[pulseaudio-discuss] module-remap-sink not working for surround card

Martin Klein martin.klein.de at gmail.com
Sun Jan 18 04:54:42 PST 2015

2015-01-14 21:16 GMT+01:00 Tanu Kaskinen <tanu.kaskinen at linux.intel.com>:
> On Mon, 2015-01-12 at 14:42 +0100, Martin Klein wrote:
>> 2015-01-09 12:59 GMT+01:00 Tanu Kaskinen <tanu.kaskinen at linux.intel.com>:
>> > It sounds like the surround51 alsa device isn't working as it should.
>> > What if you try "speaker-test -D surround51:0 -c 6 -t wav"? Does it work
>> > as expected?
>> >
>> This is working as expected (i.e. the from the rear output I hear
>> "rear left, rear right" and from my front output I hear "front").
>> However, changing the volumes of rear in pavucontrol still doesn't
>> change anyting. Changing the volume of front effects all output
>> channels. In alsamixer, changing the volume of rear and front works as
>> expected.
> I suggest that you don't think too much about the volume controls at
> this point, because volume control can contain extra complications.
> If speaker-test -D surround51:0 works, then it indeed appears to be a
> problem in pulseaudio. What if you don't load the remap sinks, and just
> try to play noise to the different channels of the alsa sink like this:
>     pacat --volume=1000 --no-remix --channels=1 --channel-map=front-left /dev/urandom
> (I set the volume to a relatively low value, because the noise can be
> pretty loud.)
> Try that command with different channel maps. Always specify just one
> channel of the 5.1 setup. There should be noise from only one channel,
> and if the specified channel is e.g. "rear-right", you of course should
> hear the noise from the rear right speaker. Does it work?
Okay, this works as expected, i.e. I hear the noise on the intended
speaker. Thank you for suggesting this test. Now to summarize: In
principle surround seems to work with both Alsa and Pulse (i.e. I can
output sound on only the intended speaker). However, both volume
controls and module-remap-sink does not work for the surround channels
with pulseaudio. Any ideas on how to debug this further?

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