instead of prisons.

The other studios do not come within the scope of this article, but up above
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them all is the control room which to me, with its switchboards and strange, clean, clear-cut instruments under a perspective of sloping beams, is the most decorative of all. The little mixing room at the same level where the sound from all the studios can be mixed together, if not susceptible to much architectural expression, calls up an irresistible desire to return to the mischievous days of one's youth.

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To come at last to the exterior, one sees that the architect has taken the big curved front to Portland Place and modelled it in a series of flat vertical planes rising sheer from the pavement but balanced about a central axis. The windows in their long ranges emphasise admirably the curve of the front. Probably out of sympathy for the surrounding buildings, he has not turned them into long continuous sheets of glass in the logical modern way, but has given each the ordinary vertical shape. He has even filled them with bars, in these days of plate glass, to obtain a contrasting texture with his plain stone surfaces. These great stone cliffs of his, rising as it were one behind the other from a base modulated by a range of larger windows, a band of wave ornament, and a central strongly marked balcony, but with no crowning cornice, give an aspiring look to the building well in keeping with its central function.

Such ornament as there is, the decorative coat of arms and the interesting frieze of birds and rays of light on the balcony front, designed by the architect, and the impressive reliefs by Mr. Eric Gill at the base of the two bays flanking the Portland Place front are, like the building itself, restrained and forceful. Mr. Gill is to fill the great niche over the entrance door with a bronze group and it is not fair to judge this front until this is in place. As already pointed out, this front can never be symmetrical owing to the exigencies of the site. Its overloading on one side like a naval aircraft carrier is probably the reason why the building has been likened so often to a ship sailing down Regent Street. If, however, one mentally restores the missing blocks of building one sees at once that this front, if not so placid and dignified as the great curved one, would, nevertheless, come to rest as a stable and solid monument. In an age of transition then, on a difficult and restricted site, and with the most interesting things in his building necessarily hidden, one can congratulate the architect on a very notable achievement. One is a little less certain about congratulating the B.B.C. who set him the problem.

This article from the 1933 Year Book has been quoted from on the pages dealing with the studios but is here reproduced complete. THE DECORATION OF THE STUDIOS

By Lord Gerald Wellesley, F.R.I.B.A.

The interior of Broadcasting House is the most important example of untraditional decoration yet completed in this country. The accumulated rubbish or wisdom of the ages has been washed away, and something which is definitely and entirely new has taken its place. Such a phenomenon has never occurred before in the world's history. Taste in building and the trappings of life generally has always been in a state of flux and change, but its evolution has hitherto been gradual, even when enforced by political upheavals. It is therefore natural to wonder why in our time we have not been able to make a complete success of a gradual evolution and adaptation of traditional forms to modern conditions. The Swedes can do it, and to some extent so can the Austrians; but in England such attempts, at any rate in vast town buildings, seem poor anæmic affairs sadly timid compared with honest, stark, functionalism.

Nevertheless, though tempered traditionalism may be unexciting, it is in many instances justifiable and can in no circumstances arouse the disgust and ridicule which profuse untraditional and newly-invented ornament causes. How pathetically old-fashioned is the immensely elaborate carved wooden room set up during the first years of the present century in the Musée des Arts Décoratifs in Paris. Will the future ever produce a defender of the luxuriant decorative orgies of that manner which we used to call "the Art Nouveau" and the French "le modern style"? The epoch will, of course, in time find admirers among those who have a great "sense of period." But surely no one will ever want to live in an elaborate "modern" room of the year 1902. The fallacy that you can invent architectural ornament was not dead in the year 1925 when the great Exhibition of Decorative Art was held in Paris. The buildings and rooms bristled with rows of silly flutes and yards of zigzags, which lacked the great traditions of the egg and dart or the Greek fret and were every bit as meaningless. To lay down any law in the realm of aesthetics is difficult, but a strong case can be made out for the proposition that something really new happened in architecture and decoration when it was realised that you cannot invent your own architectural ornament. You must either use what has come down to you through the ages or else do without.

Now I do not mean by this that no concession to the pleasures of the eye should be made in a modem building. All sorts of things to please the eye can be done without resorting to sinkings and projections. In the first place there is no reason why sculpture should not be used. Let there be no nonsense about the sculpture being part of the construction of the building. It is there purely to adorn it precisely as a room is adorned by a picture or a vase of flowers. When it comes to the inside of a building the possibilities of embellishment possessed by the architect are almost as great as those of an eighteenth-century predecessor. Of course he must not resort to a cornice, or moulded door architraves or skirtings or panelling or a great carved and moulded fireplace forming a climax to a room like the altar to a church. But in revenge he can make all this seem fussy and commonplace in contrast with the clean simplicity of his lines, with the subtle harmonies in colour, which the complete absence of projecting decoration seems to indicate. But above all he can do anything he likes with his lighting. He can toss it from surface to surface, he can throw it up and down. He can diffuse it if he wishes or he can concentrate it to emphasise some feature of his room. It is his slave, as water was the slave of the baroque garden architect. This god-like power to bend light to the will of man, which is the greatest advantage that the designer of to-day has over his predecessors, is peculiarly important at Broadcasting House as, with one exception, the studios, for acoustical reasons, are all embedded in the centre of the building and are never lit by the crude untamable sun.

Another fundamental difference between the room of the past and the truly modem room is the importance which the few decorative objects which are allowed to enter it assume. A Georgian or Victorian room may well contain thirty articles the sole function of which is to adorn. They are, in fact, what old fashioned housemaids call "ornaments." The modern room contains two or three. One vase filled with flowers, real or artificial, one picture and one statuette on a table - a bare three ornamental objects form quite a liberal allowance for a new room. But then how interesting each becomes. A tall vase with two lilies, placed in a niche and lit from below, is far more arresting than a table covered with fifteen full flower vases which have taken half an hour to arrange. This Japanese economy in objects the sole function of which is to embellish is of the very essence of modernity. The thrill that a vase of flowers or a cactus gives in the setting of a modern room is unexpected and difficult to analyse. It is like a living, articulate, voice in a well of silence. It is the one note which breaks the repose, the one place where rowdy colour flashes and exuberant forms are allowed. Place the same vase on a table in some old-fashioned drawing-room and it would not be noticed. The use of flowers and plants in Broadcasting House is masterly and in many cases forms an essential element in the decorative scheme.

The designers of the studios have in no case had a free hand. They have always had to conform to given proportions of reverberating and non-reverberating substance on their walls. These proportions vary in the different studios. The materials most used are "Donnacona" or "Tentest" wall-boards, made in large sizes and having a rough texture, hard synthetic resin sheets, plywood, and various stuffs. Except the rough wall boards these materials may be of any colour. Although the use of given proportions of these materials as wall coverings meant a strict limitation to the designer's fancy, the mere fact that so much was decided for him was probably a help. A severer limitation was the ban on all foreign imports. Many of the substances used had therefore to be made in England for the first time. Moreover, there is practically no room in Broadcasting House which is a plain rectangle; but this would have been a severer handicap to designers on traditional lines, as would also the rows of small upright apertures demanded by the very efficient ventilating system.

