[kwlug-disc] USB Microphone not working on Linux

[Khalid Baheyeldin]

Found the solution.

It is pavucontrol that is causing the 'Device or resource busy' error
message. So it has to be closed.

And to explicitly use a specific device, one has to use the syntax:

$ arecord -t wav -f cd -D plughw:1,0 | lame - file.mp3

(meaning: card 1, device 0)


On Sun, May 7, 2017 at 10:08 PM, Khalid Baheyeldin <kb at 2bits.com> wrote:

> I want to record something on my laptop (audio only).
>
> I plugged in an external headphones, and I can record using:
>
> $ arecord -t wav -f cd | lame - out.mp3
>
> And play it back successfully using:
>
> $ lame --mp3input --decode out.mp3 - | aplay
>
> Lame is just used to compress the audio stream.
>
> But when I plug in a USB microphone, it does not become the default
> device, nor does it work when explicitly specified on the arecord command
> line:
>
> $ arecord -t wav -f cd -D hw:1,0 | lame - out.mp3
>
> arecord: main:722: audio open error: Device or resource busy
>
> When checking which process has this device open, it turns out to be
> pulseaudio itself:
>
> $ fuser /dev/snd/controlC1
> /dev/snd/controlC1:  23708
>
> $ ps -ef | grep 23708
> kbahey   23708  1987  0 20:08 ?        00:00:28 /usr/bin/pulseaudio
> --start --log-target=syslog
>
> All this is despite Linux recognizing the device:
>
> [28358.940193] usb 6-2: new full-speed USB device number 5 using uhci_hcd
> [28359.135232] usb 6-2: New USB device found, idVendor=046d, idProduct=0a03
> [28359.135241] usb 6-2: New USB device strings: Mfr=1, Product=2,
> SerialNumber=0
> [28359.135246] usb 6-2: Product: Logitech USB Microphone
> [28359.135250] usb 6-2: Manufacturer: Logitech
>
> And in pavucontrol, the microphone is shown, and the blue bar shows that
> it is picking up sound when I speak near it, or when I type on the keyboard.
>
> I could forsake the command line and use Audacity, but there is no way to
> configure the USB mic in it. Under Preferences -> Devices -> Recording, the
> options are only 'default' and 'pulse'. That is all.
>
> I searched online, but nothing helped.
>
> Any help appreciated.
> --
> Khalid M. Baheyeldin
> 2bits.com, Inc.
> Fast Reliable Drupal
> Drupal optimization, development, customization and consulting.
> Simplicity is prerequisite for reliability. --  Edsger W.Dijkstra
> Simplicity is the ultimate sophistication. --   Leonardo da Vinci
> For every complex problem, there is an answer that is clear, simple, and
> wrong." -- H.L. Mencken
>



-- 
Khalid M. Baheyeldin
2bits.com, Inc.
Fast Reliable Drupal
Drupal optimization, development, customization and consulting.
Simplicity is prerequisite for reliability. --  Edsger W.Dijkstra
Simplicity is the ultimate sophistication. --   Leonardo da Vinci
For every complex problem, there is an answer that is clear, simple, and
wrong." -- H.L. Mencken
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