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| • | BBC monitors introduction | |||
| • | BBC 1922-1960 | |||
| • | BBC in the 1960s | |||
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| BBC Monitors 1922-1960 An personal history by Alan Shaw. Please read the introduction first.  The British Broadcasting Company Ltd. was formed in 1922 by three hundred manufacturers and shareholders as a commercial venture. As Chief Engineer, Capt. P.P. Eckersley had been involved with broadcasting from the very earliest moments; in February 1924, H.L. Kirke was appointed as Senior Development Engineer. By 1927, the influence of broadcasting on British society was so marked that by Royal Charter, this private company was rolled into the British Broadcasting Corporation [1] for a renewable term of ten years from 1st January 1927 under a Director General as chief executive with a formal executive, control, administrative and engineering structure. Funding was (and is) substantially provided by the British Government via a levy, the TV (then radio) licencee fee and the Director general reports to the govenmnent ministers responisble for broadcasting. The entire staff of the old Company was transferred to the new BBC. After the formation of the British Broadcasting Corporation, Development Section was renamed Research Department and H.L. Kirke C.B.E., M.I.E.E was appointed as Senior Research Engineer, later known as Head of Research Department. H.L. Kirke held this influential and pivotal post from 1930 for an astonishing twenty years. He was immersed in the format battles for the newly conceived television service [2] and was in-post during the design and construction of Broadcasting House, London, opened in 1932. In the BBC Yearbook of 1933 [3] Kirke wrote a detailed appraisal of current microphone technology for the public that would grace the pages of a modern journal. Under his guidance the BBC's iconic AXB microphone [4] was developed, made at one-tenth the cost of a bought-in commercial unit in a culture of 'best performance, lowest possible cost, make in-house if necessary.' He took his profession seriously inside and outside the BBC; records show that in 1943 (and presumably long before) he was active in The Institute of Electrical Engineers [5], and by October 1948 he was Chairman, probably the first Chairman since Jan. 1948 of the Acoustics Group of the Physical Society of Great Britain [6]. Proceedings show that on 25 Nov. 1948 he was in the chair. "The following paper was read and discussed - Apparatus for Acoustical Measurements at Low Frequencies" presented by Dadson and Butcher The earliest recognisable subjective evaluation of the loudspeaker was not by the BBC but by commercial company GEC's F.H. Brittain in 1932 [7], followed in 1936/7 [8] and in 1938 with a remarkable report which covered "Frequency response (Its effect on sound quality), Balance (Permissible variations and limits), The Listening Room (Its effect on reproduction), Harmonics (Their effect on sound quality), The Validity of Steady State Measurements and Summary of proposed method of Assessment of all available acoustical measurements." [8]. It is curious as to why GEC with its manufacturing knowledge of loudspeakers, its measurement and listening facilities and its own anechoic chamber [9] were not more closely involved with the BBC or indeed any other speaker parts suppliers. There is no mention of GEC drive units being examined in either BBC report [10, 11, 12]. Had they done so, and had the results been acceptable to the BBC, or had GEC been able to adapt them then the BBC may never have become involved in loudspeaker research although the GEC Presence Unit became, in time, a standard within BBC monitors. A horn tweeter drive unit minus the horn. .jpg) It is very fortunate for the speaker industry that Kirke had such a great personal interest in acoustics "Mr. H. L. Kirke observed that are the subject of acoustics had received too little attention, except by a very few, and it was still understood only by the few." [13]. This comment was seemingly made by Kirke in 1945, some fifteen years after the design of Broadcasting House, several years after Brittain's published review of loudspeakers and about three years before his chairmanship [6]. It is impossible to know what branch of acoustics Kirke was commenting on: it could have been studio acoustics, microphones or loudspeakers; he had an interest in all fields. In the area of loudspeakers, GEC's Hugh Brittain demonstrably had a thorough grasp of the subject, but as an employee of a commercial company, he would have been under no obligation to share that knowledge. But it is curios that GEC's knowledge and facilities was not