It may be asked why so much care should be lavished on the finish of the studios which are only seen by the broadcasters. Why is more required than, for instance, the standard of finish to be found behind the scenes in a theatre? To such utilitarian questions the reply is that the atmosphere of a broadcaster's surroundings affects his performance. Bright bands demand bright rooms: talkers want intimate little studies: religious performances must take place in a temple-like structure elaborately unsectarian, and plays and sketches must be staged in something resembling a theatre.

The resolution of these difficult and delicate problems was entrusted to different designers whose work we will now examine in detail. Lieut.-Colonel G. Val Myer, the architect of the whole building, retained the large Concert Hall in his hands. Most of the other studios were designed by Mr. Raymond McGrath, Mr. Serge Chermayeff, or Mr. Wells Coates, whose works and tastes are on similar lines. A small talks studio in a traditional manner was entrusted to Mrs. Dorothy Warren Trotter and the "Temple to an Unknown God" to Mr. Edward Maufe, who has recently won the competition for Guildford Cathedral.

Far the largest of these apartments is the Concert Hall, for it will accommodate a large though not a full-sized orchestra and an audience of 550. Colonel Myer has made great play in this room with changes of plane. Practically 'the whole of the wall surface is carried out in plaster, and for this reason, no doubt, acoustical considerations imposed what seems, by comparison with the other interiors, a great elaboration of detail. Sinkings and projections, coffers and corbels, produce strong contrasts of light and shade and give variety and incident to the hall. No attempt is made here to diffuse light. The aim has been to make certain planes stand out in blinding whiteness against the pools of shadow. The general effect will be felt by some people to be exciting, by others restless. No doubt when filled with orchestra and audience the "busy-ness" of the plaster-work will count for much less than it does when the room is empty.

Mr. Maufe had a difficult task set him when he was told to create a temple where Catholic and Calvinist, Jew and Moslem, should feel equally at home. At the "East" end of the "chapel" are three arches of equal height. The two side ones frame two small doors, while the central space is filled with a brilliantly lit back-cloth of palest blue, above a substitute altar. The colour is very happy. The green columns stand out against the pinks of the wall and floor. The ceiling is blue spangled with gold. The four capitals have an Ionic flavour.

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As a concession to the conservatism and weakness of human nature, it was decided by the authorities that one of the talks studios should be definitely traditional in flavour. It was feared That elderly dons and clergymen, so far from being stimulated and put at their best by the naked simplicity of functionalism and metal furniture, would be definitely frightened of it. So a little library with every sham which could be crowded into so small a space was devised for their comfort. The pretty little room, designed by Mrs. Dorothy Warren Trotter, receives light from a large artificial window draped with curtains festooned in the true Regency style. The chief decoration of the walls is provided by book-cases filled with the loveliest book-backs gummed on to the plaster. There is a mantelpiece marbled to look like verde antico, but no fire can burn in it as it is not provided with a chimney. Over the mantelpiece a portrait of George Washington, the man who never told a lie, surveys the room with dignified hauteur. It would be absurdly puritanical to quarrel with these innocent deceptions. The room fulfils the conditions imposed on the designer. It is "cosy," an epithet which could not possibly be applied to the other studios. Figuratively speaking a perfume of pot pourri and old leather bindings hangs about it. Figuratively, I say, for were it possible to discharge such an emanation into the room, the magnificent ventilating plant would make short work of it. The furniture is good, solid and English. In fact there is nothing to offend the senses of the most cloistered recluse that ever came out of a country deanery, and that is an achievement of which Mrs. Trotter has every right to be proud.

And now we come to the really exciting rooms in Broadcasting House, rooms in which what matters is not the avoiding of giving offence, but the more active and noble effort to design something which is supremely fitted to its purpose, which stimulates the user, something alive, brave, and new.

The work of the three remaining designers, Mr. Raymond McGrath, Mr. Wells Coates and Mr. Serge Chermayeff is similar in aim. It is, to use a modern cliché, functional. I have never seen a definition of functionalism, but it may be said that its aim is supreme fitness for purpose and the elimination of all material which can be dispensed with. It may be contended that this is not a definition of out-and-out functionalism which is simply the degree of decoration of a factory, but it will do for the B.B.C. studios. It will be noticed that the definition says nothing about superfluous labour. To make my meaning clear let us take a rug, which is a necessity in a talks studio. The rug is made partly of dark brown wool and partly of buff wool. As presumably wools of either colour are identical except in tint you add no superfluity to the rug by putting a variegated pattern on it. This makes it more pleasing and interesting to look at." The extra labour is thereby compensated. This principle applies equally to paint on walls and the various stuffs required. On the other hand, applied carving or mouldings are excluded because they involve useless material. I admit that in order to include the systems of lighting adopted in the studios within this definition of functionalism it must be granted that indirect lighting is a necessity in order to avoid eye-strain, for, it is not otherwise defensible. In one tiny lobby there are six concealed electric lamps throwing their light on to a ceiling. One exposed lamp would do the same work. It is not easy to find excuses for such extravagance, but it is very pleasant.

The transition from this digression on functionalism to the work of Mr. Wells Coates is an easy one, for he has designed the most entirely functional of the studios, those used for the reading of news and the dramatic effects studio. The news studios and the lobby attached are diminutive rooms containing little more than a curved table running parallel to the wall and a swivel chair.

The dramatic effects studio is as exciting as a magician's cave, and indeed would be taken for such by a savage. For one machine makes thunder; another howls like a February gale. Two neat boxes produce electrical noises; a tank, the prattle of a stream or the roar of a waterfall. A rotating table in the middle has a surface divided into six compartments made of different substances for various percussion effects. The floor has a concrete area and a wooden area for different footsteps. One corner is dedicated to railway noises. All this apparatus is housed and disposed with extreme neatness and compactness. Two microphones suspended from the ceiling and operated by two long jointed arms can be placed beside any "effect" while it is in operation. Even a layman can enjoy all the ingenuity and efficiency of these contraptions, but it probably requires a specialist to appreciate to the full the apparently effortless success of Mr. Wells Coates's achievement.

Of the remaining studios which must be mentioned, three are the work of Mr. Serge Chermayeff and two large ones in the basement of Mr. R. McGrath. Mr.
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Chermayeff's largest studio is used for bands and orchestral concerts. It is the only studio in the B.B.C. building which is lit by daylight, and it is interesting to see how well it passes a test to which the others are not subject. The room is quite shapeless and six large circular "ventilating pans" placed in haphazard positions on the ceiling would have defeated any hope of success except in a "functional" treatment. As it is these blemishes of planning hardly seem to matter at all. Long strip lights are placed across the disks in the ceiling, which is painted with an apparently haphazard pattern. This is echoed in the cork matting on the floor. In neither case is the pattern at all obvious. Probably most people are unconscious of it, but it is just these touches which make the large empty rooms look so different from the gymnasium at a private school. The walls are drab wall-board with narrow white metal joints. The only notes of colour are bright green doors and striped coral pink settees.

