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ALSA: snd-usb: New streaming logic causes distortions on Burr-Brown DAC

Bisected Markus Trippelsdorf 3 participants 4 messages Jun 8, 2012 – Jun 9, 2012

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Markus Trippelsdorf

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I hear distortions on my Burr-Brown USB DAC whenever the (software) volume is set to some value lower than 100% in mpd. The lower the volume the bigger are the resulting distortions.

I've bisected this to the two commits below:
(One wouldn't compile without the other)

commit d399ff9593e088d33fb38f5206c6427825892baa

Author: Daniel Mack <[email protected]>
Date:   Thu Apr 12 13:51:13 2012 +0200

ALSA: snd-usb: remove old streaming logic

commit edcd3633e72a1590c4cf46befe5e6cd03b5aec3e

Author: Daniel Mack <[email protected]>
Date:   Thu Apr 12 13:51:12 2012 +0200

ALSA: snd-usb: switch over to new endpoint streaming logic

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Markus
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Quoted 3 lines · Markus Trippelsdorf

I hear distortions on my Burr-Brown USB DAC whenever the (software) volume is set to some value lower than 100% in mpd. The lower the volume the bigger are the resulting distortions.

see patch: http://marc.info/?l=linux-kernel&m=133905533312625&w=2

You're probably getting distortion because mpd decided it would use a stream format that's only 8bit.

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Jamie Heilman                     http://audible.transient.net/~jamie/
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#2 lore raw
Quoted 9 lines · Jamie Heilman
Quoted 3 lines · Markus Trippelsdorf

I hear distortions on my Burr-Brown USB DAC whenever the (software) volume is set to some value lower than 100% in mpd. The lower the volume the bigger are the resulting distortions.

see patch: http://marc.info/?l=linux-kernel&m=133905533312625&w=2

You're probably getting distortion because mpd decided it would use a stream format that's only 8bit.

Yes. The patch fixes the issue. Many thanks.

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Markus
#3 lore raw

At Fri, 8 Jun 2012 20:11:54 +0200,

Quoted 7 lines · Markus Trippelsdorf
Quoted 5 lines · Jamie Heilman
Quoted 3 lines · Markus Trippelsdorf

I hear distortions on my Burr-Brown USB DAC whenever the (software) volume is set to some value lower than 100% in mpd. The lower the volume the bigger are the resulting distortions.

Quoted 6 lines
Quoted 4 lines

see patch: http://marc.info/?l=linux-kernel&m=133905533312625&w=2

You're probably getting distortion because mpd decided it would use a stream format that's only 8bit.

Yes. The patch fixes the issue. Many thanks.

The patch is already in sound git tree, but missed in rc2. It should be in rc3.

thanks,

Takashi