Hello,

I've been using my RME Fireface UC with a Mac Pro Quad 2.66 (2009) and Logic Pro without issues for a while. I'm working in 44.1 KHz most of the time, converting upwards to 48 KHz for film/TV projects. The conversion happens when bouncing (i.e. I change the settings in the resulting AIFF file and the file is up-sampled after Logic finished writing it) — I never change the sample rate inside Logic. I know it may sound weird but (1) I've yet to find someone who notices any difference and (2) it's not the point of this post

The Fireface UC is also selected as the output device in the "System Preference - Sound" pane. Through the "USB Settings" applet it's set to 44.1 and I presume this is what's played through the system output.

Now, playing stuff through Logic is fine. However, whenever I use the Finder quicklook to have, well, a quick look at my 48 KHz bounces, I often get clicks in the audio which are totally random (both in time and intensity). Not many, 4 or 5 in a 2-minute piece, but enough to be noticed. These are not clicks caused by digital clipping in Logic (there is none), and the TotalMix meters never go into the red.

I've been accepting this for months because I was saying to myself it was one of those things nobody could ever figure out, but now I'm wondering if I'm wrong assuming this

Thanks for your help.

BTW: SL 10.6.6, FFUC FW v112, Driver v1.49.