Mr. Chermayeff's two talks studios are extraordinarily interesting examples of functionalism applied to intimate uses. The colours are all low in tone and harmonise. The lights are shaded, the furniture is comfortable with a comfort which one feels is produced by a profound study of anatomy. The rooms seem to induce bodily well-being and mental alertness. Here one feels is a setting in which lean-faced scientists can discuss relativity, or the more intellectual members of the Communist party an ideal distribution of wealth. One cannot, however, imagine oneself making love in them or playing with one's children in them or even littering them with books and magazines. But for the rather impersonal uses to which these rooms are put they seem perfectly adapted. Even the most unselfconscious cannot entirely relax when chatting to several million people.

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Mr. McGrath's two studios are for vaudeville productions and for dance bands respectively. The Vaudeville Studio is a small theatre which will accommodate a limited audience. The general scale of colour is quite appropriately much gayer than in the talks studios. In fact Mr. McGrath is a real magician with colours. I was trying to find names for some of the colours in the Vaudeville Studio and decided that one part of the wall might be called "mushroom" pink. On examining it closely I found out that it was, in fact, simply drab wall-board, but the surrounding tints and the lighting mysteriously trans-coloured it. There is nothing which could even remotely be called ornament in the room, yet bands of lead-colour, primrose yellow, pinks of different shades, and greys, combine to make up a room: which seems palpably and exactly adapted to its purpose. And the best of it is that in a few years if the room becomes shabby or hackneyed it can be repainted in different colours and become quite unrecognisable.

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The jazz band studio is even simpler in form than the theatre, for such incidents as a stage and its "wings" are missing, but its colours are particularly amusing. The walls are covered with drab wall-board with bright blue joints about one inch wide. There is a high lavender dado on which are mottled-red and black stripes. Nearly all these colours coincide with changes of material due to the given proportions of reverberating and non-reverberating surfaces. A clock with a copper face and a black-and- white floor complete a room which seems the appropriate cave of harmony for the droning saxophone, And so we must leave Mr. McGrath and his colleagues suiting design to purpose to the last.

From the 1933 Year Book
The Control Room Amplifiers
The Control Room contains a large number of low frequency amplifiers which serve to amplify the various transmissions originating in or passing through Broadcasting House. These can be divided into four principal types known respectively as A, B, C, and D amplifiers. The A Amplifier is purely a microphone amplifier and raises the level of the transmission from the very weak microphone output to a level suitable for controlling. The B Amplifier serves to make up the loss introduced by the control potentiometer and any fade unit in use; it can further raise the transmission to a specified level (known as zero level). The C Amplifier is a single stage amplifier only, and its purpose is to separate the outgoing land-lines from the output of the B Amplifier. The D Amplifier is used to raise the level of transmissions incoming by land-line, such as Simultaneous Broadcast and Outside Broadcast transmissions. The general functions of each type of amplifier will be more readily understood by reading the foregoing remarks in conjunction with the diagram shown as Fig. 1.

Figure 1:
Typical arrangement of control room amplifiers

The types of amplifiers will now be considered in more detail.

A Amplifier

This amplifier (see Fig.2, below) is a three-stage resistance-coupled amplifier having input and output transformers. Its input impedance is made 300 ohms to suit the output from carbon microphones which, until recently, were used more than any other type. Where a condenser microphone is used it has its associated single-stage amplifier located with it in the studio and the output impedance of this amplifier is made suitable to work into the 300 ohms input impedance of the A Amplifiers. The output level of the condenser microphone amplifier is also attenuated locally, where necessary, so that all microphones in use deliver transmission at approximately the same level to the A Amplifier input for a given sound intensity in the studio. Similarly where gramophones are used the gramophone attachment is followed by a network such that (a) the transmission level is approximately the same as that obtained from a carbon microphone, and (b) 300 ohms forms a satisfactory termination. Normally one particular A Amplifier is associated with each studio, but any one may be used for any studio if required, since the input is suitable for all types of microphones, gramophones, and associated mixers, in use.

Figure 2: Diagram of an A amplifier

A switch is provided on the front of each A Amplifier which when operated inserts two correction circuits, one in the second grid circuit, and one in the third grid circuit. These circuits are such that when in use they modify the frequency characteristic of the amplifier to compensate for the frequency characteristic of certain microphones.

The third stage is duplicated, the first output being used to pass the transmission to the input of the fade unit and potentiometer used for controlling, while the second output is used to pass the transmission, via a loudspeaker amplifier, to the Echo Room, where it is picked up on another microphone and passed, via a separate A Amplifier, to another input of the same fade unit to provide echo. When echo is not required the second output is not connected through to the Echo Room. Indirectly heated valves are used to reduce valve noise (that is to say, "ponging") and to minimise interference incoming from the filament supply leads, caused by switching other amplifiers fed from the same battery. To reduce further such interference a decoupling choke and condenser are included in the filament supply to each amplifier. The grid and anode circuits of the first and second stages are also decoupled to minimise interference incoming via grid bias and high-tension supply leads.

The A Amplifier has an overall voltage magnification of approximately 360 (51 decibels). The transmission level at the output of all A Amplifiers should be approximately the same, to facilitate fading from one studio to another, and to secure this the overall voltage magnification of the A Amplifier is reduced in cases where the output level from the microphone is high, as in studios where an orchestra or band is playing. This reduction of magnification is obtained by means of the potentiometer in the first grid circuit. In practice the full magnification is only required in the case of talks studios where the sound intensity at the microphone is relatively low.

The filament supply is 4 volts, the high-tension supply 300 volts and the grid negative bias 2, 12, and 24 volts for the first, second, and third stages
A Puzzle
It's mentioned in this article and elsewhere that there were 21 amplifiers for the studios - but there were 22 studios. Which one didn't have an amplifier? Possibly 7A: there are references stating that its output was available on the 6A mixer, so perhaps it wasn't available as a separate source in control room, and therefore didn't need an amplifier.
respectively. The high-tension and grid negative supplies are taken from central batteries which are used to supply all the other amplifiers in the Control Room, but the filament supply is taken from a central battery reserved for the A Amplifiers only.

There are 31 A Amplifiers in all; 21 used for studios, 5 for Echo Rooms, 3 for miscellaneous purposes, and 2 spare.

B Amplifier

This is a three-stage resistance-coupled amplifier similar in many respects to the A Amplifier. The main function of this amplifier is to make good the loss introduced by the controlling potentiometer and to amplify the transmission, from whatever source it is obtained, to a specified level, referred to as zero level. This level corresponds to 10 milliwatts of A.C. power for a sine wave, so that as the normal output load is 600 ohms, this gives 2.45 volts R.M.S. across the output terminals. This means that during a programme the level at the B Amplifier output will be such that on loud musical passages the mean A.C. voltage across the output terminals will be 2.45 volts. The use of the B Amplifier to overcome the loss in the controlling potentiometer can be seen by reference to the Transmission Level Diagram (Fig. 3).

