There is a bug in Renoise and EMU 0404 USB. The sound starts to stutter, and I have to reinitialize the driver when this happens. Doesn’t matter what settings I have. It happens no matter what settings I use.
This seems to be a general issue with the EMU 404. You may try the following:
When using its ASIO drivers, completely diable the drivers in Windows (Windows -> Audio Playback -> Devices). Looks like it has lots of problems when beeing used by Windows & ASIO at once.
Try to use ASIO if you use Directsound now or DirectSound if you ar eusing ASIO now. Also the ASIO4All drivers might work better that EMUs: http://www.asio4all.com/
Finally, try to look for other EMU users out there who have the same problem. Maybe their solution also works for you. Its very very unlikely that this is a Renoise problem. Theres really not much we can do wrong to support this card.
I just traded my 0404USB for an 1820M. I know exactly the problem you are having and the workaround.
It is caused by latency. The 0404USB starts to crackle under load, and the lower the latency the more likely this is to happen. Once it starts crackling if you don’t stop the song the drivers seem to “corrupt” and you need to hit control-comma to bring up the preferences and re-initialize the drivers.
If I set my latency to 14ms it seemed to work well except under the heaviest of loads. I would give that a shot. If you still have it happen you could try to increase latency, but 14 was still pretty fast, and worked well for me.
EDIT: Also, the unoffical e-mu 0404USB support forum: http://productionforums.com/viewforum.php?f=110
Thanks for the info! Will look it up.