hi,
After some testing with the advices of Timur, things seems to going better on bootcamp/xp:
With a 128 buffer, i have now only rare small clicks/pops with or without errors (counter 0/4) after 20 minutes test.
Not perfect but better than snow l?o (the error counter is very useful on windows drivers).
I think to open a new post for separate the sleep/hot-plug distortion problem and the distortion/dropout/clicks/pops problem.

Yes, using an USB hub or switch has no impact on the problem for me neither (first I suspected the hub to be the culprit).

When I experienced the distortion problem it always also affected the NI Kore 1 when I checked while other non-audio USB interfaces where not affected. My suspicion is that only the isochronous mode of OS X USB driver gets shot down, no idea by what though.

I haven't been using OS X for some weeks now and the new laptop came with Snow Leopard. I'm not impressed by the build quality of the new unit, but Apple exchange support does not answer at the moment.

hi GrooveNinja,
I presume you have the last firmware and driver (fw 91 and driver 1.19) ?

And like said Blindflug: Happy Christmas to everybody

Hello All,

I have definitely the same problems (very distorted, sounds like bit-crush, sound-playing) with fireface UC. The salesman at the music shop i bought my fireface UC told me, there could be some problems with MacBook pro (late 2008) with fireface firewire so i decided to buy the UC version.
Reproducible after some times working with mac and stay not connected to USB fireface interface without rebooting and maybe some systems sleeps i always have to reboot my macbook to get undistorted audio signals. For me this looks like a problem with the very tuned USB driver(?).
Clean Reboot always fixes the issue (but i really don't like this way)

My Setup is:
MacBook pro 15'' (late 2008 - UniCase with removable Battery) - MacOs 10.6.2, 2.8 GHz Core 2 Duo, 4GB RAM
Cubase 5.1 (but all other applications like VLC or quicktime have the same behavior, so it's not a problem of Cubase)
Fireface UC with latest drivers/firmware

Is there an upcoming driver fix for this issue?

If i can help with tests, don't hesitate to ask -I am very familiar with programming and testing IT-related equipment.
There is another problem with DigiCheck, but this is off-topic for this...

So far ,
Greets inetics

Does anyone experiencing the problem *not* have an unibody (NVidia 730i/9400 based) Mac?

Also have a look at this thread of mine: http://www.rme-audio.de/forum/viewtopic.php?id=7308

Maybe you can try some of the things I did there (big buffer size, sleep).

Actually I think the issue I reported about in the other thread might very well be connected to this one here. At least the symptoms seemed quite similar in the end except for that the Kore kept working.

It seems we have all here 4 GB memory.

Hello,
For some unknown reason, RME team is mute for us, well what can we do now ? i don't know

So I've tested the USB-plugin-card - the problem still persists. Also tried all different sample frequencies, but no change.
Once the Macbook gone to sleep - heavy distortion occures on FFUC audio outputs. That causes me to reboot to work with and everything is fine. It is a bit opposite of "mobile" working as long as the sleeping function is one of  the main mobile features using a MBP without rebooting for a long time (usually i am rebooting less than once a week).

So I'am sorry telling you no good news..

Cheers

As far as we can read out of these statements something happens that is not supposed to happen: the USB audio transfer is seriously broken and needs to be reset.

As you can read on our general information USB audio is supposed to (and indeed does) work exemplary in Core Audio. On our machines we were not able to break the stream so that wrong (misaligned) data is transmitted. The special error detection and correction that we implemented in driver and hardware works under Windows only at this time, as it was not needed for the Mac.

Seeing that now some people start to have problems like that we will implement the same technique into the Mac side too. Soon.

BUT: you have to be aware that this might not finally fix it. A drop out that is so big that it screws the transmission will still be there with error correction, the only difference that after the drop out (mute or click) the sound continues.

IMHO that is not the real deal, as you can never be sure about the integrity of your audio data. The ideal solution therefore is to change to a hardware that doesn't show the problem in the first place.

Problem with this issue is that it does not happen as reproducable on anyone's Macs as it does on yours. I had this issue ever since I used the UC, but I was not able to pin down what caused it. I *did* suspect some sleep mode connection, but it only happens once in a while here.

And when it happens it often affects the whole USB isochronous audio stream, which means even my NI Kore USB interface is affected (last time I had a case where it was not though). All a bit complicated...

Hi Titirom,

also thank you for your reply,

yes i am on Snow Leo (migrated from Leo, but bought UC after migration) and had never installed old drivers - so most of the listed files/direcories were not there.
After a cold start and putting computer to sleep and woke it up - it now worked well. After a day of work without any parallels etc. and after that plugging in UC i had same distortion as explained before even with 176khz (what i tried before too). So nothing really news at the moment..
Another thing could be very often i am using VM-software like VM-Ware, Parallels and VirtualBox - may that cause some problems as at least parallels tries to grab control over newly plugged USB devices and may disturb USB communication until next reboot..
Anyway - thank you for your support!

Cheers

Hi All,
I've come to a new conclusion. Maybe mine is faulty.. as it's now displaying the same problem on every Mac I've used it with. From a new iMac, to a new Mac pro... The distortion problem is happening way too often. I'm booking it in for a repair. This just isn't right. I've read all the posts, but I can't keep trying new things to make this piece of gear work. It's been over 6 months and I've never really been able to use it seriously. If it's not fixed I will be seeking my money back. Meanwhile, my second hand Fireface 400 (that I had to purchase) is flawless.

Yes I have. It appeared to be fine on a pc. But I didn't test it for any longer than about 20 mins. It's only displaying this problem on Macs. Multiple. And that's what I need it for and use.

It was purchased in Melbourne. I recieved a call from tech support here today but unfortunately I couldn't take it as I  was in a sesssion. I will take it up with them next week.

As I said, 6 months of problem solving with tech support help from your australian reps and still no luck. I don't want to test it anymore, I just want something that works.