Figure 3:
Typical level of transmission

The voltage magnification of the amplifier is approximately 200 (46 dbs.). In practice the full magnification is seldom required and it is reduced by means of the potentiometer in the first grid circuit to a value of about 80 (38 dbs.).

B amplifier
Back view of the B amplifier bay
Directly-heated valves are used in this amplifier as, the general level of transmission being higher, the relative amplitude of microphonic and other interference is less. The filament, grid, and anode circuits are decoupled as in the case of the A Amplifier. There are in all 16 B Amplifiers; 6 allocated for transmission programmes, 8 for rehearsal programmes and 2 spare. Each B Amplifier, except the spares, is associated with a particular Control Position. As a general rule it can be said that the number of B Amplifiers in use at any time corresponds to the number of programmes (transmission or rehearsal) passing through the Control Room at that time.

The B Amplifier is fed with 6 volts, 300 volts, and grid bias tappings of 2, 12, and 24, from the Control Room central batteries.

C amplifier bay
C amplifier bay with the cover removed from one amplifier
C Amplifier

The C Amplifier is a single-stage trap valve amplifier having no voltage amplification and serving to separate each individual outgoing line from the B Amplifier output. In many cases it is required that the level of the transmission outgoing on a trunk line shall be less than the specified zero level, and in such cases the level is reduced by means of the C Amplifier input potentiometer.

D Amplifier

This is similar to a B Amplifier except that an additional output stage is introduced for echo purposes. It is used to amplify the transmission incoming from any line and has a maximum voltage amplification of 200 (46 dbs.). As the level of such incoming transmissions may vary considerably for different lines the overall magnification of the amplifier can be varied by means of the potentiometer in the first grid circuit.


In addition to the above four main types of amplifiers there are various other amplifiers for special purposes. Among these are Trap Valve Amplifiers which have three separate output stages, one for supplying the "controlling" engineer's headphones, one for supplying headphones in studios and offices in the building, and one for supplying loudspeaker circuits in various parts of the building. Six of these amplifiers are allocated for transmission programmes, one being permanently connected to the output of each of the six transmission B Amplifiers. Thus any headphone or loudspeaker circuit may be supplied with any transmission programme at any time by connecting this circuit to the output of the particular Trap Valve Amplifier. In addition there are three spare Trap Valve Amplifiers which can be used for rehearsals or miscellaneous purposes.

The programme is fed into the loudspeaker circuits from the output of the Trap Valve Amplifier at ordinary headphone strength, and at each loudspeaker point a two-stage amplifier raises the level to full loudspeaker strength. This amplifier is operated from the A.C. mains and has a single valve in the first stage, and two valves in push-pull in its output stage.

From the 1934 Year Book
How Broadcasting House is Run
Enough has been written on Broadcasting House for it to be realised that the house itself is essentially functional, not only from a purely mechanical aspect, but from the point of view of the human element by which it is ensured that the mechanism carries out its allotted task.

It might be thought that, apart from the actual transmissions or performances in the studios, there is little about Broadcasting House to distinguish it from the thousands of other large offices in London or the Provinces. There are, however, very many differences, and while it is essentially the preparation and presentation of programmes which account for these, the organisation both of personnel and studios provides work which is in marked contrast to the normal business routine. For example, individual programmes and programmes as a whole are built on a co-ordinate design, or may be dependent upon some personality, and it can easily happen that some unexpected defection causes an unavoidable change of plan - an artist may fall sick or a musical work be not available; this will in many cases necessitate a complete revision of many days' arrangements in order to maintain the sequence and balance of the altered programme in relation to those preceding, following, or providing alternatives to it. It is also vitally essential that every cog in the intricate organisation should not only intermesh with its complementary cog, but that each and all of them should work almost to a time schedule of seconds. The organisation must therefore be sufficiently rigid to ensure punctuality in the transmissions, but at the same time be elastic enough to enable the temperamentally minded to give their best work without being irritated by too many regulations.

Let us consider the formation of a broadcast programme through its various stages from conception to performance, together with the ancillary services which those primarily concerned must needs either call upon, or with which liaison must be effected. The booking of artists is by no means necessarily the first step. An earlier stage is the casting of the programme, the requisitioning - either from the Corporation's own libraries or by hire - of the music or play as the case may be, and the settlement of any copyright questions which may be involved. Here naturally the Library, Booking, and Copyright Sections are brought in, while simultaneously the Programme Routine Section must be given the fullest possible details of the programme in order that Regions may be advised what material is available for them to take S.B., and so that their own programmes may be suitably formed to provide good alternatives to the National transmitters. (The Regions, on the other hand, notify Head Office what material of National interest they have available for the London programmes.) The programmes are at this stage many weeks ahead of actual performance, and it is the function of the Programme Routine Section also to feed the Radio Times with all its programme pages. This means not only the careful checking of all details such as titles, composers' names, speakers' degrees and qualifications, etc., but also the constant advising of all who may be affected of corrigenda and addenda to programmes. The advent of Empire Broadcasting has of course meant a duplication of these services for Empire programmes, and in this case the Empire Edition of World-Radio has similarly to be served with its programme pages at the appropriate period in relation to the date of publication of the various issues in time for the information to be available in the Zones themselves.

It will be appreciated that some differences between the programme actually performed and those published in the Radio Times or World-Radio are inevitable owing to the aforementioned unexpected changes, but it is vitally essential, not only for the publicity issued to the daily press to be up-to-date, but also for the actual programme which the Announcer uses at the microphone to contain every alteration or addition.

The system of simultaneous broadcasts moreover necessitates absolute accuracy at the time of performance, as the Engineering Branch, which is responsible for the provision of the interconnecting lines, must be provided with a chart showing in every detail whither and whence every programme is to go and the route which it has to take.

All these are purely routine functions, which are carried out in regard to all programmes of whatever type, and, broadly speaking, do not vary in their nature; they may, in fact, be looked upon as the framework of the actual programme organisation.

