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Carl, your observations do ring true; however I believe one of the drivers for rule relaxation was the improvement in performance and reliability of broadcast equipment. If you stopped to measure the performance of today's equipment it would usually meet and often far exceed those often-primitive technical requirements; particularly with respect to audio performance. Even AM radio could transmit 15 kHz. So there really was no point in repeatedly demonstrating compliance with those requirements (other than those valid rules governing the RF envelope and interference). The sad thing is that even with a fairly linear transmitting facility, broadcasters choose to mangle the audio spectral balance, dynamic range and stereo separation with processing gimmicks. Therein lies the rub. Regards, Mark Durenberger -----Original Message----- From: Carl Pultz Sent: Wednesday, September 30, 2015 9:18 AM To: [log in to unmask] Subject: [ARSCLIST] Radio sound Wish I could remember more details about this, which a few of you must know better - as a kid I thought about becoming a broadcast engineer. Decades ago, the FCC required broadcasters to submit regular measurements of their station's performance. These were first to prove that the signal was stable at the proper frequency, power, pattern, and not exceeding limits of modulation. This was important in the days of tube type equipment, which was more subject to drift and change in performance than later, solid state gear. It also acknowledged the nature of commercial enterprise, where maintenance would be minimized and the ultimate internal concern was simply if the station was on the air. But, regulation went beyond that basic aspect and required proof of the quality of performance. Stations (IIRC) had to run distortion, S/NR, and bandwidth measurements to show they were maintaining quality benchmarks. The principal was that operators were given a monopoly to use that piece of public property, so they should be compelled to give the public service of a decent technical standard. I see all claims of the decline of public interest in radio within this context. These requirements were lobbied away and, beyond issues of mutual interference, stations are no longer burdened with such concerns. The market is to regulate, with observable results, providing another example of the doleful consequences of that primitive philosophy. -----Original Message----- From: Association for Recorded Sound Discussion List [mailto:[log in to unmask]] On Behalf Of Dave Burnham Sent: Monday, September 28, 2015 10:42 PM To: [log in to unmask] Subject: Re: [ARSCLIST] a piece of Minneapolis Symphony and Mercury Records history Theoretically AM broadcasting should be capable of a 5k bandwidth. I think back in the '30s and '40s, compression was achieved by manually, (and I would say expertly), manipulating the level on the fly so that the result was a sensation of hearing the full dynamic range of the program. The producer, with a score, would guide the engineer to anticipate a loud entry by gradually reducing the level so the change isn't noticeable but then the sudden loud passage carries the full impact. Automatic gain control could never match this effect. This, of course, was developed when AM was the format of the day. Balancing for 78 rpm discs required a similar procedure. db