[BC] Re: Could our concept of audio be all wrong?

[Gary Schnabl]

> From: Mark Humphrey <mark3xy at gmail.com>
> 	<74b029b80903130505r2b99489bhb8ccb5a867be3f64 at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Letter of the law from 73.317(e):
>
> Preemphasis shall not be GREATER (emphasis added) than the
> impedance-frequency characteristics of a series inductance resistance
> network having a time constant of 75 microseconds.
>
> So as I read it, 50 or 25 microseconds should be completely legal.
>
> Mark
>
> On Fri, Mar 13, 2009 at 6:28 AM, Milton R. Holladay Jr.
> <miltron at mindspring.com> wrote:
>   
>> If I were king of all media/the FCC/the world, pre-emphasis would be backed
>> off to 50 microseconds (maybe even 25) as well as what you suggest.( People
>> with old radios could turn up the treble.) ISTR that you have discussed the
>> benefits of this some time ago...................
>>     
This preemphasis/deemphasis brings back to my memory a little oversight 
on my part back around 1966 or 1967. Another chief engineer at a 
different station in Milwaukee asked to borrow our Marti (which 
unfortunately would not be available for him) for a short remote link 
for covering a sock hop near UW-Milwaukee--a somewhat popular sideline 
business gig for relatively low-paid DJs back then. His station would 
pick up that feed that Friday or Saturday night for a few hours for a 
change-of-pace programming experiment. [FM broadcasting had few 
listeners back then and even fewer sponsors... Many programs were run on 
a "sustaining" basis.]

Instead, I suggested he whip up his own bootleg 2E26 FM rig and plunk 
that in a quiet spot in the FM broadcast band. I drew up a suitable 
schematic for him and even contributed the 2E26. Within a couple hours 
he had it up and running, probably powered with a power supply from an 
old TV set, as my memory goes.

Pumping the signal into a TV antenna worked FB for that remote link of a 
mile or so. But the oversight entered when I forgot to add any 
preemphasis for the modulation. The Scott FM tuner at their studio end, 
of course, supplied the customary deemphasis, leaving a hole in the 
high-frequency response. Still, it worked alright, and nobody complained...

The DJ at that particular 1960s sock hop was a somewhat skinny Robert 
Collins, as I remembered him then, before his later WOKY-Talky 
talk-radio days, when I drove by the sock hop and saw that the 2E26 was 
operating OK for that station's remote. Collins was a top-30 DJ back then.
-- 

Gary Schnabl
2775 Honorah
Detroit MI 48209