Thanks for replying Steve. I felt helpless before!
First I will give you as much information as possible:
I have a Triton Extreme keyboard, with its 16 channel sequencer being played by Cubase SX3 version 3.1.0. My interface is an M-Audio Fast Track Pro. My PC was built in 2006 by Digital Village to be a dedicated music PC. It has dual Pentium 3.2GHz processors and 2Gb of RAM. It runs Windows XP 32-bit, service pack 3.
MIDI Connection paths are: Triton>5-pin MIDI> M-Audio>USB>computer>USB>M-Audio>5-pin MIDI>Triton>Audio L &R>Speakers.
The jittering in live MIDI input occurs regardless of whether the input is on the same or different channel to those being played back at the same time. It also occurs regardless of whether there are Audio tracks being played back. The problem is not present if the other MIDI tracks are muted. Also, the problem comes and goes. After a while it works okay, then minutes later, OR sometimes when I close and reopen Cubase, it comes back.
I tried starting a new project with only MIDI tracks, no audio. The problem occurred when I reached about 5 tracks but I suspect that this is a coincidence due to the fact that the problem comes and goes every so often.
I use Direct music, not Windows MIDI and have ‘use system timestamp’ ticked.
I have M-Audio ASIO driver selected and released in background. I tried ticking and unticking the boxes: ‘Multiprocessing’ and ‘Adjust for record latency’.
I went into File/Preferences/MIDI and changed MIDI max feedback from 250ms to 50ms and back.
I changed the M-Audio settings from 24-bit to 16-bit and back. Sample rate is 44.1kHz.
I read in a SoundOnSound article about a problem called ‘live MIDI buffering jitter’, caused by the sequencer quantising MIDI being played in to the nearest audio buffer, resulting in a random jitter being heard on the live track being recorded even though it is being recorded as played in. This is exactly what I’m experiencing.
However the size of inaccuracy in the jitter is more like 100ms. Surely my 25ms of audio latency would only cause a maximum offset of jitter of this amount. Nevertheless I did what the article suggested and reduced my audio buffer size (in my case from 1024 to 256 samples), giving a reduced latency of 8ms. The jitter was no different.
The only thing I wasn’t sure about was what you meant by ‘experimenting with analogue audio’.
I just want to create music and haven’t been able to properly since I got the M-Audio 2 years ago. I did have a Motu 828 MkII which worked without jitter but then it blew a capacitor and I got the M-Audio for less than the repair would have cost.
Is there anything else I could try? I can’t help feeling like if you were here you would look at my setup and pick up on something obvious and say ‘you just need to change this setting or routing’ - and it would work all of a sudden!
Don’t give up on me!
Michael