Why does Proo tools sound different at times?

[Mixchump]

Originally Posted by Wolfgang Eller

You ever did a phase cancellation test?

Doing a null-test between two PCM files that have both suffered the same loss will yield a null down to infinity.
Printing a mix to DSD and comparing to the PCM print to DSD of the same reveals a difference when inverting in a DXD session. Would love for a scientist to tell us what is happening, but seems to be in the time domain.
Clearly, the work on digital audio is not done...

[K Roche]

Originally Posted by bonzerboy

What i mean is it seem like when bouncing down to a stereo fil it doesnt sound the same as before the bounce. My question is would it be best to print a stereo track for the master and then Print the Master. Then bounce track to dither if going lower bit rate. Hope it makes sense. In Short is it beter to print everything till no plug ins and then bounce?

More info needed
To clarify when you:

Record in (say) in 24 bit 48k WAV
Bounce to Disk in 24 bit 48k WAV to desktop interleaved stereo.
Drag WAV from desk top back into original session, creating a new stereo Audio track

Then A/B the Master Output from session and the New Audio track and it sounds different ?
If so,,, then you Null test them and find they do not null ?

[bonzerboy]

Not talking about mp3's.. I appreciate the feed back from everyone

[bonzerboy]

Most of the time I sum everything to a master buss and record /print it to a stereo track. I think I will try doing that as well as printing the Master be
fore bouncing.

[cwsand]

Originally Posted by albee1952

Speaking strictly of bouncing a wave file, The only time I have ever heard a difference, it was traceable to a fixable cause within the session.

As for it being a well-documented issue, I know of at least 30 audio pro's with multiple grammy's and other awards and all use Pro Tools, yet not a single one has ever mentioned this

I agree - my bounced mixes have never sounded different to me than playing the session, unless there's a routing issue or reverb tail getting cutoff.

Originally Posted by Wolfgang Eller

You ever did a phase cancellation test?

Doing a polarity (not phase) cancellation test is a great idea too - it would cancel out all identical elements and expose anything that's different between the 2 sources.

[Ben Jenssen]

Originally Posted by albee1952

Speaking strictly of bouncing a wave file, The only time I have ever heard a difference, it was traceable to a fixable cause within the session. In my case, there was a bus with the same name as my main outputs(no idea how it happened). Any track that was using this bus as its output was heard during playback, but was missing from the bounce. Once I discovered this and changed those tracks to feed the output, the bounce sounded exactly as the session playback.

The only other thing that comes to mind is, how you playback. For instance, some programs(like iTunes) and some audio cards(computer audio) might have EQ or other "enhancements" that the user may not know about. Most of my playback is done with Windows Media Player, and I have made sure that it is not using any of that junk. I also am feeding that out via optical SPDIF(the mini TRS analog out tends to sound like crap). I can A/B session playback and WMP playback(of the bounced file) and there is no apparent difference.

As for it being a well-documented issue, I know of at least 30 audio pro's with multiple grammy's and other awards and all use Pro Tools, yet not a single one has ever mentioned this

Same here.
Except the Grammy award winners...
Never had a reason to doubt a bounce or a print in 20+ years.

[JFreak]

Originally Posted by Wolfgang Eller

You ever did a phase cancellation test?

That is total BS if you ask me. Unless you have a mix without any kind of modulation (reverb) whatsoever.

Some PT builds have had bugs with plugin latency compensation and those bugs are hard to pinpoint where it started and what caused them. But they are bugs Avid takes seriously. It just takes time to squash them.

Long story short, try another PT version and see if your problem goes away.

[EGS]

Originally Posted by bonzerboy

...it doesnt sound the same as before the bounce...

If you are careful about Pro Tools routings etc, monitoring etc, an offline-bounce sounds the same as the source. Record/bounce/master @ 24/48 wav. Central Station (or other) monitor switcher to check bounce playbacks.

[Bookerv12]

Originally Posted by bonzerboy

Most of the time I sum everything to a master buss and record /print it to a stereo track. I think I will try doing that as well as printing the Master be
fore bouncing.

Hi,
You mean you sum using an aux?
Once you print to a stereo track, no need to bounce. It is a bounce.
Export the stereo track. (The clip on the stereo track)

[cwsand]

Originally Posted by JFreak

That is total BS if you ask me. Unless you have a mix without any kind of modulation (reverb) whatsoever.

Some PT builds have had bugs with plugin latency compensation and those bugs are hard to pinpoint where it started and what caused them. But they are bugs Avid takes seriously. It just takes time to squash them.

Long story short, try another PT version and see if your problem goes away.

I just bounced a mix and pulled it back into the session all (48k/24bit) and reversed the polarity - it didn't cancel everything completely, just lowered the overall volume a bit and the high frequencies are fluttering. I can understand some things like DC or effects that might not start the oscillation at the same time, but I would have thought there would be a lot less of the overall mix still present. Interesting.