From: Doug Pomeroy <pomeroyaudio@xxxxxxx>
Date: September 30, 2008 8:51:10 PM EDT
To: 78-list <78-l@xxxxxxxxxxxx>
Subject: Re: Peter Copeland on RCA Victor recordings (1941)
Clarification:
I only mentioned that issue of Wireless World, because it is
Copeland's
Ref. 60, which he identifies at the head of the paragraph which
includes
the statement about Victor's use of limiters. Thanks for checking.
Doug
Date: Mon, 29 Sep 2008 15:14:11 -0400
From: Michael Biel <mbiel@xxxxxxxxx>
Subject: Re: Peter Copeland on RCA Victor recordings (1941)
Prentice, Will wrote:
Doug and all
I've looked up this edition of Wireless World, but there's no
mention of
Victor's use of limiters I'm afraid. It's a short, 3 paragraph
article
entitled "New Recording Characteristic: Reducing Noise Level"
describing
in general terms the idea behind pre-emphasis.
I think the key word here is the use of the word "level" in the
headline. Since limiters adjust level, could he have
misinterpreted it
to mean that this EQ was adjusting levels? As we know now, a
pre-emphasis properly works only if there is a calibrated reciprocal
de-emphasis on the playback end. Consumer phonographs did not have
actual de-emphasis circuits at that time, only professional
turntables
in broadcasting had them for the newly emerging Orthocoustic and NAB
curves. Unlike Dolby and DBX, these units were completely
passive. Was
Peter possibly claiming that RCA was using limiters as an active EQ,
several decades in advance of Dolby? And what was the 1941 Wireless
World article detailing? Orthocoustic had been announced back in
1938
for ETs. Was this a curve being used on commercial phonograph
records
or a belated article on Orthocoustic?
I don't recall discussing this with Peter, but others he worked
with on
a wider level may know his sources. George Brock-Nannestad,
possibly?
Will
I agree. George, have you seen anything in the EMI papers that
discuss
this?
Mike Biel mbiel@xxxxxxxxx
-----Original Message-----
From: Doug Pomeroy
The following from Copeland's manual has always puzzled me, and I
wonder
if anyone can shed light on the reference to "Victor's then-unique
use of multiple
limiters (essentially one on each mike)", since I've never heard of
this from any other
source. This may originate in Ref. 60, Wireless World (1941), which
I have not
seen. RCA Victor may have experimented with limiters in 1941, but
Copeland's
statement can leave the impression that this was common practice.
6.71 Various RCA characteristics
Ref. 60 (July 1941) is the earliest contemporary reference I have
found which describes RCA Victor using pre-emphasis on its 78s,
although the time constant was not given. Straight listening
suggests the idea was tried somewhat earlier, and we saw in section
6.23 that Moyer wrote about RCA's Western Electric systems with
pre-
emphasis at 2500Hz (corresponding to 63.6 microseconds); but I am
deeply sceptical. It seems to me far more likely that, if something
which had been mastered direct-to-disc was reissued on microgroove,
the remastering engineer would simply have treated everything the
same. And I consider it likely that judging by "pure sound" clues,
Victor's then-unique use of multiple limiters (essentially one on
each mike), would itself have resulted in a "brighter" sound.
Doug Pomeroy