Thanks for your reply, Joel! Joel Roth wrote: > On Sat, Feb 07, 2009 at 03:54:41PM +0100, Johannes Wiedersich wrote: >> Hallo all! >> >> On switching my usb sound card to 24bit audio, all applications using >> the card will crash/segfault: >> >> $ aplay led_zeppelin-houses_of_the_holy-a.wav >> Playing WAVE 'led_zeppelin-houses_of_the_holy-a.wav' : Signed 16 bit >> Little Endian, Rate 44100 Hz, Stereo >> Segmentation fault > > There are many wrinkles and ways of solving problems > with Linux audio. > > At the ALSA level, the 'default' pcm device as provided by modern > kernels automatically performs format conversion. Maybe some > of the others, too. > > $ aplay -L > > provides a list of your system's ALSA pcm sound devices.
$ aplay -L surround40:CARD=USB2448,DEV=0 PHASE 26 USB(24/48), USB Audio 4.0 Surround output to Front and Rear speakers surround41:CARD=USB2448,DEV=0 PHASE 26 USB(24/48), USB Audio 4.1 Surround output to Front, Rear and Subwoofer speakers surround50:CARD=USB2448,DEV=0 PHASE 26 USB(24/48), USB Audio 5.0 Surround output to Front, Center and Rear speakers surround51:CARD=USB2448,DEV=0 PHASE 26 USB(24/48), USB Audio 5.1 Surround output to Front, Center, Rear and Subwoofer speakers surround71:CARD=USB2448,DEV=0 PHASE 26 USB(24/48), USB Audio 7.1 Surround output to Front, Center, Side, Rear and Woofer speakers looks fine to me, but there is no line that looks like plain 'stereo'. If I switch to 16 bit on the sound card, sound works and shows this: $ aplay -L default:CARD=USB1648 PHASE 26 USB(16/48), USB Audio Default Audio Device front:CARD=USB1648,DEV=0 PHASE 26 USB(16/48), USB Audio Front speakers surround40:CARD=USB1648,DEV=0 PHASE 26 USB(16/48), USB Audio 4.0 Surround output to Front and Rear speakers surround41:CARD=USB1648,DEV=0 PHASE 26 USB(16/48), USB Audio 4.1 Surround output to Front, Rear and Subwoofer speakers surround50:CARD=USB1648,DEV=0 PHASE 26 USB(16/48), USB Audio 5.0 Surround output to Front, Center and Rear speakers surround51:CARD=USB1648,DEV=0 PHASE 26 USB(16/48), USB Audio 5.1 Surround output to Front, Center, Rear and Subwoofer speakers surround71:CARD=USB1648,DEV=0 PHASE 26 USB(16/48), USB Audio 7.1 Surround output to Front, Center, Side, Rear and Woofer speakers iec958:CARD=USB1648,DEV=0 PHASE 26 USB(16/48), USB Audio IEC958 (S/PDIF) Digital Audio Output null Discard all samples (playback) or generate zero samples (capture) > Now for your system, you should reboot or unplug and replug > your USB sound device after changing to 24-bit to ensure the > ALSA driver reads the 24-bit configuration. Done, redone and repeated again ;-) So far without success. It seems to be either a config problem or a bug (alsa or kernel?). > You can also choose to specify in your $HOME/.asoundrc file what the > output format to the soundcard should be for a particular > device. How to do that? http://alsa.opensrc.org/index.php/.asoundrc shows how to set the sample rate, but that seems to fine, here. > I find the Ecasound provides an easy way to handle > format conversions. > > $ ecasound -i cd-stereo.wav -f:s24_le,2,44100 -o alsa,hw:0 Playing a wav with this command line works. > Ecasound is a swiss-army knife of audio processing, > can do many common audio processing tasks. > >> kaffeine, amarok, xine etc. all just crash. > > It sounds like a configuration problem, maybe ALSA > needs to be told that your USB soundcard is set to 24 bits. How to do that? > This suggests that you are 99% there, since your ALSA driver is > already taking care of converting the signal from 44100 to > 48000 Hz. > > Good luck with that last 1%. 24 bits will help if you > are doing multitrack stuff. In which case you might > consider Audacity (friendly GUI), Ardour (total pro) > or even Nama (http://ecmd.infogami.com) which I have > developed using Ecasound for audio processing. Audacity doesn't crash :-) , however, my speakers start to beep and crack in all unpleasant sounds imaginable, as soon as I start it (without trying to play or record anything). I should have told before, that the sound card works fine on 24 bit on etch, but NOT on lenny. I just checked with the etch system of my girl friend. There it works 'plug and play' without a glitch and without having to configure anything. Thanks, Johannes
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