[ProAudio] FeralA - Recordings released encoded with Dolby A

[Bob Katz]

Here are three responses to three different subjects that have expanded 
from the original topic!

I. There are so many ways that test tones at the head of a tape could be 
different from the audio on the tape. In the old days in some studios I 
saw some visiting engineers lay down test tones after the fact, on a 
different machine than was used for the mixdown, as if that would help 
the situation.

We transfer engineers have developed a spidey sense and often check and 
recheck the content to ensure it has not changed from cut to cut. On 
most machines, before making the transfer for a new cut, you can put 
your finger on the side of the tape to tilt it slightly, while listening 
in mono to ensure the azimuth has not drifted, and then transfer the new 
cut.

II. As for Bob O's comment against the practice of doing elevated dolby 
level, I agree there was a standard for 185, but as people started to 
use elevated levels as high as 6 dB over 185, I was seriously concerned 
about running out of headroom in the Dolby gear if standard dolby level 
was used, and so as a practice, I see less harm in using an elevated 
dolby level than to overload the Dolby processor with too hot audio. I 
always recorded dolby tone as well as 1 kHz @  VU. The Dolby 361 meters, 
as Richard mentioned, were notoriously inaccurate, I would put a sharpie 
mark on the real dolby level on the meter, for what it was worth. There 
was a Dolby tester that could be used for accuracy of the dolby tone or 
I believe a test point that could be checked.

III. Dear John:

So you set azimuth by looking at the bias. Are you looking at two 
channels of bias? And how is this superior to the tried and true method 
of mono-summing the left and right audio channel and adjusting for 
maximum high frequency response, also checking by inverting the polarity 
of one and going for a minimum as a cross check?


Best wishes,



Bob

On 2/9/20 4:32 PM, John Chester via ProAudio wrote:
> On 2/9/20 3:56 PM, Richard L. Hess via ProAudio wrote:
>
>> Also, a funny story, the tones at the head of that master tape caused 
>> Alan a bit of a challenge...the azimuth of the tone didn't match the 
>> azimuth of the audio!
>
>
> Been there, seen that.  An assembled album master may contain cuts 
> that were recorded on different machines, and sometimes even in 
> different studios.  This becomes really obvious when I'm doing 
> Plangent transfers.  I can see when the bias frequency and flutter 
> profile change, and I set azimuth on each cut by looking at the bias.  
> I have seen a master where the head tones were recorded on a different 
> machine which didn't match *any* of the music.
>
> When the album master is Dolby encoded, and several different machines 
> were used for mixing, I can't believe that the Dolby setup on all of 
> those different machines perfectly matches the head tones.  
> Fortunately the tape with the head tones recorded on a completely 
> different machine wasn't Dolby.....
>
> -- John Chester
>
>
>
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-- 

If you want good sound on your album, come to Bob Katz 407-831-0233 
DIGITAL DOMAIN MASTERING STUDIO Author: *Mastering Audio* Digital Domain 
Website <https://www.digido.com/> No trees were killed in the sending of 
this message. However a large number of electrons were terribly 
inconvenienced.

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