Airplay distortion over USB

Cyclopse

I output direct from Rasberry Pi USB to my USB DAC.

Only bug I have is very bad distortion playing Apple Music over Airplay.

I have read the post from Tret that recommends changing one of the lines of code. I am OK accessing the SSH through Putty but am lost from there.

Can anyone list step by step where I go from there to change and save one of the lines of the programme?

Thanks

Steve

hondagx35

Hi Steve,

it would be very helpfull to know a bit more about your setup.

- Pi model (RP1, RP2 or RP3)?
- RuneAudio version?

I'm asking, because if you have a RP2 or RP3 it would be enought to update the installation.

cd /var/www
git stash
git pull

And after that toggle Airplay once in the setup (on / off with save).

Frank

Cyclopse

Hi Frank,

I am running Pi 2 and Rune version 0.3 Beta. So I just need to input those commands you stated through Putty?

Thanks

Steve

hondagx35

yes

Cyclopse

Changed to 0.4 Beta for my Pi 2.

Distortion is back when playing Apple Music via Airplay. I have sound on the Meitner DAC, USB input but heavily distorted.

To be honest I have never fully cracked this. When changing the code as follows I get a short click every few seconds;-

ExecStart=/usr/bin/shairport -w –name=runeaudio –on-start=$ON –on-stop=$OFF –meta-dir=/var/run/shairport -o alsa — -d plughw:1,0

I would welcome your input Frank.

Superb project appart from this frustration.

Regards

Cyclopse

hondagx35

Hi Cyclopse,

modify the file /usr/share/alsa/alsa.conf

defaults.pcm.ipc_gid audio
defaults.pcm.ipc_perm 0660
defaults.pcm.dmix.max_periods 0
defaults.pcm.dmix.rate 48000
defaults.pcm.dmix.format "unchanged"
defaults.pcm.dmix.card defaults.pcm.card
defaults.pcm.dmix.device defaults.pcm.device
defaults.pcm.dsnoop.card defaults.pcm.card
defaults.pcm.dsnoop.device defaults.pcm.device
defaults.pcm.front.card defaults.pcm.card
defaults.pcm.front.device defaults.pcm.device

defaults.pcm.dmix.rate 44100

Frank

Cyclopse

Hi Frank,

Amended the entry 4800 to 44100 as advised. Did a reboot and toggled AirPlay in Rune. Tried tonight but no change to AirPlay audio. Still heavily distorted. Should I try a different value?

Thanks

Cyclopse

hondagx35

Hi Cyclopse,

Tried tonight but no change to AirPlay audio.

On my system with a HifiberryDAC+ it works without problems even without the changes.

What is the output from

cat /proc/asound/card*/pcm*p/sub*/hw_params

while playing via Airplay?

Frank

Cyclopse

Hi Frank,

The output was;-

closed
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access: RW_INTERLEAVED
format: S32_LE
subformat: STD
channels: 2
rate: 44100 (44100/1)
period_size: 64
buffer_size: 65536

Thanks

Steve

hondagx35

Hi Steve,

the "period_size" looks way too low in my eyes.

Let me see how to set this parameter.

Frank

Cyclopse

I got a fix for this. Something I was doing forced a move over to the US app store. Couldn't change the setting back unless you cancel your Apple Music subscription. (Seems a strange way to run a business). Now using Spotify Premium. No distortion and great integration with Rune.

fabiomoska

hondagx35 wroteHi Steve,

the "period_size" looks way too low in my eyes.

Let me see how to set this parameter.

Frank

Hi Frank. Having the same problem here running Rune on pi3 and a ROTEL USB DAC.
I ran the hw_params comman and got 512 in the period_size parameter.

Any hints?