drawn on. It is possible that there was a conflict of interest over GEC and the politics of the selection of the new TV system but "Although from the late 1920s the (GEC) laboratories maintained a watching brief on technical and patent developments in television, there is no evidence that the Laboratories contributed to the fundamental concepts of what became the Marconi-EMI 405-line system which was adopted as the UK standard, nor the Baird 240-line system which, after experimental transmissions over a period, was rejected." [14] Kirke must have had reason to believe that unlike the broadcast television system concept which was presented to the BBC by industry, in acoustics matters the BBC could not or should not draw on a pool of external knowledge. Or perhaps he had little confidence in that external pool. A secondary theme to Kirke's audio legacy was studio and building acoustics. A generation of engineers later during the 1970 and 80s, that work would become the main activity of BBC Research Dept.  From its conception and patenting in the mid 1920s the USA designed Rice-Kellogg (I.S.R.K.) unit USA was available to the BBC. This was mounted in a suitably large polished piano black floor standing cabinet coded LB/3 and the complete system named LSU/7 monitor speaker. The back was open. As for the listener at home in the 1920s and 30s they would have listened through headphones or simple valve receivers. The standard of monitoring in the studio over the LSU/7 would have been far superior to even the best listeners equipment. As the quality standard of domestic receivers increased, the performance gap between the sound at home and in the control room started to close. In January 1944, towards the end of the war, Kirke sailed to New York on the Queen Mary [15] [15A] [15B] to see for himself first hand the new VHF/FM radio service in action and progress in television transmission. Its likely that he was made aware of the development work underway at CBS Labs. by Peter Goldmark [16] on the modern LP record and rightly anticipated that the British audience would shortly follow American technology and entertainment trends. All of this amounted to higher fidelity. The limitations of transmitting (on AM) with its restricted low-fi audio bandwidth had been commented upon in 1934 "The interpretational qualities of speech and music reside in the upper frequencies and it is not possible to obtain naturalness unless the frequency range extends to 12kHz ... One of the reasons why the reproduced version of the human voice sounds unnatural ... is due to the absence of frequencies above 5kHz..." [17]. Upon his return from the USA later in 1944 it must have been evident to Kirke that the audio frequency response window was opening. Clearly, Kirke had a demonstrable interest in loudspeakers and microphones at this time [18]. The LP record and the wide-band VHF/FM radio system was in imminent prospect. As McLachlan wrote in 1934 "In broadcast programmes, induction, valve, and other noises which are imperceptible in a system inadequate to reproduce above 4.5kHz would assume undue proportions if the range were extended to 12kHz. Consequently,to realise the full benefits obtainable by extending the upper register, the noise-level of the input in the studio and in the transmitting and receiving apparatus ... must be very low indeed." [17]. Sometime between 1945 and 1947 Kirke authorised BBC research engineers to start work on a replacement for the LSU/7 monitor. In 1946 D.E.L. Shorter published "Loudspeaker Transient Response..." [19] which, when computerised measuring systems became available thirty years later could be traced as the origin of the waterfall measurement plot. The BBC Research Department's involvement under Kirke's supervision started by canvassing the speaker industry for a suitable wide-band driver. The next step was to verify its sonic and technical potential and wide bandwidth. The final step would be to approve its fitting to the new monitor cabinet. The final assembly would eventually be known as the LSU/10. The speaker investigation project was to became a greater challenge than even the new television system, and it ran for over thirty years. The performance of loudspeaker units evaluated by his research engineers was dismal. Seemingly the nascent loudspeaker industry had only a rudimentary technical understanding of their products and was practically clueless about how to maintain and improve quality. The industry put a bold spin on what was evidently extremely poor product. In 1948 Biggs told the public "Speech is an essential test (for a loudspeaker) and most people judge its reproduction accurately. The first test imposed on a loudspeaker by the Research