On Thursday 07 May 2009 15:43, Clemens Ladisch wrote: > Niels wrote: >> - This is with Kubuntu 9.04. For some reason it ships with ALSA >> 1.0.18rc3. Is it worth upgrading, > > Probably not, AFAIK there haven't have any relevant changes. > >> and how would I do that, other that wait for an automatic update? > > Download, compile and install the 1.0.20 alsa-driver package. > I did that, no problems. >> - speaker-test says it outputs to "Front left", but it actually outputs >> to both left and right. > > Doesn't it ever output to "front right"? This looks like a mono mode. > > What device name and number of channels did you tell speaker-test to use? > I disabled the internal sound card, so that the usb-audio is now the only sound card: $aplay -l **** List of PLAYBACK Hardware Devices **** card 1: default [USB Audio DAC ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 But now speaker-test fails: $ speaker-test speaker-test 1.0.20 Playback device is default Stream parameters are 48000Hz, S16_LE, 1 channels Using 16 octaves of pink noise ALSA lib confmisc.c:768:(parse_card) cannot find card '0' ALSA lib conf.c:3513:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings ALSA lib conf.c:3513:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory ALSA lib confmisc.c:1251:(snd_func_refer) error evaluating name ALSA lib conf.c:3513:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory ALSA lib conf.c:3985:(snd_config_expand) Evaluate error: No such file or directory ALSA lib pcm.c:2211:(snd_pcm_open_noupdate) Unknown PCM default Playback open error: -2,No such file or directory There seems to be a problem with card0 vs. card1. >> - How do I disable dmix and other possible sources of signal degradation >> completely? > > Dmix does not degrade the signal because its design requires it to run > with a sample rate and a sample format directly supported by the device. > Ah, that's good then. > You can disable dmix by telling your application(s) to use another > device name instead of "default". > >> - How do I make sure ALSA doesn't resample or normalize the signal along >> the way? > > Use a device name like "dmix" or "hw". > "default" and "plughw" include resampling, if needed. > > In no case is there any normalization. > Judging from /usr/share/alsa/cards/USB-Audio.conf I have a number of devices available, such as USB-Audio.pcm.front.0 USB-Audio.pcm.default USB-Audio.pcm.default_playback_dmix_yes USB-Audio.pcm.default_playback_dmix_no however they don't all show up in "aplay -L". There's no way to select a specific device in KDE's sound system, so I'd have to configure ALSA to use a certain device as default. How would I do that? >> - How do I test various sample rates and bit depths? > > Play a file with the desired properties to the "hw" device. > Clever, I'll try that! >> How do I get ALSA to tell me what the device supports? > > Have a look into /proc/asound/card???/stream0. > Apparently it only supports 16 bit, 32000, 44100, 48000 Hz. The card does "24 bit 192kHz upsampling", so I'd hoped to have something like that available for playing samples. Ho-hum, I guess not. Thanks! Niels ------------------------------------------------------------------------------ The NEW KODAK i700 Series Scanners deliver under ANY circumstances! Your production scanning environment may not be a perfect world - but thanks to Kodak, there's a perfect scanner to get the job done! With the NEW KODAK i700 Series Scanner you'll get full speed at 300 dpi even with all image processing features enabled. http://p.sf.net/sfu/kodak-com _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
