On 04/03/2014 11:16 AM, Daniel Mack wrote: >> TEAC TEAC USB AUDIO DEVICE at usb-0000:00:1d.0-1.4, high speed : USB Audio > > That's a device with IDs 0644:8038, correct?
That's right, here's how the USB stack announces it: [67129.718571] hid-generic 0003:0644:8038.0006: input,hidraw2: USB HID v1.00 Device [TEAC TEAC USB AUDIO DEVICE] on usb-0000:00:1d.0-1.4/input0 > Interface 3 refers to ... > >> Altset = 2 >> Packet Size = 156 >> Momentary freq = 183992 Hz (0x16.ffc0) >> Feedback Format = 16.16 >> Interface 3 >> Altset 1 >> Format: S16_LE > > ... 16bit, so things don't work for you in 192k/16bit, right? Well, it's not like I had experienced a lot with it, but the few times I tried 16/192, I didn't hear the crackles that are very noticeable in 24/192. More on this below > Just for the sake of comparison, could you try playing the following > file with aplay? > > http://zonque.org/sine-192khz.wav (~22 MB) > > I get stable sound output with > > aplay -Dhw:xxx --buffer-size=256 Music/sine-192khz.wav I just tried to playback this file with your buffer size and I can confirm there are issues in 16/192 too: with buffer-size=256, lots of crackle s. Buffer needs to be raised to 384/512 to sound normal. Yesterday I got my hands on more diverse 24/192 content to make more experiments. I've come to the conclusion that the crackles that were very noticeable with the patch mentioned upper in the thread are not 100% absent without the patch, they are just very less frequent and harder to notice, but are still there. The experiments I made yesterday were using aplay, without specifying any buffer size, here's what aplay -vD[..] gives playing some of this new content without specifying the buffer size: Its setup is: stream : PLAYBACK access : RW_INTERLEAVED format : S24_3LE subformat : STD channels : 2 rate : 192000 exact rate : 192000 (192000/1) msbits : 24 buffer_size : 96000 period_size : 24000 period_time : 125000 tstamp_mode : NONE period_step : 1 avail_min : 24000 period_event : 0 start_threshold : 96000 stop_threshold : 96000 silence_threshold: 0 silence_size : 0 boundary : 6755399441055744000 appl_ptr : 0 hw_ptr : 0 Seems to default to a much bigger buffer size. What's interesting that if a smaller buffer (e.g: 512) is specified I'm really unable to spot any crackle. Could it be a question of sweet spot that some apps have a hard time finding? -- Julien Benoist ------------------------------------------------------------------------------ _______________________________________________ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