Dept. of the B.B.C. is to listen to the reproduction of speech in the middle of a field, away from reflecting surfaces, and compare it with the original voice. A good loudspeaker should give good reproduction of speech, but it does not of necessity follow that it will be equally good on music, which requires a much wider frequency range" [20]. This was true. But in actuality what the BBC was experiencing as the fruits of the speaker industry was of desperately poor quality. "The performance of sixteen "high-fidelity" loudspeakers submitted by British manufacturers has been investigated. The results have been generally disappointing. The cause for this state of affairs is though to lie, not so much in any lack of ingenuity in design on the part of the manufacturers concerned as in the scant attention paid by them to simple subjective testing. It is true that the opportunities of comparison between direct and reproduced orchestral music are denied to most designers. On the other hand, the majority of the defects noted in our tests were clearly shown in the reproduction of speech, and in fact the results of the music tests, apart from yielding some information in the extreme low frequency range, and on certain non-linear distortion effects, did no more than confirm the conclusions arrived at in the speech tests. The technical equipment required to carry out a speech test under carefully controlled conditions is no more than any reputable loudspeaker manufacturer might reasonably expect to posses, and it would appear that either the designers have made too little use of this simple technique or that, in using it, they have neglected to make frequent and critical comparisons with the original sound."[10]. In addition, Kirke drew a damning conclusion about the speaker industries negligible progress towards greater fidelity in over twenty years 'The I.S.R.K. unit in itself (dating from the mid 1920s, used in the LSU/7) is remarkable for its relative freedom from low-damped resonances ... although a very old design, gives a general performance more pleasing than that of most of the modern loudspeakers tested [10]. As Kirke reported said in 1945 ... 'the subject of acoustics ... was still understood only by the few.' [13]. But the new (LSU/10) monitor speaker was a real necessity and high priority with high quality wide band broadcasting just around the corner - time was running against them. There was a growing sophistication amongst consumers, an embryonic hi-fi industry, magazines and the consumer was curious about the subject of reproduced sound. A contemporary example for 1948 said " ... bear in mind that the reproduction (at home) depends upon the quality of the input ... a better speaker will expose the distortion of sound worse than an inferior one. The B.B.C. are by no means blameless in this respect. B.B.C. quality when it is good, is very, very good but some transmissions are very bad ...". [20] .jpg) In 1947, H. D. (Dudley) Harwood joined the BBC Research Department from the National Physical Laboratory where he had worked on hearing aid design and loudspeaker calibration [21]. The same year, D.E.L. Shorter, with Harwood about ten years his junior had been mandated by Kirke to get to grips with the BBC speaker requirements. Either Harwood was specifically recruited by the BBC to bring his technical expertise in loudspeakers to the department or it was extremely fortuitous timing of the right man at exactly the right moment. No time was wasted [10]. BBC Research Dept. 1948 (second) report [11] written by D.E.L. Shorter, investigated by Harwood and signed-off by Kirke opens 'In view of the urgency of the situation, it was decided that the investigation (into the two-unit loudspeakers being made by Research Dept.) be temporarily shelved in order to concentrate on the immediate task of selecting a commercial product'. This implies that fearing the absence of a suitable commercial wide-range drive unit, Kirke must have previously authorised the engineers to investigate combining a low frequency unit with a high frequency unit each within their optimum operating range. We now take for granted. In their final report, jointly investigated by Shorter and Harwood, written by Harwood and signed off by the new Head of Research, W. Proctor Wilson (following Kirke's retirement) they open with the chilling comment that 'It may be stated at the outset that none of the (commercial) loudspeakers (drive units) examined was found to meet our requirements ...' [12] and report subjective opinions across the range of speakers such as '... the middle and high frequencies giving the impression of being detached from one another; definition was poor; the bass response extend lower than usual but was boomy in character; the high frequency response was deficient and the whole reproduction was heavily coloured ...'