Check Headphone sound

Hi there,

I’ve recently found this project, I’m getting the first steps to bring it Zynthian up.
First of all congratulations to everyone involved for this such a project!

I have a Raspberry Pi4 and I installed ZynthianOS Nightly Builds, more preciselly 2021-02-27 build.

I’ve followed these instructions and I have the board up and running, no Zythian hardware yet.

The Raspberry PI4 has 2 audio interfaces, HDMI and Headphones. I configured the board to use the Headphones on Webconf. However, I’m not sure which interface is using by default ZynthianOS.

I made a simple test, I connected to the board through ssh

# list interfaces
aplay -L

# Here I see many entries, but basically 2 interfaces:
#   default:CARD=b1
#       bcm2835 HDMI 1, bcm2835 HDMI 1
#       Default Audio Device
#   default:CARD=Headphones
#       bcm2835 Headphones, bcm2835 Headphones
#       Default Audio Device

# Generate a pink noise with each card
speaker-test -Ddefault:b1 
speaker-test -Ddefault:Headphones

I’d want to check how which interface is using ZynthianOS by default.

I want to go step-by-step on the process of learning ZynthianOS :wink: I have access to the GUI-UI through VNC, but as I can’t yet generate any sound I want to be sure that sound configuration is fine.

Thanks a lot!

HI @sarean !!

Welcome to zynthian project. I’m pretty sure you will enjoy the crew, jeje …

Don’t do this. Use the latest stable SD image, please:


Thanks for your feedback @jofemodo !

First I tried the stable version, but the board wasn’t getting any IP address from my router, which has enabled dhcp. I scanned the net with nmap and it didn’t found the board, so I tried nightly version, which works fine in this aspect :wink:

I don’t have a micro-hdmi cable, but once I get it I’ll try again the stable version to figure out what was wrong.

Regarding my question, I assume that if everything is properly configured when calling speaker-test with no arguments, I should listen a pink noise in the headphones, shouldn’t I? That’s the behaviour I’d expect in a GNU/Linux system.

Hi @sarean !

The stable SD works perfectly on a raw RBPi with HDMI display. Wired network should work out-the box and you have to access the webconf for configuring your hardware (HDMI display, RBPi Headphones and dummy wiring).


@jofemodo thanks for guiding me in this initial steps. I’ve followed your recommendation and I installed the stable version, and as you mentioned works fine! I must had an issue in my network…

Going back to my initial question, how can I check if ZynthianOS is using the Headphone’s output by default? If I run speaker-test with no arguments it can’t open the sound device, and I must explicitly pass the device speaker-test -Ddefault:Headphones

@sarean Once Zynthian is running you can test your output by selecting the Test Audio option from its Admin menu. Use webconf http://zynthian.local to select the required audio interface by first deselecting Custom Kit in Hardware->Kit then selecting the required Soundcard in Hardware->Audio.

Zynthian uses jackd to manage sound. It opens the ALSA hardware drivers for the soundcard it is condigured to use so other applications won’t be able to use the audio interface directly, they will need to connect to jackd. It is not clear wyu you are trying to test the audio at the command line.

In the Zynthian user interface Admin menu there is also an option to send audio to the Headphone (onboard 3.5mm audio output) if Headphones is not selected as the main audio output but beware that this adds processsing load to Zynthian so it not recommended.

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Thanks @riban for the explanation, now it’s clear for me how and why things are working behind!

I’ve used cli, because I’m used to it :wink: I’ve tested it also with an usb soundcard and it works like a charm!

This looks very promising!