Now a little more detail as to the preparation and performance of the programmes themselves. The various departments having been informed which periods of the day's programme they are being asked to fill, the artists, actors or speakers having been booked and their material obtained, it is necessary to arrange for rehearsals. It is probably common knowledge that Broadcasting House has twenty-two studios, and it is equally probable that the question is asked, Why are so many needed for putting out two programmes? In the first place, it is a fallacy to think in terms of two simultaneously transmitted programmes only, since it is quite possible that in transmissions alone Broadcasting House might be doing its own National and Regional programmes at the same time as an Empire transmission, as well as contributing individual items to Regional programmes. There are, however, far more hours spent in rehearsals than in transmissions, and it is a matter of considerable adjustment and mutual give and take between those needing studio accommodation before all can be fitted in. Not only the question of the actual studios has to be considered at this juncture, but also the type of microphone which is necessary for the particular programme, whether or not echo is to be used for all or part of the transmission, and such details as what equipment is needed by the performers. Under this latter heading come such items as instruments for bands and orchestras, music stands, the conductor's rostrum or, in fact, any studio furniture of a temporary or removable nature. When, for instance, a military band is rehearsing in a studio on the eighth floor, all its instruments have to be taken from the band-instrument room in the basement, set out in the studio, and returned
Studio 10
There were nine studios at Savoy Hill, none of them big enough for larger musical programmes. "No.10" Studio entered service in 1930 and was built in a disused warehouse on the South Bank of the Thames, almost opposite Savoy Hill. At 67 x 70 feet it was at the time the largest broadcasting studio in the country and was used by groups as diverse as the BBC Symphony Orchestra and Henry Hall's band. It closed in 1934 when the Maida Vale studios entered service.
into safe custody afterwards; at the same time a section of the main orchestra may be playing in "No.10" studio by Waterloo Bridge - with similar transport implications. The average listener possibly does not realise the extreme delicacy of musical instruments and the fact that only experts can be employed in handling them. Even so, damage is apt to occur, and it is essential for the Corporation to cover such contingencies by insurance, lest its employees should be responsible. In this connection an interesting point arose at No.10 studio when it was first adapted. This building was originally a wine store, and as such was specially constructed to avoid possible deterioration of the wine through damp. This was in many ways very desirable, but it was only after a band-instrument room had been made, and used, there that it was discovered that the dryness of the atmosphere caused wooden instruments, double basses and such like, to crack. This was, of course, most serious, but the bother was eventually overcome by the construction of a series of trays containing water round the walls of the instrument-room, which provided the requisite humidity.

But to return to programmes, there are not only musical transmissions to be rehearsed; speakers, the Children's Hour, plays and variety, all and sundry, must be perfected before the final presentation. Plays, for example, need their effects, which in their turn call for the studio and staff allocated specially for producing "noises off", whilst the Dramatic Control Panel has to be manned either by the producer himself or a member of the Balance and
The Dramatic Control Panel
Control staff. These activities need also the collaboration of the Engineering Branch in the form of the connecting mechanism of the Control Room - the technical nerve-centre of broadcasting.

Alongside these preparations for actual programmes there are a certain number of auditions of new talent to be held, for although at the present time there is an excess of "straight" musical artists, the Dramatic and Variety Departments, the Children's Hour and the Talks Branch are always on the look-out for new material with which to vary their fare. Thus there are the three stages of audition, rehearsal, and transmission all proceeding (though of course in relation to different programmes) simultaneously and continuously. Nor is this all that attaches to the finished article - all programmes over a given period must come within a scheduled financial budget, and it is the business of the Programme Finance Section to watch this and to keep a fatherly eye both on expenditure and - in conjunction with the respective booking sections - on the terms of the contracts themselves.

There are many opportunities for the B.B.C. to come into contact with matters legal, not only defensively on the few occasions when, perhaps, a speaker may inadvertently give offence to some vested interest, but more often to guard the rights and privileges of the Corporation against broken contracts, infringements of copyright, and such-like happenings. For this purpose, as well as for other administrative necessities (leases, agreements, etc.), there exists a legal department which must be kept in close touch with all activities which involve contractual relations with outside bodies or persons.

Finally, the broadcast itself has to put a fitting crown on all the weeks of preparation which have gone before. From the Commissionaire on the door, the Receptionist in the hall, the Lift Attendant and finally up to the Announcer at the microphone, the artist must be conveyed easily and comfortably in order that the best result may be obtained.

As to programmes, then, the following chart gives them in skeleton form, in order to show briefly the sequence of programme construction and the departments closely affected.

This naturally only visualises programmes in the form of a generalisation, and ignores such entertainments as Outside Broadcasts, Foreign Relays, News, or the hundred and one varieties of music and speech which are capable of being broadcast.

Foreign relays may take the form of an ordinary Outside Broadcast, a relay of some foreign programme, or a special broadcast from the studio of some overseas broadcasting organisation which is not broadcast by that organisation (some of Mr. Vernon Bartlett's talks from foreign capitals are instances of the last type).

The last kind of relay quite naturally gives rise from time to time to reciprocal facilities being asked for in this country for representatives of foreign stations. This is relatively simple where time differences between this country and the places of broadcast are not great, but with America, for example, it may mean special arrangements being made as to staff, etc., in the small hours of the morning. This, however, does not call for so much extra organisation since the regular Empire service started as when midnight or thereabouts really was the B.B.C.'s "Goodnight."

The Restaurant
More mundane matters need the attention of the broadcasting staff, and such commonplace factors as food, and even sleep, have to be catered for within the walls of Broadcasting House, As has been said, rehearsals of many programmes are taking place daily, and every session must be broken at some given time for a "breather." In the basement at the broadcasting headquarters there is a restaurant which must be capable of providing meals or light refreshments throughout the twenty-four hours of each day, since a fifteen-minute interval does not afford time to the artists to go outside for a coffee. Contrary to rumours which have been current from time to time, the building is not licensed for the sale of alcoholic beverages, but this does not affect the patronage of the restaurant. Should the B.B.C. chorus and a large section of the orchestra be at rehearsal on the same day, as many as three hundred persons may want food within a short space of time, and it may be taken for granted that producers and conductors will brook no untoward delays.

The Empire transmissions run into most of the early morning hours - and the staff on night shift must be fed at the normal mealtime intervals as though it were day. Furthermore, it is not possible for one announcer to cover the late evening and early morning programmes (finishing with the Canadian Zone at 3 a.m.), and also to take the Australasian Zone transmission, which begins at certain times of the year at 5.30 a.m.

Neither is it economically practicable to expect these members of the staff to live either on top of the building or permanently in a near-by hotel. As a result, arrangements must be made whereby one announcer may go to bed at 3 a.m. and be able to get a reasonable period of sleep (which means that his quarters must be sufficiently quiet to enable him to sleep whilst the day-time staff arrive and work), whilst the man who starts announcing at 5.30 a.m. must have facilities for sleeping up to the time he has to prepare for his programme. Similarly the Control Room staff concerned must be present all night as well as those House Engineers who are responsible for services such as the ventilation plant, heating, lighting, lifts, etc.

Some little time ago the listening public was "scandalised" by a speaker being unable to give his talk owing to a missing manuscript. 'There was naturally no excuse for such a lapse, but it may be of interest to realise that the routine must be such that the manuscript is submitted in reasonable time for it to be read, altered if necessary, and returned to the speaker, and for copies to be made for the Listener and World-Radio (in case it is desired to publish), for the Announcer (in case the speaker forgets to bring his copy), for file purposes (in case the speaker takes away the copy he has used) and in many cases for re-reading later in the evening for an Empire Zone. This is all fairly plain sailing provided the original MS. comes in punctually - which it frequently does not - although last-minute alterations are apt to be troublesome, but there are added complications when a topical talk is broadcast without a manuscript having been submitted or when a debate is extempore. The B.B.C. must be in a position to know definitely what has been said over the microphone, and where there is no manuscript a night stenographer (with reporter's speed of shorthand) must be present, who will not only provide a permanent record of the talk, but may have to get it typed in time for an Empire Zone the same night, or for sending to the printers the next morning if it happens to be press day for the journal concerned in the publication of it.