. After examining over forty wide-range loudspeakers they concluded that 'the results have yielded much valuable information on the correlation between subjective and objective assessments of performance, a subject which will be more fully discussed in a later report'. They had at least been able to select a concentric multicellular 15" Parmeko drive unit - a copy of an American Altec Lancing design which had performed adequately for the LSU/10 monitor speaker but they noted with concern that "... five further LSU/10 loudspeaker units, nominally identical (showed) considerable differences between the units ... of twenty more manufacturers samples all but one or two were found to posses objectionable (sonic) characteristic ... after a change in the manufacturing technique, six further samples were submitted but the general performance of five out of the six still exhibited (sonic) defects..."[11]. That was far from the end of the matter. Problems soon arose. 'Difficulties arose in repeating, in production models of the Parmeko loudspeaker, the performance achieved with the sample (in the 1-2kHz band) on which the selection tests had been carried out, and the present report indicates the extent of the compromise which must be accepted if these loudspeakers are to be adopted in their present form' and '... it was not possible to reproduce the characteristics of the prototype (1-2kHz) band, and it is thought that these characteristics were the result of a fortuitous combination of circumstances.' [11]. The LSU10 [22, 23] was eventually introduced around 1950 and was still to be found in the BBC in the mid 1970s - I remember one in the control room of BBC radio London, Hannover Square with the Lorenz LPH65 tweeter strapped to the front grille to extend the high frequency response. .jpg) The introduction of the LSU/10 in 1948 with its enormous 280ltr. thick-wall cabinet had a workable frequency range from 40Hz to only about 6kHz. It practice, it proved difficult to control the frequency response at the top end of the LSU/10's HF horn to better than plus or minus 3dB.[10?]. The 6kHz upper limit was adequate for monitoring in the BBC in the AM era (medium wave) from recorded music played-out from 78 rpm shallac gramophone records with their own restricted frequency response. But the LSU/10 was only a stop-gap. COOK [24] ALSON [25] Although the 1950s did not see the introduction of any new BBC monitors, this was a time when the BBCs detailed knowledge of the technical characteristics and limitations of loudspeakers and microphones was growing. Shorter's masterpiece I.E.E. paper, received No. 1957, published Apr. 1958 [26] opens with "Moreover, even a broadcasting or recording organisation must limit the size and cost of its listening equipment ...In practice, a monitoring loudspeaker is intended to represent the best product of its kind which could be used by a member of the listening public ...". But all of the BBCs research focus to this point had been concentrated in improving and controlling the quality of the middle and higher frequencies. It was not until a year later that James F. Novak [27] applied scientific synthesis to the low frequency performance of speaker systems with engineering models to explain and predict how bass drivers and cabinets behaved together at low frequencies. Continued in BBC in the 1960s References: [1] BBC Broadcasting House, London. Historical perspective. [2] BURNS R.W. 'John Logie Baird: Television Pioneer'. Baird naturally wished to experiment in broadcasting television signals from one of the BBC's transmitters (and) he therefore communicated with each H. L. Kirke a engineer of the BBC who later was later to become its Senior Research engineer. 'Kirke was very interested in helpful', wrote Baird. Several transmissions were arranged the television picture being sent by telephone line from Baird's laboratory to a BBC studio. Kirke then put it on the air through the BBC's radio transmitter and Baird received it again by wireless at his laboratory. 'Complete success was achieved by this method.'. Only three experimental transmissions were given, the three experimental transmissions were unsatisfactory and they came to an abrupt end. 'Someone "up above" at the BBC, Kirke would not say who, had ordered the transmissions to cease.' ISBN 0852967977 [3] BBC Yearbook, 1933 [4] BBC AXBT microphone. This led to the 1953 design BBC PGS/1 ribbon microphone (Coles/STC 4038) is still in production in 2008. [5] I.E.E. 