[ProAudio] FeralA - Recordings released encoded with Dolby A

[Richard L. Hess]

Hi, Bill,

I got into TV facilities engineering right out of university in 1974 and 
did that full-time until 2004 when I switched over to tape restoration 
which I had started doing in 1998 part time. I could hear the noise 
reduction of Dolby A (properly aligned) but didn't hear the artifacts 
that I hear now once John's magic software removes them, even though my 
hearing was better then, but less trained. I actually had suggested that 
we consider Dolby A for ALL 1-inch type C video tapes as we were 
considering that switch in the late 1970s. Julie Barnathan got me in his 
limo for a ride back to the hotel after the NAB show one day and asked 
me, "What difference am I going to hear on 3-inch speaker." No Dolby A 
on the 1-inch machines. Which, with 20/20 hindsight was probably a good 
idea for archiving and interchange.

It's shocking the number of noise-reduction-encoded tapes that I 
transfer that have no reference. I've gotten very good ad adjusting 
Dolby B by ear. One can hear the mistracking if the overall level 
remains the same and you adjust the machine's output level and the 
monitor level together...it "snaps" into place. Of course, that makes it 
impractical to use the cassette machine's built-in Dolby. I use an 
outboard Dolby 422.

I continue to be amazed at the number of people who don't really 
understand this. If you haven't looked at the 361 manual link, it's 
worth a look as it didn't help ease the confusion, but the rule is the 
Dolby Tone goes to the centre dot on the Dolby meter (though I think 
those meters weren't all that consistent--perhaps why they went to LEDs 
in the 363 (A/SR) and 422 (B/C/S) processors. Sadly those are no longer 
available.

Cheers,

Richard

On 2020-02-09 3:27 p.m., Bill Whitlock via ProAudio wrote:
> I've been reading this thread with great interest - and admittedly 
> cringed at the talk of using A encoding as an "effect" - but I can 
> attest to the ignorance about multi-band "companding" by many 
> mastering engineers.  I was manager of electronic development 
> engineering at Capitol from 1981-1988 and, toward the end saw the 
> mastering people grappling with the differences between mastering for 
> vinyl and cassettes and the "new" CD - lots of opinions and very 
> little science about reference and peak levels. I was never directly 
> involved in the mastering process. Most of my work was developing 
> improved record electronics for 64x cassette duplication (Capitol 
> "XDR" brand) in the factories, including our own implementation of 
> B&O's HX Pro.  In 1988, in our development lab, we were recording 
> cassettes at 64x directly from digital masters (they were amazing 
> first-gen analog).  Anyway, because I understood the physics of 
> magnetic recording, as well as the companding processes of Dolby A and 
> B, I often got called into disputes about reference levels and "Dolby 
> tones" - and the importance of machine calibration tapes of 
> accurately-known fluxivity (185 vs 250 nWb is a big deal).  And, for 
> what it's worth, I had pretty good ears back in those days and could 
> never hear the effects of Dolby A if the signal chain was properly 
> calibrated and set-up. Therefore, I can completely understand the 
> Dolby staff "eye roll" and agree with Bob.
>
> Bill Whitlock
> AES Life Fellow
> IEEE Life Senior
> Whitlock Consulting
> Ventura, CA
> Office (805) 755-5018
>
>
> -----Original Message-----
> From: Bob Olhsson via ProAudio <proaudio at bach.pgm.com>
> To: proaudio at bach.pgm.com <proaudio at bach.pgm.com>
> Sent: Sun, Feb 9, 2020 11:51 am
> Subject: Re: [ProAudio] FeralA - Recordings released encoded with Dolby A
>
> A problem was that Dolby A was designed for 185 nWb. record levels and 
> assumed tape hiss would be present to mask the artifacts. Elevated 
> Dolby levels were a bad sounding mistake. I asked someone from Dolby 
> about this at an AES show. He rolled his eyes and said “Yes, most 
> Americans get it wrong.” A huge proportion of British pop and 
> classical records during the late ‘60s and ‘70s used properly aligned 
> Dolby.
> Bob Olhsson 615-562-4346
> *From: *Richard L. Hess via ProAudio <mailto:proaudio at bach.pgm.com>
> …Working with John on this has pointed out to me how much damage Dolby 
> A coding/decoding did to a recording. Back in the day, my purist 
> recording friend, Don Ososke from San Francisco never used Dolby as he 
> hated what it did to the music. I tried some dbx and found it horrid, 
> but I needed some NR on the choir recordings I was doing, so I sprung 
> for a pair of 361s and used them, but I'm really glad we have that 
> behind us now.
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-- 
Richard L. Hess                   email: richard at richardhess.com
Aurora, Ontario, Canada           http://www.richardhess.com/
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.

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