Rick Krizman, one of the testers that did an analog mix, sent me the following details of his testing.
My job was to test analog summing from PTHD v.5.3.1 through my Trident Series 24 console. This is roughly the same technology as a Series 65, only with 24
buses. Please note this is not a Series 80, nor is it of the same quality.
The console itself is from the mid-80's. Eight of the inputs plus the output
module have been modified by Jim Williams who recapped and replaced the
standard chips with high slew rate video chips. The result, to oversimplify,
is greater clarity and transparency with less of a characteristic Trident
Assisted by Michael Perricone (mixing engineer, former owner of Interlock
post), I set up 16 channels of HD 192 and 8 channels of Apogee AD-8000. We ran
each channel of the session out these converters into the line ins of the
Trident and returned the mix output of the Trident into 2 channels of the HD
192 and a stereo bus in the Protools session. A PAZ meter was inserted on this return bus and the analog fader of each track was adjusted to show the desired -12 level on bus, to within a tenth of a db. When these levels were set we
played the mix and compared it to the phase-reversed summed mix included with the session. At this point eight tracks did not cancel. It turned out that
these tracks were the ones being outputted by the Apogee and that this was a latency issue. We moved those tracks up 14 samples and they cancelled also.
To generate the unity mix we did a stereo-interleaved 24 bit bounce-to-disc
from the return bus in Protools. To generate the variable-fader mix, we
lowered the individual faders in Protools 3 db and then fine tuned with the
analog faders to show a reading of -15 on the return bus for each track. We
then compensated for this reduction by raising the PT master fader up 3 db, and
did the bounce-to-disc. Any dither was from whatever the program automatically
supplies (no plugins were harmed in the course of this experiment).
[ April 07, 2003: Message edited by: 3D Audio Inc. ]
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