'Discussion before the Wireless Section, 5th May, 1943'. "Mr H.L. Kirke said the title of the paper is perhaps unfortunate as it does not appear to give a proper indication of the subject matter and it is not very descriptive of apparatus..." [6] Physical Society (Great Britain), Physical Society of London, Proceedings 14 Oct 1948, 25 Nov 1948, Imperial College, London. [7] BRITTAIN, F.H., 1932. "A device for rapidly plotting loud-speaker response curves". J. Sci. Instrum. [8] GENERAL ELECTRIC COMPANY (of UK) Ltd., Research Labs.. "The interpretation of acoustical measurements. Part 1. Loud speakers" Report No. 6666 [9] BRITTAIN F.H., 1937. "The appraisement of loudspeakers" G.E.C. Journal mentioned in book 'The GEC Research Laboratories, 1019-1984' by Robert Clayton ISBN 0863411460 9780863411465. Google extract here [10] KIRKE, H.L., 2/1948. "The selection of a wide-range loudspeaker for monitoring purposes (First report)". BBC Research Department No. M.008 [11] "The selection of a wide-range loudspeaker for monitoring purposes (Second report)", BBC Research Department No. M.008/2, 1949/3 [12] "The selection of a wide-range loudspeaker for monitoring purposes (Final report)". BBC Research Department No. M.008/3, 1952/5 [13] INST. OF CIVIL ENG. pub. 1945. 'Discussion on modern theory and practice in building acoustics'. Engineering Division Papers 1753-7797. Exact date of quote unknown but by implication, post war, 1945. "Mr. H. L. Kirke observed that are the subject of acoustics had received too little attention, except by a very few, and it was still understood only by the few. Before the war the Acoustics Department of the BBC had carried out some experiments into studios which had more or less at the same shape but had different wall surfaces, one being irregular and the other regular; and it had been found and that, although the two studios, of identical acoustic treatment, had exactly the same rate of decay or reverberation-time, there was a vast difference between the sound that came to the ear from the two studios." [14] The intense rivalry between the competing Baird and EMI TV systems is described here. Kirke must have demonstrated remarkable political and technical ability to navigate the BBC through to selection of the best (i.e. highest performance) system. The commercial advantages and prestige to the winning format supplier were huge. Also here the BBC examines rival TV systems. [15] Kirke's visit to USA - reference to follow [15A] US Dept. of Justice, 31 Jan. 1944, 'List or manifest of alien passengers for the United States'. Kirke is detailed on List 4, as 'Occupation: radio engineer' amongst eighteen government officials and one marine engineer. At that time of WW2, the liner Queen Mary was commandeered by the British Government. One can only marvel at prospect of stimulating conversations between diplomats and the two engineers. [15B] Sailing to the USA in late early February 1944 from the UK was not risk-free because althougth the U-boat threat had receded, it had not disappeared. [16] Peter Goldmark, pioneer of the LP record launched 1948. He was turned down by Baird for a job after meeting Baird for lunch in London [17] McLACHLAN N.W., 1934. 'Loud speakers - Theory, Performance, testing and Design' [18] BBC/KIRKE, H.L., 1945 'Improvements in and relating to PA systems ...' UK patent GB588355 588,355 [19] SHORTER D.E.L., 1946. "Loudspeaker Transient Response: Its Measurement and Graphical Representation," BBC Quarterly, vol. 1, pp. 121-129. Waterfall plots. [20] BRIGGS G.A., 1948. 'Loudspeakers. The Why and How of Good Reproduction' 1st Edn. [21] HARWOOD H.D., 1968. "New B.B.C. Monitoring Loudspeaker" Wireless World magazine [22] SHORTER D.E.L., 1950. "Sidelight on Loudspeaker Cabinet Design". Wireless World magazine [23] UK Patent 696671 'Improvements in and relating to Loudspeakers'. Application date :23 Sept. 1949. Published: 9 Sept. 1953 BBC/Donovan Ernest Lea Shorter [24] COOKE, R.E., 1968 "High Quality Monitoring Loudspeakers" British Kinematography Sound & Television Journal. [25] OLSON [26] SHORTER, D.E.L., 4/1958. "A survey of performance criteria and design considerations for high-quality monitoring loudspeakers" I.E.E. Paper [27] NOVAK James F., 1958. "Performance of Enclosures for Low Resonance High Compliance Loudspeakers" Journal Audio Eng. Society, presented New York --------------------- For editing: [XX] BRAY, John, 2002 'Innovation and the communication revolution' IEE ISBN 0852962185 In Memoriam Obituary: D.E.L. Shorter Obituary: James Moir Obituary: H.J. Leak Obituary: P.J. Baxandall * © Alan A. Shaw, 2008. This article has involved my careful research, and as further information becomes available I will add it. Please email me for permission to use my words.
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