Some talks, or maybe composite programmes, are recorded either on wax or on magnetised steel tape for subsequent reproduction to the Empire Zones. This is an obvious convenience, since it enables the Empire listeners to benefit by items which could not be repeated several times for their especial benefit. The Blattner-Stille system, which uses steel tape, provides facilities for immediate replaying, while wax recording necessarily involves some delay between the actual performance and its reproduction. The Recorded Programmes Section of the B.B.C. handles the programme aspect of this work in liaison with the Engineers, who are responsible for the technical side. It is the Recorded Programmes Section which also provides - in response to requisition from the programme builders - the gramophone recitals which are such a popular feature of current programmes. This work may not be quite so simple as it appear on
Gramophone Library
the surface, since not only must the gramophone programmes be constructed as artistic entities, but it is desirable in common equity to ensure that no one publisher, composer or record-making company obtains an unfair representation in them. There is also the routine work of obtaining from the manufacturers the records required, and, in the case of Regional recitals, their packing and despatch. The Corporation is building an extensive library of gramophone records, and the provision of records for all broadcast recitals is handled at Broadcasting House; the records being returned to the library after use. It is not usual to employ the same actual disc for transmission as has been used in rehearsal.

It is naturally most useful to the Corporation to know from listeners' letters how programmes are appreciated or disliked, and the Correspondence Sections provide tabulated details of criticism or appreciation, as the case may be, besides answering the innumerable inquiries on programme matters which are received daily. For this latter purpose, as well as for other needs, a detailed record of every item transmitted must be prepared - which in itself forms an invaluable history of the progress of broadcasting.

Bookshop and box office
Other activities of the B.B.C. comprise the holding of concerts, a part or all of which may be broadcast and to which the public are admitted, including, of course, the annual Promenade season at the Queen's Hall. These necessitate the normal box-office facilities, the ticket office at Broadcasting House being alongside the bookshop where B.B.C. and other publications may be obtained. The Radio Times, World-Radio, and other broadcasting journals must naturally carry their quota of advertisements to enable them to pay their way, and one of the busiest departments is that responsible for selling advertising space.

Television must be referred to in this survey of the activities within Broadcasting House, even if only because it calls for many requirements (other than technical) that ordinary broadcasting does not. To begin with, the studio itself is peculiar, in that the background for the artist is a white sheet, whilst the floor is designed in large black and white squares - like a chess board. Special lighting is also needed. Then, in view of the fact that television in its present state gives better results when the object is coloured black and white, artists' faces have to be made up with a dead white skin with the features marked out in black. Artificially blacked eyebrows are not perhaps unfashionable. Finally, the necessity for using two wavelengths - one for sound and one for vision - means that television must be given at times which do not interfere with the ordinary programmes; at present, then, these transmissions usually take place between 11 p.m. and midnight.

It is not possible to do more than mention many of these services which are so much part and parcel of the satisfactory conduct of a broadcasting organisation, but it may not be obvious to all listeners that such supplementary activities do exist, or that the home of British broadcasting does house so much that is not actual programme compilation or transmission.

One of these extraneous organisations has been created by the advent of Broadcasting House itself - namely, the handling of the thousands of applications from all and sundry for permission to see over the building. The B.B.C. is anxious to meet such requests from listeners as far as it is able, but it has been found quite impracticable to keep open house for all. In the first place, it is not possible for parties exceeding fifteen at a time to go round the building, since, for one reason, the guide's explanations would not be audible to a greater number; moreover, the congestion in passages, lifts and studios would become impossible. Furthermore it has been found from experience that considerable disturbance is caused to rehearsals by a procession of sightseers passing through studios, whilst, naturally, actual transmissions must exclude visitors from considerable parts of the building at all hours of the day. In consequence, only one tour a day (excluding Saturdays and Sundays, which are "closed" days) is all that can be handled, preference being given to those who have some definite contact with broadcasting, such as technical societies, persons in business relations with the B.B.C., visitors from Empire or foreign broadcasting staff and so forth. It is regretted, then, that disappointment is caused to many hundreds of applicants each week, but is quite unavoidable.

The administrative machinery required to co-ordinate all the different and differing sides of the B.B.C.'s work must of necessity be comprehensive and exact in its action, since as has already been pointed out, the aim of all departments must be to focus results on a nearly inflexible time schedule, while working under conditions of fluctuating circumstances where the human element is inevitably preponderant. Many details have been covered in this or earlier issues of the Year-Book, and the object here has been to try to enable those interested to picture some of the pieces which go to form the composite structure of broadcast entertainment.

From the 1933 Year Book
Ultra-Short Wave Broadcasting

The Marconi type SWB4 transmitter installed on the seventh floor of Broadcasting House.
In previous issues of this book, information has been given about the serious congestion of the broadcast wave-bands due to there being insufficient ether channels to provide accommodation for all the broadcasting stations of Europe. Extensions to the broadcasting service in this and other countries are restricted on account of this difficulty. It is natural therefore that every effort should be made by technicians to discover the usefulness or otherwise for broadcasting purposes of wavelengths which so far are not in common use.

In broadcasting it is necessary to provide a reliable service to as wide an area as possible, while at the same time using an economical amount of power at the transmitting end. For a reliable service the listener must receive the direct or ground ray, and must not have to depend upon the indirect or reflected ray, which is subject to fading and distortion of quality. The range of the direct ray on medium broadcasting wavelengths between 200 and 545 metres is about 50 to 80 miles, whatever the power. Beyond this distance, some fading is bound to occur. On shorter wavelengths the area which can be provided with a direct-ray service is less, but the strength of the indirect ray which can be heard at long distances from the transmitter, after the direct ray has completely died out, may be appreciable. This property of short waves is used for communication over long distances. For example, on 25 metres the direct ray may be inaudible beyond a range of about 20 miles, but it may be possible to receive the indirect ray after reflection from the Kennelly-Heaviside layer when it strikes the earth at a distance of perhaps 5,000 miles from the transmitter. The efficiency of a particular wavelength for long-distance communication depends upon several factors, such as the time of day and the time of year, and in no circumstances is a service of this character entirely free from fading and distortion.

Now a great deal of interference between broadcasting stations working on adjacent wavelength channels, or on the same wavelength, is caused by the indirect ray of a distant station being audible in the direct-ray service area of another.

Progress in the last ten years in wireless communication in general, and broadcasting in particular, has been so rapid that even the short waves (under 100 metres) are becoming congested. Ten years ago little was known about the performance of waves in this band, but intensive research has resulted in the rapid growth of long-distance communication services using these waves.

