[chrisindc]

My Pro Tools rig (detailed below) works perfectly except when I try to use certain virtual instruments plugins that require MIDI control. I can play/record about two measures of music before everything stops and throws an error (detailed below). The session doesn't crash, and PT doesn't crash, which is good, I guess, but those errors happen every time I use the following virtual instrument plug-ins:

EZ Drummer
M-Audio Keyrig
Arturia Minimoog V

However, I can use the following virtual instruments with no problem:

Sampletank (came with Pro Tools)
Reason LE (came with Pro Tools)
M-Audio Drum and Bass Rig
M-Audio M-Tron

Also, all effects plugins that came with PT work fine.

My Mac's activity monitor shows that the processors seem to max out whenever I use the offending virtual instruments. I thought maybe my Firewire activity might be draining the processors, but I've whittled my FW use down to two inputs -- my Digi 002 control surface, and whichever Oxford 911 chipset drive I happen to be using at the time. I used to have a FW PCI card hub installed, but I removed that thinking it might be part of the problem, and it had no effect. I'm using the FW ports on the back of my G4 Mac and I'm still getting the same errors.

I recently upgraded from Pro Tools 6x to 7.4.2, and also from OSX 10.4 to 10.5.4, but I was having these exact same problems with the exact same virtual instruments before.

I have performed all operations suggested in the DUC General Troubleshooting guide, several many times (including uninstalling/reinstalling Pro Tools, and even the OS X a couple of times just to be sure. I downloaded the Tech Support folder linked to from the DUC Troubleshooting Guide and following all instructions/troubleshooting in there, too, to no effect.

Does anyone have any thoughts/suggestions/experience that could help me get to a point where I can use these virtual instruments? Again, it's my impression that these virtual instruments cause a massive processor drain, while similar virtual instruments seem to work fine. Am I taxing my FW bus too much? Am I having some other kind of through-put problem? Is it possible that one of my dual processors isn't working, or isn't optimized (and, if so, how can I check/fix that)? Is this a clock source issue?

Thanks for reading. Here are the various details:

THE THREE ERRORS I ROUTINELY GET WHEN TRYING TO USE THE VIRTUAL INSTRUMENTS LISTED ABOVE:

"Lost communication with audio interface. Please try increasing H/W Buffer Size or removing some plug-ins, and make sure you have a valid clock source (-6097)." NOTE: I get this error 90% of the time... There is only one plugin running, and messing with the H/W buffer has no effect.

"You are running out of CPU power. Remove some RTAS plug-ins or increase the CPU usage limit in the Playback engine dialog (-9128)." NOTE: Following these suggestions has no effect.

"The operating system held off interrupts for too long. If this occurs frequently, try increasing the H/W Buffer Size" in the Playback engine panel (-6086)." NOTE: Messing with the H/W, as above, has no effect.

MY RIG:
PowerMac with Dual 1 Ghz PowerPC G4 processor (2.1)

Mac OSX 10.5.4

Pro Tools v. 7.4.2

1.5 gig SDRAM

Two internal ATA drives

Peripherals: USB mouse, USB keyboard, FW Digi 002 interface, FW hard drive with Oxford 911 chipset, USB M-Audio Oxygen61
MIDI controller

My Digi 002 control surface's serial number does end in an "E"...

Thanks again, and please let me know if I've left any details out or if I can answer any questions.

-Chris B.