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Old 10-04-1999, 01:02 AM
Monte McGuire Monte McGuire is offline
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Join Date: Dec 1969
Location: Malden, MA USA
Posts: 292
Default Re: Pro Tools Sound Quality???

Mr. Rockwell,

Thanks for taking this subject seriously. I really look forward to such a test, but I'd like to make a few suggestions as to how to approach the whole thing.

The problem I have with the sound of the PT mixer happens when I have a large number of inputs summed to mix. It's not that the PT code is misbehaving in some sort of bug like way with large mixes, I think it's simply a case that emphasises the problems with the current mixer. So, any test files made with the two mixers should be made from a typical large scale mix, and not just a few tracks run through the mixer.

The tracks themselves should be sourced through a reasonably clean chain too. If a number of plug ins that round or truncate back to 24 bits are used as inserts on each channel of the test mix, the importance of the final truncation at the end of the stage will be minimized and any differences won't be as audible. We'd simply be comparing twice damaged audio to thrice damaged audio and yes, the differences won't be that significant. So, restrict plug in usage to those plug ins that do 48 -> dither to 24 processing only.

I'd also like to suggest that you use artificial reverb in the mixes. Reverb gets altered by truncation pretty readily, and it's therefore a good test of processing quality for both the aux send mixers and the main stereo mix. Truncation at either end will shrink and harden the sound of the reverb.

Finally, I would prefer it if you could post two unidentified mixers instead of the mixes themselves. You know, mixer A and mixer B and let us decide whether we can hear differences and decide which is which. I guess it would be readily apparent which mixer is which if you looked at allocator, but maybe there's some way to make the non dithered mixer out of the dithered mixer by patching out the dither code. In this way, the two mixers would use up the same DSP resources and be indistinguishable except for their processing quality.


Again, thanks a lot for taking this seriously!! I look forward to the tests...

Monte McGuire
mcguire@world.std.com