As already explained, short waves are of little value for providing a national broadcasting service because of the rapid attenuation of the direct ray and the objectionable features of the indirect ray. To meet the need for further expansion, attention is therefore being directed to ultra-short waves under 10 metres. The band of frequencies is an extremely wide one - for example, between 6 and 8.5 metres there are approximately 14,700 kilocycles, a band almost fifteen times as wide as the whole of the existing medium wave broadcasting band of 200 to 545 metres.

If therefore these waves can be used for broadcasting, the problem of congestion will almost cease to exist. Sufficient work has, however, already been done to show quite definitely that ultra-short waves can never replace the medium and long waves already used for broadcasting. The reason for this is that the range of the direct ray is even more limited than that discussed in connection with short waves. However, there are compensating advantages which make the subject worthy of further investigation.

In order to study this subject, the B.B.C., in co-operation with Marconi's Wireless Telegraph Co. Ltd., have installed at Broadcasting House an ultra-short wave transmitter, but before describing this in detail, some further advantages and disadvantages of this band of wavelengths, as far as are at present known, should be mentioned.

From earlier work carried out in America and Germany it is known that for all practical purposes the range is very limited. From what has already been said about short waves it might be thought that any hope of ultra-short waves being usefully employed for broadcasting would be doomed to disappointment. However, this is not so, since certain advantages appear which offset the disability of rapid attenuation of the direct ray.

The results of earlier experiments seem to show that these waves are not reflected at all by the Kennelly-Heaviside layer. Thus the indirect ray and all the troubles of interference which it brings with it virtually do not exist. It would be possible therefore to have a large number of ultra-short wave transmitters on adjacent wavelengths or even on the same wavelength, each providing a local service up to a range of say five miles in densely populated areas. Further, the scanty evidence so far obtained indicates an almost entire absence of atmospheric disturbances on these waves.

For a reliable service, the strength of the required transmission must be high compared with the strength of the interference from whatever source. Since the latter is apparently low, it follows that a relatively weak signal, as compared with that required on medium waves, will be sufficient for listeners' requirements. However, it is too early to say what order of field strength will be desirable, and consequently it is not known what transmitting power will be necessary to provide a reliable service over a range of say five miles from the transmitter.

To provide a true picture of what may be expected from this new field, a few of the disadvantages which are already known should be mentioned. Needless to say, further experiments may bring to light unexpected difficulties which may destroy what value these waves may have in other directions.

The strictly limited range has already been mentioned. The difficulty of reception must also be considered. Short-wave receivers are not so easy to handle by the non-technical listener as are ordinary broadcast receivers. However, as the need arises so will technical design improve, and it is not unlikely that the most common receiving set for ultra-short waves will consist of an ordinary medium-wave set in which provision has been made for adding a small short-wave unit to convert the set into a super-heterodyne or super-regenerative type of receiver.

It is believed that the ignition systems of motor cars cause considerable interference to receivers tuned to these wavelengths. Whether this can be overcome by a suitable increase in power of the transmitter has yet to be discovered. As no absolute measurements of field strengths on these waves have been made, it is too early to say whether the interference is due to its own high level or to the low level of signal from the transmitter.

Another likely trouble is shielding. It may be found that in a City with steel-frame buildings, reception is extremely unreliable. In one street it may be good and in the next no reception may be possible. This may lead to receivers being placed on the roofs of buildings, or, alternatively, the aerial (which, of course, is very short on these waves) may be on the roof and connected by means of a high-frequency transmission line to one or more receivers on the floors below.

A Marconi type SWB4 transmitter has been installed in a room on the seventh floor of Broadcasting House, and the output is connected by means of a high-frequency feeder line of the concentric tubular type to a coupling box on the roof immediately underneath the aerial. This is supported by means of a triatic slung between two lattice steel masts each 35 feet high, and is of the Franklin type, consisting of two half-wave aerials with a phase-correcting device in the middle.

The transmitter consists of four units, the main rectifier unit, the auxiliary rectifier unit, the modulator unit, and the oscillator unit. Power is supplied
Rectifier Units
The Rectifier Units
from the mains at 415 volts, 3 phase, 50 cycles. After a voltage step-up by means of a transformer, the supply is rectified in the first unit by three air-cooled valve rectifiers. After smoothing, the D.C. power output is approximately 1,200 milliamps at 4,000 volts.

The second unit contains the auxiliary rectifiers for providing the various D.C. voltages for the earlier stages of the transmitter. A motor-generator set is provided for heating the high-frequency amplifier and modulator valve filaments, but the drive valve is heated by a 6 volt accumulator.

The third unit contains three stages, a sub-sub-modulator, a sub-modulator, and the main modulator comprising four valves in parallel. A high-power choke
Master Oscillator and Amplifier Unit
The Master Oscillator and Amplifier Unit
control system of modulation is employed, and the frequency characteristic of the modulator system is sensibly flat between 30 and 9,500 cycles. Amplitude distortion does not exist up to 80% modulation and is negligible up to 90%.

Finally, there is the fourth unit (right), which contains nine stages of high frequency. The frequency of the carrier wave is determined by a Franklin master oscillator working on 2,150.54 kilocycles (139·5 metres). This is followed by a five-stage amplifier. The first and third stages triple the frequency by selecting the third harmonic, the second, fourth, and fifth being amplifying stages. The output frequency is therefore nine times the initial frequency, which is thus increased from 2,150.54 kilocycles to 19,354·86 kilocycles (15·5 metres).

The output of this amplifier is applied to the first high-power amplifier. The output of this stage is connected to a doubling stage, which gives the final carrier frequency of 38,709.72 kilocycles (7·75 metres). The last link in the chain is the final high-frequency amplifier consisting of two valves in parallel and modulation takes place at this level.

Of course, these figures apply to one adjustment only. The experimental transmissions have been started on this wavelength, but investigations will be made over a band of about 6 to 8·5 metres. It is quite possible that while a wavelength at one end of the band may give poor results, another a metre away may be very satisfactory.

Studio BB in Broadcasting House was used for television experiments from August 1932 until February 1934. John Logie Baird wrote this article for the 1933 Year Book.
Television in 1932
by J. L. Baird, Managing Director of Baird Television, Ltd.

A Seal being televised
A seal being televised in Studio BB
No one will gainsay that the year 1932 has proved to be a most important landmark in the development of this newest of sciences - television.

After nearly three years of experimental transmissions emanating from the Baird Studios in Long Acre and broadcast by the London Regional transmitter of the B.B.C., a sufficient degree of advancement has been made to justify the B.B.C. taking over the studio side of the work. In my opinion this constitutes the most important step which has yet been taken towards the realising of proper commercialisation and the introduction of television to the public at large.

It may come as a surprise to many to learn that as far back as 1926 television transmissions were broadcast by the B.B.C. These, however, were of an entirely experimental nature and were received only on our own machines; for apparatus at that date was not in the hands of the public. From these crude beginnings we were able to establish that television could be broadcast successfully by the B.B.C. transmitters, and from that date a steady progress commenced.

