tracks are sliding out of time

[dendee]

recently installed an airport card. prior to this, i mixed a track and everything played back ok.. in time. when i opened the same file today, things weren't lining up properly. suddenly the bass track was very rushed and the guitar was late compared to the drum kit. i ran disk utility and secure empty trash but same problem continues. the only difference was i had an airport card installed after doing the first mix, but i "turn airport off" when using protools. could the mere presence of an airport card take away that much resources to cause the timing of tracks to get screwed up?

7.4.2 HD3 pcie
Digi 192
macpro 2.8, 6 gig ram, 8 core processor (all new in september 08)

7 processors on, delay compensation on highest setting, voices at 3-96,buffer 2048

[KingFish]

Even though Delay Compensation is set to Long in the Playback Engine settings, you sure you have it ON at the Bottom of the Options menu? in the menu Bar ? you should see a "Dly" icon in Green below the Counter in PT

[crizdee]

Originally Posted by dendee

recently installed an airport card. prior to this, i mixed a track and everything played back ok.. in time. when i opened the same file today, things weren't lining up properly. suddenly the bass track was very rushed and the guitar was late compared to the drum kit. i ran disk utility and secure empty trash but same problem continues. the only difference was i had an airport card installed after doing the first mix, but i "turn airport off" when using protools. could the mere presence of an airport card take away that much resources to cause the timing of tracks to get screwed up?

7.4.2 HD3 pcie
Digi 192
macpro 2.8, 6 gig ram, 8 core processor (all new in september 08)

7 processors on, delay compensation on highest setting, voices at 3-96,buffer 2048

Usually happens when the buffer is changed between sessions!! make sure its on the exact setting it was when the track was mixed.

Chris

[KingFish]

Originally Posted by crizdee

Usually happens when the buffer is changed between sessions!! make sure its on the exact setting it was when the track was mixed.

Chris

Geeze, that's a scary bug if I ever heard one... I've had the "Sloppy Sessions" before, maybe in 7.4 --> earlier and trashed Prefs, rebooted, and cranked the Playback Buffers to "Sort it out" - without really knowing "What was causing the problem.

Our (I assume most of the Pro-Tools HD Community) Playback engine settings constantly change, as outside sessions come in, more DSP is needed for Voice Allocation, VI's and RTAS are added etc....

It's probably a good idea to document your Playback engine settings, with a Heavy Mix Session, although I've had none of these problems on 8 (Yet), I DO remember this happening once on 7.4 - the session sounded REALLY drunk.

Hopefully "They got it" in 8 - I've had some seriously massive Mix sessions over here, and my Playback engine probably changes every day, and I haven't had this problem so far (Been on 8 almost 6 months)

[crizdee]

Originally Posted by KingFish

Geeze, that's a scary bug if I ever heard one...

That's no bug! thats the way it is if you change the buffer "after" plugins have been inserted and the mix is on its way!! Really noticeable when more RTAS plugs are used and especially when they are inserted after TDM plugs.

Chris

[KingFish]

I'm Sorry Chris, I was reading too much into the phrase "The Exact Buffer Setting" in your last post. And confusing the "Real Issue"

Raising the Buffer, will often bring a Mix engine "Out Of Range" of the Delay Compensation Setting"

However, A session Mixed at 64 samples "MAY" have the buffer changed to 1024 with absolutely NO sonic or timing difference, as long as the track delays, aren't reporting "Out of range" (Red)

Even "Creating that exact session" with identical plugins per track, STARTING OUT at 1024 - would take you outside the range of delay compensation.

You could then, either Lower the Buffer setting, or if you're on the "Small Setting" change the delay Compensation to Long.

I do agree, that if I take a heavy Mix session, that was mixed at 64 samples or 128 and change the playback buffer to 2048 - it'll completely destroy the timing of the session, but the results will appear in the Track DLY dialog - and can return to it's "Normal state", using a few different settings, btwn Buffer, and Delay Compensation.

[dendee]

i did change the buffer between sessions. i'm constantly switching..i have to in order to have minimal latency for recording. but for playback, i increase it again. i thought those settings were saved with the mix..?

to correct the timing problem, i tried changing the buffer and number of voices etc, but i still cant recreate the timing accuracy of the original mix.

yes, it's a big mix with lots of plugs, but it's an HD3 system!

what do we have to do in order to have tracks play in time with each other? this is insane. now i dont trust protools and i'm looking at my tape machine with envy. would an apogee big ben solve this problem?

thanks to all.

7.4.2 HD3 pcie Digi 192
macpro 2.8, 6 gig ram, 8 core processor (all new in september 08)
7 processors on, delay compensation on highest setting, voices at 3-96,buffer 2048

[KingFish]

Hey Den, it "Did" or "Was supposed to" save your Mix Engine settings with the session, perhaps it was changed by mistake, corrupt Prefs, and reSaved.

Nevertheless... try setting your Playback buffer at it's LOWEST setting (That 2048 is killing you) (Probably 128 in PT7.x) and the Delay Compensation to it's Highest setting, and increase the DSP for the current voice count (If you can) ie.. if it's 2DSP's at 96 voices, try 3DSP 96 Voices

Then, in your Mixer window, View Track Delays

Any of them Red? Are they RTAS? if so can you convert them to TDM?

[crizdee]

Originally Posted by KingFish

Hey Den, it "Did" or "Was supposed to" save your Mix Engine settings with the session, perhaps it was changed by mistake, corrupt Prefs, and reSaved.

No the playback buffer is set overall and is not saved with sessions! same for the amount of DSPs assigned to voices.

As we have said The OP's original problem can only be the playback buffer has changed from the time the session was originally mixed.

The buffer must be set to the exact same setting it was when the session was originally mixed and all the plugin combinations were applied and the ADC calculated the session for that combination of plugins.

Regardless of whether the plugins are within range of the delay compensation!!! if you have inserted RTAS after TDM plugins and mixed and matched TDM and RTAS etc, opening this session with another playback buffer setting will now play out of time. i have experienced this many times when i forget i changed the buffer for another session.

Chris

[KingFish]

Originally Posted by crizdee

The buffer must be set to the exact same setting it was when the session was originally mixed and all the plugin combinations were applied and the ADC calculated the session for that combination of plugins.

Regardless of whether the plugins are within range of the delay compensation!!!

Chris

Sorry Chris, don't mean to be argumentative, I guess the fuel for my argument is that they seem to have fixed this in PT8, and I can't test in 7.4.2 where the OP is having problems, I "Thought" it was the same, in 7.4, I've only been "Mixing at Home" on HD "Starting w/ PT8.

In PT8 when you change HW Buffer, the entire Mixer, Re Calculates All Delay Compensation, as long as you are "In Range" as I said above, your Phase coherence and timing wont be effected at all, across several Buffer settings.

HERES A MOVIE OF PT8 RECALCULATING DELAY COMPENSATION ACROSS 4 DIFFERENT BUFFER SETTINGS with all 4 settings "Nulling" in a Phase test, UNTIL the Mixer is beyond Delay Compensation.