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Before we are swept away on waves of nostalgia and AM audiophilia, I would like to balance the comments of some radio old timers who have written to your delightful magazine regarding the potentials and practices of A(ncient) M(odulation). As an engineer for two FM and one AM radio station, I am only too aware of the pressures of the broadcasting marketplace to provide the strongest, loudest, clearest, and brightest signal possible. Thanks to recent FM technology, such as the Orban "Opti-mod" limiter/stereo generator, loudness and fidelity are no longer mutually exclusive entities. Recent state- of-the-art FM exciters, such as the Collins 310Z, have harmonic distortion measurements around 0.08 percent. And with cartridge and stylii combinations like the Stanton 681SE, composite microwave studio-transmitter links, and integrated circuit consoles, it is virtually impossible to transmit a bad FM signal without gross ineptitude or deliberate intention.
On AM, however, we are hampered on every front. FCC rules for AM technical standards permit distortion of 5 percent, noise levels of only 45 dB, and frequency response of ± 2 dB from only 100 Hz to just 5 kHz.
Frequencies 15 kHz away from nominal center carrier frequency must be down 25 dB below the unmodulated carrier level. As to the actual broadcasting equipment in use, I can recite cases of 17 percent intermodulation distortion in a popular brand AM transmitter and have had experiences of horrendous low-frequency phase shift in high level plate-modulated AM transmitters which do not affect harmonic distortion measurements on sinusoidal tones, but completely alter amplitudes and waveshapes of audio signals, causing intermodulation, overloads, and sonic muddiness. Only the very newest all solid-state low-power AM transmitters, such as the Haris 1 kW, have eliminated such problems.
So even if one listener out of 500,000 owns a McKay-Dymek tuner, we cannot as broadcasters supply AM high fidelity due to both equipment shortcomings and the necessity to make our signals heard in a spectrum crowded with stations, man-made and natural interference, and modulation- mad program directors and managers.
The situation is not completely hopeless; it is just that there are inevitable compromises that must be made on AM that do not have to be made on FM and indeed are not made on the FM stations I work for.
Stephen R. Waldee
Broadcast Technical Consultant KSOL San Mateo, Cal.
Victor Brociner died of a heart attack the day before Thanksgiving at the age of 66. During the 30s, he developed a high fidelity, broad-band AM receiver, a low-tracking-force record player, and speaker component system, which set new standards and later was made a part of the Smithsonian collection. In 1937, Brociner founded the Philharmonic Radio Co. with Avery Fisher and a third partner, and after WWII he founded Brociner Electronics. During the early 50s, Brociner produced one of the first integrated amplifiers, a Williamson at 30 watts which was quite powerful for that period, and some of the first high fidelity components using printed circuits. Another product, the Brociner Transcendent loudspeaker system, was noted for its combination of efficiency and high sound quality.
When financial problems forced Brociner to close his company, he did not simply declare bankruptcy, but instead paid off every creditor in full.
Afterward Brociner joined University Loudspeakers, but when that firm moved to Oklahoma, he joined H.H. Scott as Engineering Vice President, working on a variety of products including speaker systems, tuners, amplifiers, and receivers. When Scott ran into difficulties in 1972, Brociner moved to the Avid Corp. as Vice President for Engineering and Stereo Products. While there, Brociner took on responsibilities far wider than one might assume from his title-from conception and basic product design, through vendor selection, production line engineering, and quality control.
In the few short years since the firm was founded, Avid speakers have become one of the industry's accepted lines, largely through the efforts of Victor Brociner.
Brociner was a widely published author, a member of numerous industry committees, a fellow of the Audio Engineering Society and a member of its board of governors in 1955, and a member of the IEEE, the Acoustical Society of America, and the Audio Hall of Fame.
Notes courtesy of James Brinton and Dick Lewis
Four-Channel Programming Dear Sir:
Martin Clifford's article "Syndication of Quadraphonic Radio Programs" in the November, 1976, issue of Audio has performed a service by pointing out to the readers that many FM stations carry quadraphonic programs without fanfare. However, I was surprised that Mr. Clifford's article emphasized the syndication of the Boston Symphony Orchestra programs in the QS mode since I was aware that Richard Kaye of WCRB, Boston, who is manager of the Boston Symphony Transcription Trust, had been syndicating the Boston Symphony Orchestra principally in SQ. I talked to Mr. Kaye, who told me that the story as published in Audio was true, but incomplete, in that of the quadraphonic tapes he distributes, 20 are encoded in SQ and four in QS. Naturally, he will furnish any code requested by a station's sponsor, and it may be well to note that CBS does not sponsor any syndicated quadraphonic programs.
Another statement which needs clarification is the last paragraph relating to the "Live from the BBC" program. When I visited Mr. Rickey Merrett, the transcription engineering manager of BBC, in London last September, he told me that he issues 80 quadraphonic programs per year, of which 90 per are encoded in SQ. A phone call this morning to him confirmed these figures.
I owe Mr. Clifford and the readers of Audio an apology for not having been more diligent in furnishing information about SQ syndication to Mr. Clifford in a sufficiently timely fashion to have avoided any erroneous impression which his article might have created about the significant role of SQ in broadcast syndication.
Benjamin B. Bauer Vice President and General Manager CBS Technology Center Stamford, Conn.
Jaws Disc Imported
I thought you might be interested in knowing that JVC has decided to make the Jaws CD-4 Quadradisc album available in the U.S. To order a copy, you can send $7.00, which includes postage, to: JVC Cutting Center, 6363 Sunset Blvd., Hollywood, Calif. 90028.
Brian A. Moura, Hayward, Calif.
I am in charge of developing a student audio engineering library. If you have any literature concerning audio engineering, electrical engineering, music, physics, or other subjects appropriate to the audio field that you no longer use, their donation would be greatly appreciated.
Usable printed matter would include periodicals such as Audio, db The Sound Engineering Magazine, Audio Engineering Society Journals, Recording Engineer/Producer, Studio Sound, etc., plus textbooks, service manuals, charts, and photographs.
Out of date or obsolete materials all have their value in student learning situations and anything will be welcome.
Thank you for your interest in further promoting education in the audio field.
The Student Library c/o T.W. Woynicz P.O. Box 7347 Hollywood, FL 33021, USA.
Dear Sir: I have just read your feature article "Nothing New Under the AM Sun" by Michael N. Stosich in the January, 1977, Audio with extreme interest. I happen to own an E.H. Scott 30-tube Philharmonic receiver as well as the 23-tube All Wave High Fidelity Receiver, an earlier model. Because of this excellent article I am renewing my subscription to Audio. For years I have wanted to track down the history of E.H. Scott and his radio laboratory, but never quite got around to doing it. This article was an answer to my prayers, to say the least.
I purchased both Scott receivers used and in need of repairs. I have the John Rider service manuals on both sets, and having been in the audio service business for more than 31 years, I agree that it takes more than an amateur to repair them. I know of nothing that can be added to what Mr. Stosich said, as he put it perfectly.
Lawrence M. Henry, North Platte, Neb., USA
(Source: Audio magazine, March 1977; )
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