On Oct 30, 2012 12:44 AM, "Lewis Pike" <phaselocker@gmail.com> wrote:
> I've too have an M-Audio Fast Track Pro and I've found that it's audio
> capture works unreliably under Linux.  I only tested it using arecord
> and I have not tried Jack.
> I find that on random takes the audio will become heavily distorted.
> Usually this sounds as though additional gain is being introduced and
> there is what sounds like very audible quantization distortion.  Once
> the problem appears, it persists until the device is reset.

Thanks for this... so, 46 ms latency in my concert and count myself lucky it isn't worse. And, replace the ftpro when I can...

> If you are able to successfully configure this device for recording in
> any capacity you are doing better than me.

My experience using it with Jack is: if audio input is correct when Jack starts, then it stays OK as long as the Jack server is running. I have also seen the problem with default Jack settings, but rarely, certainly less often than you report. The difference is that I start Jack and keep it running for a whole session, maybe several hours, while in your case, arecord connects to the hardware fresh on every take, raising the probability of a failed take.

I'm fairly certain if you use Jack and keep one connection to the Fast Track alive for a longer time, the issue will not go away totally, but it's manageable. Check for good input at the start of the session, and then you should be OK.