PT mixer headroom severely reduced to 20dB over 0dBFS. Bug?

[Tweakhead]

Originally Posted by JFreak

You also got Big Sur support and it is likely you would get M1 support this year too. Nobody knows but once Avid drivers are good to go I bet PT will be native as well

yeah, just in time for M2 coming out.

news link.

[JFreak]

Originally Posted by Tweakhead

yeah, just in time for M2 coming out.

news link.

Well we do not know what they call the next chip. If this M means "model" then it is surely M2, but if it means "mobile" then the next chip would probably be D1 as in "desktop". Either way, I was talking about native Apple Silicon drivers and software.

[JFreak]

Originally Posted by JFreak

Well we do not know what they call the next chip. If this M means "model" then it is surely M2, but if it means "mobile" then the next chip would probably be D1 as in "desktop". Either way, I was talking about native Apple Silicon drivers and software.

So lame to quote myself, but hey.. just a joke.. if they created a "realtime" processor series and "desktop" processor series, they could also combine them on special hardware and we could one day have a "R2-D2" model

[Farhoof]

Originally Posted by Rich Breen

And...the issue here is that there seems to be something wrong with the math in clip-gain and audiosuite processes - it may be an edge-case that it has to be 20dB above full scale to flag it (and it's good that it's not in the actual floating point mixer dsp - that would make it *not* an edge case), but clips should be recoverable to literally hundreds of dB above "full scale". <cut>

Please note it's not just clip gain and audiosuite, it's the mixer as well.

Originally Posted by Franklyn

does anyone know from which version this problem arose?

2018.12 is OK
2019.6 is NOT
so somewhere in between. I already have multiple versions installed for different tasks so I rather not install even more to pinpoint it.

Originally Posted by Wolfgang Eller

Rich, don't get me wrong, I'm completely with you but I'm totally amazed that someone found that bug.

I've found out while testing a new limiter, I have a test session set up with different kinds of limiters pushing it to the max to see how they handle it. It's a session used over the years and I noticed some limiters are now distorting where they previously did not.

I work in post, not in music, so I might have encountered this before, handling a gunshot or something, but could be masked by other layers of sounds and nobody noticed. I highly doubt it's an issue in music, but again, being the floating point mixer, it's still of concern IMHO.

[JFreak]

Originally Posted by Farhoof

2018.12 is OK
2019.6 is NOT

Between that was the HDX voice upgrade fiasco, maybe it had something to do with this?

[Farhoof]

So, 3 years later, the bug turned out to be a hidden feature that apparently nobody knew about. But now we got the option to turn it off.

https://avid.secure.force.com/pkb/ar...eak-Protection

[Fidelis]

Originally Posted by Farhoof

So, 3 years later, the bug turned out to be a hidden feature that apparently nobody knew about. But now we got the option to turn it off.

https://avid.secure.force.com/pkb/ar...eak-Protection

That is unexpected! Nice to know. Wondering why they didn’t say before?

[midnightrambler]

Well as someone who suffered their fair share of super-deafening “blasts” caused by the compensation delay bug in the past, I’m quite pleased this feature is there and enabled by default.

[Darryl Ramm]

Originally Posted by midnightrambler

Well as someone who suffered their fair share of super-deafening “blasts” caused by the compensation delay bug in the past, I’m quite pleased this feature is there and enabled by default.

Have you seen if this actually helps with the noise problems you were having? At least from Avid's description this does not seem to make a lot of sense, or is not really explained well. If it's just filtering +20dBFS signals? Your output can't get louder than 0dBFS. So as always there is lots of potential to get full output/damage stuff without ever exceeding +20dBFS on any internal signal path. Maybe the goal is to trap totally errant plugins writing kinda random output but it's not clear. And seems this won't help with many many sources of loud noises and pops, and if it does help with any in practice they can't be worse at harming your output chain or ears than a 0dBFS signal.

"The" compensation delay bug... I think you mean "a" compensation delay bug, there are clearly many bugs with delay compensation that Avid needs to fix.

[Darryl Ramm]

Originally Posted by Farhoof

So, 3 years later, the bug turned out to be a hidden feature that apparently nobody knew about. But now we got the option to turn it off.

https://avid.secure.force.com/pkb/ar...eak-Protection

Thanks for pointing this out, seems a silly thing for Avid to have done. "Hey we've got a 64-bit mixer and 32-bit float file support but we'll just throw away all that dynamic range... discarding ~570 dB in the 32-bit file or ~5900 dB in the mixer." And yes nobody needs the real upper range, but who knows if they might need to handle a +20.1dBFS signal. I had noticed some of this wonky behavior before but just avoided anything so hot as anybody should, but for Avid not to explain this was awful, and I still suspect the whole idea was not well thought out.

And they don't even explain well what is going on clearly. It's not just say muting the Pro Tools output (I can't tell if it does I'm not going to test), it *is* clipping the signal. You can get 32-bit float files created here with artifacts in them at very high levels (Still <+20dBFS) levels and so what happens when you take that file and play it in something else. Wherever Avid thinks they are doing here is not going to help stop that from causing problems. And combing this with the Pro Tools waveform track UI is broken and does not properly draw signals at high +dbFS values... it's like Avid wanted to claim 64/32 bit float support but nobody actually worked though thinking about the corner cases that are needed to actually make it work really robustly. If only Avid had say the engineering talent of the Reaper team....