Adding a USB Speaker to Raspberry Pi

I bought a simple USB speaker for my raspberry pi. I plugged it in and… it didnt work. Here is how to configure it.

Use arecord to record a sample, then use aplay to play it back and test the audio output. In my case the sound comes out the headphones but not the USB speaker.

arecord -Dac108 -f S32_LE -r 16000 -c 4 hello.wav
aplay hello.wav

In the home or root folder (e.g. home/pi/) there is file called .asoundrc which describes the audio configuration.

cd ~
sudo nano .asoundrc

This should bring up nano with a file like this:

pcm.!default {
  type asym
  playback.pcm {
    type plug
    slave.pcm "output"
  }
  capture.pcm {
    type plug
    slave.pcm "input"
  }
}

pcm.output {
  type hw
  card 0
}

ctl.!default {
  type hw
  card 0
}

Notice the card attributes are set to 0. Exit .asoundrc and then use aplay to list the available output devices

# Ctrl + X
aplay -l

You should see something like this…

pi@raspberrypi:~ $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Headphones [bcm2835 Headphones], device 0: bcm2835 Headphones [bcm2835 Headphones]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 1: Device [USB2.0 Device], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Here it says card 0 is the headphones, and the USB is card 1. In the configuration file the cards are set to 0 i.e. the headphones.

We need to change asoundrc to use card 1. Go back into .asoundrc in nano and change it.

sudo nano .asoundrc

pcm.!default {
  type asym
  playback.pcm {
    type plug
    slave.pcm "output"
  }
  capture.pcm {
    type plug
    slave.pcm "input"
  }
}

pcm.output {
  type hw
  card 1
}

ctl.!default {
  type hw
  card 1
}

Exit Nano and save it, then test it again. Using aplay hello.wav. If there is still no sound try and change the volume using the alsamixer

aplay hello.wav
alsamixer