Re: [ARSCLIST] RIAA EQ software

[Bob Olhsson <olh@xxxxxxxxxxxxx>]

They were still available and in common use in the '70s. I suspect the 7"
test records were first released in 1949 along with the 45 RPM records.
According to Wikipedia the New Orthophonic curve was disclosed in a
publication by R. C. Moyer of RCA Victor in 1953.


Bob Olhsson Audio Mastery, Nashville TN
Mastering, Audio for Picture, Mix Evaluation and Quality Control
Over 40 years making people sound better than they ever imagined!
615.385.8051 http://www.hyperback.com    http://www.thewombforums.com


-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:ARSCLIST@xxxxxxx] On Behalf Of George Brock-Nannestad
Sent: Tuesday, August 26, 2008 4:51 PM
To: ARSCLIST@xxxxxxxxxxxxxxxx
Subject: Re: [ARSCLIST] RIAA EQ software

From: Patent Tactics, George Brock-Nannestad

Bob, you wrote:

> -----Original Message-----
> From Eric Jacobs: "Weren't all those math formulas and standards the basis
> of the RCA test record?"
> 
> In terms of public dissemination, the test record predates all of them
> that
> I'm aware of although no doubt there was some sort of internal
> documentation
> at RCA. 
> 
> The 1953 standard specified a series of 23 frequencies ranging from 30 to
> 15k. as is found on the test record. This was only later described as the
> 3180, 318 and 75 microsecond time constants so the RCA test record may
> well
> have been the basis and not the other way around. 

----- well, on the cover of my 10" record, next to the equivalent LR, and 2x

RC networks are given the time constants you mention. The text reads:

"The 'New Orthophonic' characteristic (relative stylus velocity vs. 
frequency) may be expressed as the algebraic sum of the ordinates of three 
individual curves which conform to the admittances of the following networks

expressed in dB". 


My record is not dated, and I would be interested to know the date.

Again it should be the
> basis of any attempt at accurate reproduction simply because it was what
> everybody trimmed the response of their cutting systems to match. How
> right
> or wrong the RCA test record is doesn't matter.

----- you are absolutely right and in accordance with the instructions on
the 
record. If this record was widely distributed, obviously that WAS the 
standard.

Kind regards,


George