Message to self: it seems that one has to wait for updated RPi USB firmware/drivers to get USB 2.0 audio going. Obviously the "isochronous transfer mode" as used by audio interfaces is currently broken. gr~~~
2013/1/26 Thomas Grill gr@grrrr.org
Hi all, for my USB audio class 2.0 device "Native Instruments Komplete Audio 6" i can't report such good news. There is constant irregular crackling, not only with Pd but also with aplay etc. It seems related to USB bandwidth, since turning on and off the inputs in Pd changes crackling frequency. The dwc_otg.speed setting is not usable for me, since the device is dependent on USB 2.0 operation. Any experiences with USB 2.0 audio devices under ALSA/rpi? thanks, gr~~~
2013/1/26 Cyrille Henry ch@chnry.net
hello,
I just install raspbian release and update it. then install pd 0.44.1 (without any specific optimisation flag)
I made the standard optimisation :
- rtprio 99
- memlock 1000000000
in /etc/security/limits.conf
and dwc_otg.speed=1 in /boot/cmdline.txt as suggested by miller
I use a uca222 beringher (that cost about 20 or 25€) sound card. trying the test audio and midi, there is no click with 10ms audio buffer (with adc~ enable).
this is with usb keyboard / mouse combo plugged and graphical interface (for the system and for pd).
without X, audiobuf can be as low as 5ms
having a usb keyboard did not change anything for me.
i'm very happy
cheers c
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