Raspberry Pi, USB Audio Card and 3.5mm Microphone

[pierreee1]

Hello, I've been trying to use this USB Audio card: https://http2.mlstatic.com/tarjeta-de-s ... 019-F.webp as sound output and input.

I followed this tutorial: https://www.raspberrypi-spy.co.uk/2019/ ... pberry-pi/ and the output works as expected but when I try to record something using a 3.5mm microphone in the other socket, (https://http2.mlstatic.com/microfono-cl ... ti-ruido-D_)NQ_NP_657504-MCO31018242764_062019-F.webp) it only creates blank files. I think it's not getting any information from the mic.

Do I need to configure anything else?

I used the following command to record:

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arecord --device=hw:1,0 --format S16_LE --rate 44100 -c1 -V mono test.wav

These are the cards the Pi recongnizes:

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0 [ALSA]: bcm2835_alsa - bcm2835 ALSA bcm2835 ALSA
1 [Device]: USB-Audio - USB PnP Sound Device C-Media Electronics Inc. USB PnP Sound Device at usb-3f980000.usb-1.4, full spe

The capture devices:

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**** List of CAPTURE Hardware Devices ****
card 1: Device [USB PnP Sound Device], device 0: USB Audio [USB Audio]
Subdevices: 1/1
Subdevice #0: subdevice #0

And the mixer info:

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Simple mixer control 'Speaker',0
 Capabilities: pvolume pswitch pswitch-joined
 Playback channels: Front Left - Front Right
 Limits: Playback 0 - 151
 Mono:
 Front Left: Playback 64 [42%] [-16.38dB] [on]
 Front Right: Playback 64 [42%] [-16.38dB] [on]
Simple mixer control 'Mic',0
 Capabilities: pvolume pvolume-joined cvolume cvolume-joined pswitch pswitch-joined cswitch cswitch-joined
 Playback channels: Mono
 Capture channels: Mono
 Limits: Playback 0 - 127 Capture 0 - 16
 Mono: Playback 75 [59%] [14.06dB] [off] Capture 16 [100%] [23.81dB] [on]
Simple mixer control 'Auto Gain Control',0
 Capabilities: pswitch pswitch-joined
 Playback channels: Mono
 Mono: Playback [on]

[mahjongg]

Perhaps the USB sound card does not provide the few volts BIAS voltage that most simple FET element microphones need to work.
Try another audio source, like your smartphone with a 3.5mm to 3.5mm adapter cable.

[pierreee1]

I tried recording sound from a phone using the 3.5to3.5mm cable but still no luck. It doesn't record anything.

[drgeoff]

Are you sure the Mic is not muted in ALSA mixer?