What to use Raspberry Pi 3 Model B+ USB microphone (Sanwa Supply USB microphone unidirectional direct insertion type MM-MCU02BK)

Microphone settings

Connect the microphone to the Raspberry Pi's USB port and make sure the microphone is recognized.

$lsusb

You can see that the top C-Media is recognized by the microphone.

Raise the priority of the microphone Check the priority of the audio module.

$ cat /proc/asound/modules
　0 snd_bcm2835
　1 snd_usb_audio

At first, 0 is the built-in audio module and 1 is the USB microphone, so rewrite the priority.

$ sudo nano /etc/modprobe.d/alsa-base.conf

Write the following code in the editor that opens.

options snd slots=snd_audio,snd_bcm2835
options snd_usb_audio index=0
options snd_bcm2835 index=1

Exit with ctrl + X and reboot.

$ reboot

After starting up, check the priority again, and if 0 is the USB audio module and 1 is the built-in audio module, it is successful.

$lsusb

Sound driver installation Install aptitude and then the ALSA sound driver. It seems that the raspberryPi3B + does not include the snd-pcm-oss module.

sudo apt-get install aptitude
sudo apt-get install osspd-alsa
sudo aptitude install libasound2-dev

Check the sound card number of the microphone.

$ arecord -l

Set environment variables so that you can always use the same settings.

$ sudo nano ~/.profile

Add the following code at the top or bottom of the opened editor, where it doesn't interfere with the code you're writing.

export ALSADEV=hw:0,0

Exit with ctrl + X and reboot.

$ reboot

Microphone setting is complete Next to Julius installation [Use julius (speech recognition) on raspberry Pi. ② Installation](https://qiita.com/chiapis2/items/7ec1b0b21ee4fef4e8f0)