Hello Mark,
I'd suggest sticking to just using St. Anne's for now, for testing:
- Try the ASIO4All driver with you audio interface.
- Try the ASIO4All driver with the PC's built-in audio output, if any.
- Try a different audio interface, if you have one to hand.
- Try not running the Hauptwerk process at real-time priority, in case it's interfering with a driver, for example.
- Make sure the MOTU firmware is up to date.
- Try reverting to the older MOTU driver.
There shouldn't be any risk in installing ASIO4All -- it shouldn't affect any other driver. After installing and configuring it, you can safely switch back and forth between it and the native MOTU driver (or any other driver) via the "
General settings | Audio device ..." screen in Hauptwerk. Doing so won't lose any settings on any other screens.
Either way, on that screen also make sure that "
Number of buffers" = 1.
mnailor wrote:Is it possible for buffer deadlines to be missed but the CPU meter doesn't show more than 2 - 3 green bars? I guess it only estimates the time available periodically so missed buffers can sneak by.
It's technically possible that a spike could be missed if it was extremely short, but even then it's very unlikely. If buffer under-runs were occurring regularly (as yours are) then the chance of none of them being visible as spikes on Hauptwerk's CPU meter is essentially zero.
Given that Hauptwerk audio recordings don't exhibit the problems, and Hauptwerk's CPU meter is consistently shwoing only green, I think the problem must be occurring after the audio has been successfully streamed from Hauptwerk to the driver, I.e. the problem is probably occurring within the audio interface, or its driver, or beyond that (cables, amplifiers, speakers). However, given that you mentioned that restarting audio/MIDI (which restarts the audio driver) resolves it for a while, it's probably within the driver or audio interface, rather than the audio cabling, amplifiers, or speakers.
Best regards, Martin.
Hauptwerk software designer/developer, Milan Digital Audio.