Negotiations with the B.B.C., which took place over a rather lengthy period, culminated in September 1929, when the first official broadcast of television was made through the new London Regional Station at Brookmans Park. A spirit of friendly collaboration was established and considerable technical knowledge of this important side of television has been acquired.

Steady progress then commenced, one of the results of which was the broadcasting of the play "The Man with the Flower in his Mouth," which was due to the united efforts of Mr. Sydney A. Moseley, Mr. Val Gielgud, and Mr. Lance Sieveking.

Another landmark in television progress was reached in June 1931, when a view of the winning post at the Derby was broadcast. This was repeated in 1932.

Miss Amy Johnson and Mr. J. A. Mollison
Miss Amy Johnson and Mr. J. A. Mollison being televised on the latter's return to England after his Atlantic flight.
The most valuable result of the years of experimental broadcasting which have been gone through has been the acquiring of a vast amount of technical experience. I feel, now that the B.B.C. has taken over the programmes and transmissions, advancement will be most rapid and the public can look forward to television programmes of sustained entertainment value.

In spite of the large amount of information which has been disseminated on the subject of television, I find that the majority of the general public are still in complete ignorance of what television means and how the process is effected.

In the space at my disposal, therefore, I propose briefly to outline both the transmitting and receiving sides of the problem.

First of all we mean by television the process of being able to see, through the medium of electrical methods of transmission, the reproduction of images of living, moving, or stationary objects which are at some distance from the observer. It can r really be looked upon as the reproduction of sight, for it is possible to witness visually what is happening at some distance just as if we were eye-witnesses on the spot.

Coming to the process itself the subjects to be televised are positioned in front of a Baird spot-light transmitter and explored by a rapidly moving spot of light. For the purpose of explanation let us assume we are televising the head and shoulders of an artist. In front of him is a powerful source of light which is broken up mechanically into a rapidly moving spot. This is effected by having a beam of light projected on a revolving drum around whose outer edge are positioned mirrors, each one set at a slightly different angle to its predecessor. The effect is to cause a tiny area of light to move from the bottom to the top of the subject's features and thus create a strip of light. Immediately this one spot has finished its movement, a second spot takes its place and performs an identical movement, except that this second strip is displaced to the left of the original strip. In this way 30 strips of light are built up side by side, each strip just touching its neighbour on either side, and although at any one instant only a tiny spot is visible, the process is carried out so rapidly, namely, 12½ times per second, that an onlooker would have the impression that the artist was completely illuminated.

A bank of photo-electric cells is placed in front of the artist, and this "television eye" follows the movement of the spot of light and picks up that amount of light which is reflected from the spot playing on the subject being televised. A corresponding current variation is then produced in the cell circuit, and at the next instant, when the spot has moved to its adjoining position in the light strip, a different amount of light is reflected and the cells respond accordingly.

In this simple way the scene is analysed, and the television signals are made to modulate the carrier-wave sent out by the broadcasting station and are transmitted through space as ordinary wireless signals. These can be detected and received in the normal manner by anyone possessing a wireless receiver. If however, the individual tuned in vision radio signals and passed them on to a loudspeaker, he would be rewarded with a peculiar note which makes no pretence at being musical. On the other hand, if the signals from the output circuit of the wireless receiver are passed to a "Televisor receiver" then the result will be an intelligible image which, in effect, is a replica in miniature of the artist in the television broadcasting studio.

The vision-receiving apparatus, in order to bring this about, must consist of a source of illumination, the intensity of whose light can be made to fluctuate in exact conformation to the variations which originally take place in the photo-electric circuit at the transmitting end. In the original disc model machine this source of illumination was a flat plate neon lamp whose large electrode glowed brightly or darkly according to the signal strength which was made to modulate it.

Baird Televisor
The new Baird "Televisor" (receiver), which gives a black-and-white image on a screen
In the new model machine, however, this neon lamp has been replaced by a projection lamp whose beam of light is now modulated by being passed through Nicol prisms and a glass cell filled with nitro-benzene, in which plates, similarly arranged to accumulator plates, are immersed. These plates are connected to the output of the wireless receiver, and as the voltage varies, the light passed by the cell varies in unison. This grid cell is a modification of the cell used many years ago by the physicist Kerr in his experiments with polarised light, but the use of grids in place of simple plates enables a low voltage to be employed and renders the device practical. The beam of light modulated by the grid cell is projected on to a revolving mirror drum, and this in turn is reflected on to a translucent screen positioned in front of the drum. Since the whole process is effected at a speed of 12½ times per second, the characteristic lag or persistence of vision of the eye interprets this as a continuous movement, in much the same way as the still pictures projected on to a screen at an ordinary cinema are built up into the continuous and apparently unbroken movement owing to this same property of the eye.

Television Abroad

In Germany, Fernseh A.G., a combination of the Baird Company, the Zeiss Ikon Optical Company, the Bosch Magneto Company and the Loewe Radio Company, which was formed in 1929 to develop our system of television, has supplied a transmitter to the German Post office which is very similar to that used by the B.B.C., and television in Germany is developing along parallel lines to developments in this country and we work in the closest collaboration.

A similar state of affairs exists in France, where Television Baird-Nathan is using the wireless station P.T.T. on the outskirts of Paris for the experimental broadcast of television, and we are now constructing a transmitter for them on the same lines as that being used in Broadcasting House.

In the United States of America extensive work is being done with television by the members of the huge combine known as the Radio Trust, and in addition numerous broadcasting stations are sending out television transmissions similar to those in Europe. The Baird Company of England has an affiliated Company in America, and last year W.M.C.A., one of the large broadcasting organisations of New York, arranged to take up the British system for broadcasting television, in preference to any American system offered them. An agreement was fixed with them, but the British Company was refused permission to broadcast in America by the Federal Radio Commission on the grounds that - to quote one of the leading technical journals:-

"…although the application was made in the name of W.M.C.A., an American Company, the proposed station would be operated jointly with Baird Television Corporation, Ltd., a British concern. According to the Commission, the granting of a licence would, in effect, give undue authority to the British Company in violation of the section of the Radio Law prohibiting alien ownership or directorates of Companies holding wavelength privileges in the United States."

It might be advantageous to our "Buy British" policy if this country were to adopt a similar attitude towards American-controlled concerns.

Television for the Cinema

The application of television to the cinema and places of public entertainment involves the use of a large screen, and considerable development work has been done in this direction.

The broadcasting of the play "'The Man with the Flower in his Mouth" was not only shown on the ordinary "Televisor" receivers but was also shown to a large audience on the roof of the Baird Long Acre premises on a screen 2 feet by 5 feet, and the same screen was shown in Paris, Berlin, and Stockholm; but while it attracted large audiences, the pictures could not in any way compare with the cinematograph, and the attraction was one of novelty.

Since that time the screen has been so far developed that it is now approaching the perfection necessary to give full entertainment value apart from the curiosity attraction, and I believe that one of the largest fields for television lies in the cinema of the future.