Airplay doesn't work with asynchronous DAC!

Sorry I cross-posted this, but I realized this may be a bug.

When I try to stream from my laptop to Volumio with Airplay (through Airfoil) to my Meridian Explorer asynchronous USB DAC, the artist sounds like a martian! The sound is heavily distorted; a kind of nasal, scrambled sound with a high pitch. Otherwise, playing through the Volumio interface to the Meridian from my NAS works like a charm. Airplay works fine with my IQAudio i2s DAC.

Laptop: HP G72
OS: Windows 7
Volumio 1.41
Airfoil 3.6.1
USB DAC Meridian Explorer

It seems all the shairplay devs are using the cheap 16bit usb dacs. Since airplay is 16bit this works perfectly when using “hw” as these dacs use s16_le. But async dacs tend to either support s24_le or s32_le only so you ned to edit the script in /etc/init.d/shairplay and replace hw with plughw. mpd has built in format conversion, but shairplay does not. Plughw let’s alsa take care of the format conversion.

Thanks, Soli! Do I just replace the word: ‘hw’ for ‘plughw’ in the file: ‘shairplay’? (I am a Linux rookie)

UPDATE: I only have a file ‘shairport’ in init.d. It does not contain the word: ‘hw’.

No, shairport is launched in player_wrk.php

So you have to edit this file, looking for the shairport launch script (with nano use shift+w to search) … Let me know if you need more info!

Where can I find that file?


Im actually not using Volumio, but the symptoms described i can remember from my own experience making my own server (but with normal Debian). Maybe michelangelo can update this for newer releases if my theory is right.