On Tue, 2010-07-06 at 10:57 +0100, Daniel James wrote: [snip] > I notice > http://www.rme-audio.de/en_support_techinfo.php?page=content/support/en_support_techinfo_steadyclock > doesn't mention USB or MIDI at all. > > Cheers! > > Daniel
Hi all :) hi Daniel :) I'll read this link tomorrow, I just did a short test, right after the postman did give me the ordered equipment. Please take a look at all the tests I did here. The Terratec's MIDI might be ok, but ... spinymouse1...@suse11-2:~> cat .alias alias cpu-o="su -c\"cpufreq-set -gondemand\"" alias cpu-p="su -c\"cpufreq-set -gperformance\"" spinymouse1...@suse11-2:~> cpu-p Password: spinymouse1...@suse11-2:~> uname -a Linux suse11-2 2.6.31.6-rt19 #1 SMP PREEMPT RT Wed Nov 18 16:59:26 CET 2009 x86_64 x86_64 x86_64 GNU/Linux spinymouse1...@suse11-2:~> alsa-midi-latency-test -l Port Client name Port name 14:0 Midi Through Midi Through Port-0 16:0 TerraTec EWX24/96 TerraTec EWX24/96 MIDI 20:0 USB Device 0x170b:0x11 USB Device 0x170b:0x11 MIDI 1 spinymouse1...@suse11-2:~> alsa-midi-latency-test -i16:0 -o16:0 > SUCCESS best latency was 0.98 ms worst latency was 1.42 ms, which is great. spinymouse1...@suse11-2:~> alsa-midi-latency-test -Rrw20 -i16:0 -o16:0 > SUCCESS best latency was 0.99 ms worst latency was 1.11 ms, which is great. Then I run glxgears and Firefox with windows always on top and moved the Firefox window while running the tests. spinymouse1...@suse11-2:~> alsa-midi-latency-test -i16:0 -o16:0 > SUCCESS best latency was 0.98 ms worst latency was 4.15 ms, which is great. spinymouse1...@suse11-2:~> alsa-midi-latency-test -Rrw20 -i16:0 -o16:0 > SUCCESS best latency was 0.99 ms worst latency was 1.11 ms, which is great. Then I tested if the hrtimer might change something, I dunno if the test will use it automatically. spinymouse1...@suse11-2:~> su Password: suse11-2:/home/spinymouse11.2 # chgrp audio /dev/hpet suse11-2:/home/spinymouse11.2 # sysctl -w dev.hpet.max-user-freq=64 dev.hpet.max-user-freq = 64 suse11-2:/home/spinymouse11.2 # modprobe snd-hrtimer suse11-2:/home/spinymouse11.2 # cat /proc/sys/dev/hpet/max-user-freq 64 suse11-2:/home/spinymouse11.2 # exit Firefox and glxgears still on top of the windows and I moved the Firefox windows again during the test. Note that I now used the -R switch for both tests. pinymouse1...@suse11-2:~> alsa-midi-latency-test -Ri16:0 -o16:0 > SUCCESS best latency was 0.99 ms worst latency was 1.08 ms, which is great. spinymouse1...@suse11-2:~> alsa-midi-latency-test -Rrw20 -i16:0 -o16:0 > SUCCESS best latency was 0.99 ms worst latency was 1.12 ms, which is great. Just for comparison one test for the Swissonic USB MIDI device, without running glxgears or Firefox or moving any window. HPET still enabled. spinymouse1...@suse11-2:~> alsa-midi-latency-test -Rrw20 -i20:0 -o20:0 > SUCCESS best latency was 1.17 ms worst latency was 2.23 ms, which is great. Now a final comment to those tests. When I used the USB MIDI device + HPET the audible result wasn't usable for music, but I had the impression that half of the jitter would solve this issue. If the results of the test are correct and if nothing would change when running JACK and doing hard disk recording too, then I guess the PCI MIDI could be ok. I don't have much time today, perhaps tonight or tomorrow I'll mount the new HDD and restore my 64 Studio's. When it's done I'll record some music and additionally I'll ask Achim, http://achimjaroschek.com/ , to stress the computer by playing the Roland drums and some hardcore Classic or hardcore Jazz on the keyboards. It's not only that he plays with all those music giants like Jasper van't Hof, Peter Brötzmann etc., but he once throw his Apple through the window and he always advise me not to make music using the computer anymore. I've got a good feeling, that around 1ms (when the -R switch is set) would be good enough to make music, but again, even if the test says 2.23 ms for the USB device should be great, the USB device is unusable for serious musicians, it results in music that might be done by am idiot without any sense for music. I couldn't use the USB device + HPET even for the simple Pop-Rock I sometimes make. Cheers! Ralf _______________________________________________ 64studio-devel mailing list 64studio-devel@lists.64studio.com http://lists.64studio.com/mailman/listinfo/64studio-devel
