Audio

This guide will show you how to connect and use a headset/microphone in order to exercise some of the available audio interfaces supported on the development kit.

Requirements

Ethernet Cable (Included in development kit)
Headphone/Microphone device with a standard 2.5mm Audio Jack connection (individual or combo)

Playing Audio

For this example, you’ll need the phyCORE-i.MX8X development kit connected to the internet. Checkout the Ethernet guide first!
Next, plug your headphones into the “Headphone (Default)” port (the black headphone jack).

Use the “wget” command to download a sample .wav file from the music science web server at the University of Helsinki directly to the development kit.

Target (Linux)

wget http://www.music.helsinki.fi/tmt/opetus/uusmedia/esim/a2002011001-e02.wav

Expected Output

a2002011001-e02.wav  100% |********************************| 9356k  0:00:00 ETA
'a2002011001-e02.wav' saved

Use the “aplay” command to play the audio

Target (Linux)

aplay a2002011001-e02.wav

Expected Output

Playing WAVE 'a2002011001-e02.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

Capturing Sound

Connect the microphone into the Pink jack.
Use the “arecord” command to capture audio at this interface. The command below will record sound for 10 seconds and save it to the file testrecord.wav.
Target (Linux)
```
arecord -d 10 -f cd -t wav testrecord.wav
```

Expected Output

Recording WAVE 'testrecord.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

Use the following to playback the file you just recorded:
Target (Linux)
```
aplay testrecord.wav
```

Expected Output

Playing WAVE 'testrecord.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

Adjusting Playback and Capture Settings

The alsamixer program can be used to configure sound devices and do things such as change volume or mute particular interfaces.

Tip

More information about alsamixer can be found here: https://linux.die.net/man/1/alsamixer

Launch alsamixer in the target console:
Target (Linux)
```
alsamixer
```
A GUI interface will pop up which can be navigated using arrow keys and the hotkeys.