setting up multichannel output with alsa

[curmudgeon]

Yes, I have read https://wiki.gentoo.org/wiki/ALSA

Everything works perfectly with two channel stereo (except that every time I plug in or remove a flash drive, KDE is always telling me that certain devices are either unavailable or available again).

Aplay shows plenty of devices (with lots of channels): :)

Code: Select all

$ aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=MID
    HDA Intel MID, ALC889 Analog
    Default Audio Device
sysdefault:CARD=MID
    HDA Intel MID, ALC889 Analog
    Default Audio Device
front:CARD=MID,DEV=0
    HDA Intel MID, ALC889 Analog
    Front speakers
surround21:CARD=MID,DEV=0
    HDA Intel MID, ALC889 Analog
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=MID,DEV=0
    HDA Intel MID, ALC889 Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=MID,DEV=0
    HDA Intel MID, ALC889 Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=MID,DEV=0
    HDA Intel MID, ALC889 Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=MID,DEV=0
    HDA Intel MID, ALC889 Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=MID,DEV=0
    HDA Intel MID, ALC889 Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=MID,DEV=0
    HDA Intel MID, ALC889 Digital
    IEC958 (S/PDIF) Digital Audio Output

But it won't test:

Code: Select all

$ /usr/bin/speaker-test -c 6 -t wav

speaker-test 1.0.28

Playback device is default
Stream parameters are 48000Hz, S16_LE, 6 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 2048 to 16384
Period size range from 1024 to 1024
Using max buffer size 16384
Periods = 4
was set period_size = 1024
was set buffer_size = 16384
 0 - Front Left
 1 - Front Right
 2 - Unused
 3 - Unused
 4 - Unused
 5 - Unused
Time per period = 8.298641

$ /usr/bin/speaker-test -c 6 -D surround51 -t wav

speaker-test 1.0.28

Playback device is surround51
Stream parameters are 48000Hz, S16_LE, 6 channels
WAV file(s)
Playback open error: -16,Device or resource busy

What am I doing wrong?

[rkfsm]

I had a similar problem. Take a look at this thread and see if it helps.

RK

[curmudgeon]

I had a similar problem. Take a look at this thread and see if it helps.

Unfortunately, it didn't (I am not using pulseaudio), but thanks.

[mimosinnet]

But it won't test:

Code: Select all

$ /usr/bin/speaker-test -c 6 -t wav

speaker-test 1.0.28

Playback device is default
Stream parameters are 48000Hz, S16_LE, 6 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 2048 to 16384
Period size range from 1024 to 1024
Using max buffer size 16384
Periods = 4
was set period_size = 1024
was set buffer_size = 16384
 0 - Front Left
 1 - Front Right
 2 - Unused
 3 - Unused
 4 - Unused
 5 - Unused
Time per period = 8.298641

What am I doing wrong?

Do you hear any sound? speaker-test -c 6 -t wav gives me the same result than you. With 4 speakers (front/rear), this works for me:

Code: Select all

speaker-test -D plug:surround40 -twav -c 4 

speaker-test 1.0.28

Playback device is plug:surround40
Stream parameters are 48000Hz, S16_LE, 4 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 32 to 8192
Period size range from 16 to 4096
Using max buffer size 8192
Periods = 4
was set period_size = 2048
was set buffer_size = 8192
 0 - Front Left
 1 - Front Right
 3 - Rear Right
 2 - Rear Left
Time per period = 5,718027

Cheers!

[curmudgeon]

Do you hear any sound? speaker-test -c 6 -t wav gives me the same result than you. With 4 speakers (front/rear), this works for me:

Code: Select all

speaker-test -D plug:surround40 -twav -c 4 

speaker-test 1.0.28

Playback device is plug:surround40
Stream parameters are 48000Hz, S16_LE, 4 channels
WAV file(s)
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 32 to 8192
Period size range from 16 to 4096
Using max buffer size 8192
Periods = 4
was set period_size = 2048
was set buffer_size = 8192
 0 - Front Left
 1 - Front Right
 3 - Rear Right
 2 - Rear Left
Time per period = 5,718027

I get absolutely nothing for anything more than two channels (either output or test). No sound, and either "unused" (if I just specify the number of channels) or "Device or resource busy" (if I try to specify a device).

[mimosinnet]

or "Device or resource busy" (if I try to specify a device).

Do you mean that you get the message "Device or resource busy" with this command:

Code: Select all

aplay -D surround40 test.wav

There may be another program using the card. For example, this command:

Code: Select all

$ aplay -D surround40 test.wav & aplay -D surround40 test.wav
[1] 7354
Playing WAVE 'test.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
aplay: main:722: audio open error: El dispositiu o recurs es troba ocupat

gives me this same error. Could that be something related with KDE? Do you get the same error if you issue the command before starting KDE?

Cheers