Microphone Test

GoogleGroups
1

Hi,
I am testing microphone on Beagleboard.

[root@beagleboard /]# arecord -t wav -c 1 -d 5 -r 8000 -f S16_LE -v rec_8000.dat Recording WAVE ‘rec_8000.dat’ : Signed 16 bit Little Endian, Rate 8000 Hz, Mono
Plug PCM: Route conversion PCM (sformat=S16_LE)
Transformation table:
0 ← 00.5 + 10.5
Its setup is:
stream : CAPTURE
access : RW_INTERLEAVED
format : S16_LE
subformat : STD
channels : 1
rate : 8000
exact rate : 8000 (8000/1)
msbits : 16
buffer_size : 4000
period_size : 1000
period_time : 125000
tick_time : 0
tstamp_mode : NONE
period_step : 1
sleep_min : 0
avail_min : 1000
xfer_align : 1000
start_threshold : 1
stop_threshold : 4000
silence_threshold: 0
silence_size : 0
boundary : 2097152000
Slave: Hardware PCM card 0 ‘omap3beagle’ device 0 subdevice 0
Its setup is:
stream : CAPTURE
access : MMAP_INTERLEAVED
format : S16_LE
subformat : STD
channels : 2
rate : 8000
exact rate : 8000 (8000/1)
msbits : 16
buffer_size : 4000
period_size : 1000
period_time : 125000
tick_time : 0
tstamp_mode : NONE
period_step : 1
sleep_min : 0
avail_min : 1000
xfer_align : 1000
start_threshold : 1
stop_threshold : 4000
silence_threshold: 0
silence_size : 0
boundary : 2097152000
[root@beagleboard /]# aplay -t wav -c 2 -r 8000 -f S16_LE -v rec_8000.dat
Playing WAVE ‘rec_8000.dat’ : Signed 16 bit Little Endian, Rate 8000 Hz, Mono
Plug PCM: Route conversion PCM (sformat=S16_LE)
Transformation table:
0 ← 0
1 ← 0
Its setup is:
stream : PLAYBACK
access : RW_INTERLEAVED
format : S16_LE
subformat : STD
channels : 1
rate : 8000
exact rate : 8000 (8000/1)
msbits : 16
buffer_size : 4000
period_size : 1000
period_time : 125000
tick_time : 0
tstamp_mode : NONE
period_step : 1
sleep_min : 0
avail_min : 1000
xfer_align : 1000
start_threshold : 4000
stop_threshold : 4000
silence_threshold: 0
silence_size : 0
boundary : 2097152000
Slave: Hardware PCM card 0 ‘omap3beagle’ device 0 subdevice 0
Its setup is:
stream : PLAYBACK
access : MMAP_INTERLEAVED
format : S16_LE
subformat : STD
channels : 2
rate : 8000
exact rate : 8000 (8000/1)
msbits : 16
buffer_size : 4000
period_size : 1000
period_time : 125000
tick_time : 0
tstamp_mode : NONE
period_step : 1
sleep_min : 0
avail_min : 1000
xfer_align : 1000
start_threshold : 4000
stop_threshold : 4000
silence_threshold: 0
silence_size : 0
boundary : 2097152000
[root@beagleboard /]#

No sound on the recorded file. But if I play any wav file is working fine.

with regards,
saminath

2

  I am testing microphone on Beagleboard.

Try using amixer to set the mic's volume:

amixer -c 1 set Mic 100%

Jan

3

Note that BBxM does not have a pre-amp and does not power mics. So
you'd have to power it and amplify the signal. Audio input in the BBxM
is a "line in". If your board is not xM, then you'd not have this
problem.

Rafael

4

Dear Rafeel,

I am also checking the Hardware issue,

amixer sset ‘Analog’,0 100%,100% unmute
amixer sset ‘Analog Left’ AUXL

amixer sset ‘Analog Right’ AUXR

After this setting it is able to capture using arecord,
But aplay giving some junk output only.

with regards,
saminath