Inconsistent Tempo/Playback slows down,speeds up

[perfectdrug6]

Hi everyone,

I'm running Pro Tools 8.0.1cs2 on a powermac G5 dual core 2.3ghz, OS X 10.5.8. The problem is the playback cannot hold a consistent tempo, so if I'm trying to create a drum loop, whether it be audio or midi, fully quantized or not, I can't retain the groove, rhythm. I can see the fluctuations clearly in the main counter or big counter, bars go slow then fast, and it seems completely random, even on a completely blank brand new session. I'm not getting any error messages. I'm not sure if this like a sluggish playback that catches up at various points or what. Any advice greatly appreciated, if you need any more info, please let me know.

Also I'm on a digi 002, lacie extreme triple interface external HD for recording, everything connected 6 pin firewire. Internal clock on PT. No third party plug ins, just what came with Pt.
I've tried:

- reinstalling OS and pro tools
- repairing disk permissions, repair disk
- changing firewire cables
- different h/w buffer settings, sample rates, all kinds of preferences
- trashing prefs

[Bob L]

How much RAM on this G5? Is this a new issue or has it always behaved like this? If a new issue, what's changed (software additions, updates)?

Bob

[perfectdrug6]

Hi Bob,
I've got 4gb of ram. I'm not really sure when it started, I just know I noticed it a couple months ago, because I've been very focused on creating tight drums, and realized I can't create a loop that is consistent. When you watch your main counter time, does it remain completely constant or do you notice, especially if your watching the smallest increments, that it fluctuates at all?

[perfectdrug6]

I have changed my main hard drive about 6 months ago, but it is the exact same model as the original hitachi that came with the G5, but it seems to be working fine.

[Bob L]

Originally Posted by perfectdrug6

I have changed my main hard drive about 6 months ago, but it is the exact same model as the original hitachi that came with the G5, but it seems to be working fine.

Did you reinstall PT, etc., or migrate?

[perfectdrug6]

This is happening on brand new sessions, no instruments at all. Happens no matter what buffer size, and yeah I've tried it on one processor, same thing. I reinstalled everything OS and PT. I've tried disabling blue tooth, airport.

[Bob L]

Originally Posted by perfectdrug6

Hi Bob,
I've got 4gb of ram. I'm not really sure when it started, I just know I noticed it a couple months ago, because I've been very focused on creating tight drums, and realized I can't create a loop that is consistent. When you watch your main counter time, does it remain completely constant or do you notice, especially if your watching the smallest increments, that it fluctuates at all?

The only times I've seen fluctuations could be traced to heavy system loads, or to inappropriate Setups.

4 Gb RAM isn't a lot, depending on the specific VIs in use, and the number of them running. What do you have instantiated, including any that are in Bypass when you see this behavior? If you show Windows>System Usage, what kind of loads are indicated?

What are the settings in use for Buffer Size and Number of Processors? If you aren't actually recording, does it behave better at the highest Buffer? Have you set the number of processors to one less than all available?


Bob