Re: testing microphone - how?

["H.S." <hs.samix@gmail.com>]

Emanoil Kotsev wrote:

> excuse me but you are not correct
> 
> use amixer
> 
> amixer | grep Input
> Simple mixer control 'Digital Input Source',0
>   Items: 'Analog Inputs' 'Digital Mic 1' 'Digital Mic 2' 'CD'
>   Item0: 'Analog Inputs'
> Simple mixer control 'Digital Input Source',1
>   Items: 'Analog Inputs' 'Digital Mic 1' 'Digital Mic 2' 'CD'
>   Item0: 'Analog Inputs'
> 
> and use alsamixer or similar to turn your mic on
> 
> If your driver is not properly configured you can have some options mixed up
> so play around
> 
> I'm personally using following to test input
> 
> 1) find out cards and inputs
> 
> shell> cat /proc/asound/cards
>  0 [Intel          ]: HDA-Intel - HDA Intel
>                       HDA Intel at 0xff950000 irq 22
>  1 [HVR900         ]: USB-Audio - WinTV HVR-900
>                       WinTV HVR-900 at usb-0000:00:1a.7-3, high speed
>  2 [Webcam         ]: USB-Audio - Philips SPC 1000NC Webcam
>                       Philips CE Philips SPC 1000NC Webcam at
> usb-0000:00:1a.7-5.4, high speed
> 
> => I'm going to use the Webcam built in mic => card # 2
> 
> 2) find out the input
> 
> shell> cat /proc/asound/devices
>   0: [ 0]   : control
>   1:        : sequencer
>   6: [ 0- 2]: hardware dependent
>   7: [ 0- 3]: hardware dependent
>  16: [ 0- 0]: digital audio playback
>  17: [ 0- 1]: digital audio playback
>  19: [ 0- 3]: digital audio playback
>  24: [ 0- 0]: digital audio capture
>  32: [ 1]   : control
>  33:        : timer
>  56: [ 1- 0]: digital audio capture
>  64: [ 2]   : control
>  88: [ 2- 0]: digital audio capture
> 
> 
> => my input is the capture on the second card
> 
>  88: [ 2- 0]: digital audio capture
> 
> 3) so no we can test the mic
> 
> shell> arecord -c1 -Dplughw:2,0 -f cd -vv /dev/null
> 
> Recording WAVE '/dev/null' : Signed 16 bit Little Endian, Rate 44100 Hz,
> Stereo
> Plug PCM: Route conversion PCM (sformat=S16_LE)
>   Transformation table:
>     0 <- 0
>     1 <- 0
> Its setup is:
>   stream       : CAPTURE
>   access       : RW_INTERLEAVED
>   format       : S16_LE
>   subformat    : STD
>   channels     : 2
>   rate         : 44100
>   exact rate   : 44100 (44100/1)
>   msbits       : 16
>   buffer_size  : 22050
>   period_size  : 5513
>   period_time  : 125011
>   tstamp_mode  : NONE
>   period_step  : 1
>   avail_min    : 5513
>   period_event : 0
>   start_threshold  : 1
>   stop_threshold   : 22050
>   silence_threshold: 0
>   silence_size : 0
>   boundary     : 1445068800
> Slave: Hardware PCM card 2 'Philips SPC 1000NC Webcam' device 0 subdevice 0
> Its setup is:
>   stream       : CAPTURE
>   access       : MMAP_INTERLEAVED
>   format       : S16_LE
>   subformat    : STD
>   channels     : 1
>   rate         : 44100
>   exact rate   : 44100 (44100/1)
>   msbits       : 16
>   buffer_size  : 22050
>   period_size  : 5513
>   period_time  : 125011
>   tstamp_mode  : NONE
>   period_step  : 1
>   avail_min    : 5513
>   period_event : 0
>   start_threshold  : 1
>   stop_threshold   : 22050
>   silence_threshold: 0
>   silence_size : 0
>   boundary     : 1445068800
> ###   +                                            | 10%^C
> Aborted by signal Interrupt...
> 
> regards
> 
> 


Wonderful explanation of the magic that alsa does! Thanks a ton. I
didn't know about "cat /proc/asound/devices" before.

Regards.

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