I'm wondering if anyone's experiencing similar problems with MOTU Firewire interfaces under Mavericks. There are few other people talking about this on Apple's discussion board so I don't think I'm the only one..
So in my case, the problem is this:
My setup: Mac mini mid-2011, quad 2GHz i7, 16G RAM, OS 10.9.3, DP 8.06 (64bit), Original MOTU 8Pre connected via Firewire.
1) Any MOTU Audio System later than 57985 (June 2013) completely messes up audio, system wide.
What I get, when I install newer drivers, in my case, is that, I get a nasty high-mid digital ring only from my left speaker, and on my right speaker, I get something resembling the audio I expect to hear, but as if it's played back from an old radio. This is system wide, not only DP, e.g. 'empty trash' sound comes out this way too.
2) When I reverted to the above mentioned 57985 driver, it works most of the time. But I still get occasional glitch on playback and record. When it happens during recording, it gets recorded. Thankfully it hasn't happened while recording on DP yet, but this sort of uncertainty is not ideal... The glitch is system wide too, when I'm listening to something just using QT player, or on a website, the sound glitches occasionally.
3) One participant on Apple's board seemed to be getting a better result by using an even older driver (55333 from Sept. 2012). So at the moment, I've installed this driver and seeing if it solves the issue.
This problem doesn't seem to be a very widespread one, but I think there are more than a few people experiencing this, so please chip in if you've had similar issues, and better still, how you solved it!

Thanks, Taka