Am 19.11.2012 um 09:45 schrieb Peter P. p8rpp@aol.com:
- Max abonnements@revolwear.com [2012-11-19 09:05]:
I just got a RME Fireface UCX and will test it on linux soon. it has a USB class compliant mode, so it should run. The documentation says that the latency in the class compliant mode is not as good as with the proprietary driver. It would be interesting to have numbers here how much better exactly the rme driver is over the class compliant. I guess i'd simply connect output to input and measure the delay? Someone must have done this before, Is there a standard method? A patch?
Use jdelay by Fons Adriaensen. http://kokkinizita.linuxaudio.org/linuxaudio/
There is also a patch: /usr/local/lib/pd/doc/7.stuff/tools/latency.pd
Had no chance to test the Fireface UCX on linux yet, but here the results for OS X 10.8.2:
Tested with Pure Data 0.43.4-extended-20121101 /doc/7.stuff/tools/latency.pd Sampling rate 44100 Hz, delay 20 ms Blocksize 64, No callbacks
latency via USB, RME Driver print: 0.00193273 print: 0 print: 0 print: 0.000630273 print: 0 print: 0.000632601 print: 0.00253273 print: 0.000634696 print: 0.00190642 print: 0.000636792 print: 0.00191317 print: 0 print: 0.00191946 print: 0 print: 0.00192621 print: 0 print: 0.00193273 print: 0 print: 0 print: 0.000630273
latency via USB, Class Compliant Mode print: 24.3173 print: 24.3199 print: 24.3224 print: 24.3249 print: 24.3275 print: 24.33 print: 24.3326 print: 24.3352 print: 24.3377 print: 24.3403 print: 24.3429 print: 24.3454 print: 24.348 print: 24.3098 print: 24.3123
In the USB Class Compliant mode, when I change the delay in the Pd Audio properties to 40, the patch will output around 44.3. When set to 80 it will be 84.3 and so forth. Using the RME driver the latency shown in the patch always stays in the number range as seen above, no matter what delay is set in the Pd's Audio Properties. What's the explanation for this?
I have to send the Fireface back because the Firewire port is not working for me.