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