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You have to specify the card number otherwise amixer defaults to card 0.
Below is an example of amixer output for cards 0 and 1 on a bare Pi 4. If a USB device were plugged in and powered up it would be assigned ALSA card 2. so the command would be amixer -c2.
Code: pi@rp1:~ $ amixer -c0
Simple mixer control 'HDMI',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback -4543 [54%] [-45.43dB] [on]
pi@rp1:~ $ amixer -c1
Simple mixer control 'Headphone',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback -4543 [54%] [-45.43dB] [on]
pi@rp1:~ $
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@ Tim Curtis @ DRONE7
I am currently playing music and I can hear
my log shows this
Code: 20211022 103545 worker: ALSA cards: (0:b1 | 1:Headphones | 2:Audio | 3:empty
20211022 103545 worker: MPD config: (2:NAD USB Audio | mixer:(PCM) | card:2)
20211022 103545 worker: ALSA mixer actual (PCM)
20211022 103545 worker: ALSA PCM volume set to (amixer: Unable to find simple control 'PCM',0)
and my amixer outputs are
Code: pi@moode:~ $ amixer -c0
Simple mixer control 'HDMI',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback 0 [96%] [0.00dB] [on]
pi@moode:~ $ amixer -c1
Simple mixer control 'Headphone',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback 400 [100%] [4.00dB] [on]
pi@moode:~ $ amixer -c2
pi@moode:~ $
Does it look normal ?
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The fact that amixer does not report anything for USB device at card 2 is not normal. There should be information about the USB audio device in its output.
Another command that can be used to probe audio device capabilities is below.
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(10-22-2021, 04:04 PM)Here is the dump of \alsacap Wrote: Code: pi@moode:~ $ alsacap
*** Scanning for playback devices ***
Card 0, ID `b1', name `bcm2835 HDMI 1'
Device 0, ID `bcm2835 HDMI 1', name `bcm2835 HDMI 1', 4 subdevices (4 available)
1..8 channels, sampling rate 8000..192000 Hz
Sample formats: U8, S16_LE
Buffer size range from 80 to 131072
Period size range from 80 to 131072
Subdevice 0, name `subdevice #0'
Subdevice 1, name `subdevice #1'
Subdevice 2, name `subdevice #2'
Subdevice 3, name `subdevice #3'
Card 1, ID `Headphones', name `bcm2835 Headphones'
Device 0, ID `bcm2835 Headphones', name `bcm2835 Headphones', 4 subdevices (4 available)
1..8 channels, sampling rate 8000..192000 Hz
Sample formats: U8, S16_LE
Buffer size range from 80 to 131072
Period size range from 80 to 131072
Subdevice 0, name `subdevice #0'
Subdevice 1, name `subdevice #1'
Subdevice 2, name `subdevice #2'
Subdevice 3, name `subdevice #3'
Card 2, ID `Audio', name `NAD USB Audio'
Device 0, ID `USB Audio', name `USB Audio', 1 subdevices (1 available)
2 channels, sampling rate 44100..384000 Hz
Sample formats: S16_LE, S32_LE, SPECIAL
Buffer size range from 16 to 262144
Period size range from 8 to 131072
Subdevice 0, name `subdevice #0'
Tim CurtisThe fact that amixer does not report anything for USB device at card 2 is not normal. There should be information about the USB audio device in its output.
Another command that can be used to probe audio device capabilities is below.
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