On Monday, 13 April 2020 18:09:25 BST Jorge Almeida wrote:
> On Mon, Apr 13, 2020 at 4:29 PM Michael <confabul...@kintzios.com> wrote:
> > Yes, the first step would be to reduce or set to zero the Mic Boost in
> > alsamixer and adjust the Capture volume.  However, noise with arecord is
> > usually a result of incorrect bitrate?
> > 
> > You could try:
> > 
> > arecord -fdat -r 48 test.wav
> 
> OK, I tried "arecord -D hw:0,1 -fdat -r 48 test.wav" and "arecord -D
> hw:0,2 -fdat -r 48 test.wav". aplay produces noise, in both cases. I
> alse tried with -r 44, same result.
> 
> ## arecord -l
> **** List of CAPTURE Hardware Devices ****
> card 0: PCH [HDA Intel PCH], device 0: Generic Analog [Generic Analog]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
> card 0: PCH [HDA Intel PCH], device 2: Generic Alt Analog [Generic Alt
> Analog] Subdevices: 1/1
>   Subdevice #0: subdevice #0

I can't see your USB mic anywhere ...

Both device 0 and device 2 are on the *same* card.  I would think an external 
device as you posted previously would register on the kernel as a separate 
card.

Is dmesg recognising your USB mic when you plug it in?

Do you need some additional driver for it?

Is there some On/Off button on it you need to turn it on with?


> ## arecord -L
> null
>     Discard all samples (playback) or generate zero samples (capture)
> default:CARD=PCH
>     HDA Intel PCH, Generic Analog
>     Default Audio Device
> sysdefault:CARD=PCH
>     HDA Intel PCH, Generic Analog
>     Default Audio Device
> front:CARD=PCH,DEV=0
>     HDA Intel PCH, Generic Analog
>     Front speakers
> usbstream:CARD=PCH
>     HDA Intel PCH
>     USB Stream Output

Hmm ... I assume "USB Stream Output" is the USB mic, but I'm not sure and the 
Output part confuses me.


> I assume the two capture devices are LineIn and Mic (mono). Correct?
> (But why the device numbers 0 and 2, and not 1?)
> OTOH,
> ## arecord  -fdat -r 48 test.wav
> ALSA lib
> /var/tmp/portage/media-libs/alsa-lib-1.2.1.2/work/alsa-lib-1.2.1.2/src/pcm/
> pcm_dsnoop.c:641:(snd_pcm_dsnoop_open) unable to open slave
> arecord: main:828: audio open error: No such file or directory
> 
> I didn't use any flags for aplay, because aplay foo.wav works fine
> when foo.wav is music from a CD (i.e., not from a micro)
> 
> > Also, make sure any hardware buttons have been enabled and the mic is not
> > muted.  Additional options may be required to use the correct input device
> > and driver, which can be specified in /etc/modprobe.d/alsa.conf
> 
> I have /etc/modprobe.d/alsa.conf (not changed) but I have alsa support
> built in the kernel, not as a module (could this be a problem?!)
> 
> Jorge

Years ago I was having problems with alsa.  Audio drivers were not as polished 
as they are today for Linux.  Anyway, I remember contacting some dev who asked 
me to rebuild my kernel with alsa as modules and run 'alsactl init', which 
would only produce a full output this way.  I don't know if this would still 
be a problem today and anyway you are not experiencing the same bugs I was 
troubleshooting 15 years ago.

So, in the first instance I would look at a USB driver, if needed, from the 
output in dmesg.

lsusb -v would also show any 

        bInterfaceClass         1 Audio
        bInterfaceSubClass      1 Control Device

and any fields showing "Microphone".

Finally, have a look under 'cat /proc/bus/input/devices' or similar for any 
USB devices, to find out what driver it is using.

HTH.

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