Preferences - Sound Hardware, JACK on alsa (no pipewire): Multi-Soundcard Synchronization and Engine Clock no more changeable

[JS-OnAir]

Feature Description

After the version-jump from 2.3.3 to 2.5.0
i am not any more able to choose these 2 preferences, if the

• Sound API: is set to 'JACK Audio Connection Kit':

• Multi-Soundcard Synchronization:
  unchangeable greyed out, setting: 'Default (long delay)', would set to clear sound with 'Experimental (no delay)'

• Engine Clock:
  unchangeable greyed out, setting: cheap 'Soundcard Clock', would set to better 'Network Clock' (DAC)
  If both soundcards now work independent with their own clock, should be an other text there.

I don't find any cause for this setting in the issues history.

With this settings above, in Jack the highest possible sample rate and an active dither 'triangle' could i get the clearest sound in the past!

[daschuer]

I am afraid that Multi soundcard synchronization never worked on 2.3.3. In 2.5 we have made it visible. Pipewire has a multy soundcard synchronization feature. So you maybe want to switch to that. On which Distro and version are you?

We are currently working on a native pipewire backend that aims to replace Jack. You may want to help testing?
@pri-yan-shu

[JS-OnAir]

I have LMDE running.

With Pipewire i had very bad experiences:
It sounds like 60 % of possible quality. Better than pure ALSA, but no sharpness, no details in the sound. The flac files, feels like a 64k-mp3!
The Pipewire- jack was unusable wile my tests in the past. So i kicked it and was go back to good old ALSA and Jack.

A very important feature in jack is dither. Without this, i can go back to MS Windows with a to 48 kHz neutered asio4all! X-(
Please don't replace Jack!

Multi sound card synchronization never worked (in v 2.3.3)?
I used long time mixxx v 2.2.4 over SPdif to an DAC with a ess 32 sabre chip and i could hear huge differences between the Experimental adjustment 'no delay' and the other! What happens?

The idea to choose the Network-clock is less to sync multi sound card's. It is for the external DAC can use its own well clock to decode the bit stream instead of with the jittering pulses from a sloppy onboard sound- card- clock.

To real check and analyze the quality of given sound it must be re- recorded and encoded with 192 kHz and 24 bit. Such well hardware is not my own.
No people can hear 96 or 192 kHz, but can hear a distortion and jitter wide over 96 kHz of a 8 kHz tone!

With my less time i am not sure that i can compile alpha- versions to test it.
But i will have an eye on it. At a silent hour i like to help, if i can.

[JS-OnAir]

@daschuer 🥇 Much thank's for the inspiration!

On my new system i switched back to old mixxx 2.2.4 from debian archive bullseye and reach the wonderful sound also here!

The changes in the 4 sound-hardware adjustments

• Sound API: is set to 'JACK Audio Connection Kit'
• output device: set to system, channels 1 - 2
• Multi-Soundcard Synchronization: set to 'Experimental (no delay)'
• Engine Clock: set to 'Network Clock' (DAC)

must accepted one by one. Else i get often the case, that not all is right taken.
Now enjoy!

Still the big question:
What kill's the quality in the newer versions?

[JS-OnAir]

New feature 'native pipewire backend':

• Where i can find and follow this work?

• To Pipewire and possible quality i found:
  https://www.linuxdj.com/notes/pipewire-jack-vs-native-jack-in-2026/

Server Mean callback jitter Max callback jitter
PipeWire JACK (quantum 128) 12 us 48 us
Native JACK2 (period 128) 8 us 31 us

As feature is the native pipewire backend well, but under this conditions, not for replacement!

• Important, i think, is to find the cause of the sound quality issues after v 2.2.4 and to fix it!

[pri-yan-shu]

Here is the proposal for PipeWire work, you can test it using the --developer flag while running Mixxx built from Main branch.