Drop outs with zita bridge in Cadence

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lilith
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Drop outs with zita bridge in Cadence

Post by lilith »

When I was using KXStudio 14.04 I was able to use the zita bridge to route sound from the browser to Jack and it worked fine.
Now on Debian (+ KXrepos) I basically use pulse audio which works fine too.
With the alsa bridge I get crackles and high frequency distortions, so it's not really useful. However sound is without drop outs.
When I switch to the zita bridge the sound quality is very good but I get very long drop outs (~500 ms -1s). This also happens with a RT kernel or with the standard Debian kernel. If I increase the buffer size from 512 to 2048 it's fine.
My question is: What can cause the alsa bridge to work, but the zita bridge not. Are there any settings which only affect one of the bridges?
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Re: Drop outs with zita bridge in Cadence

Post by lilith »

falkTX wrote:I never got zita bridge to work too well, seems to require an alsa program to be making noise before it actually starts.
But I did not test much.

alsa_in/out having less quality is intentional, to keep CPU usage low as the daemon is running all the time in the background.
I should add an option for the resampling quality of that bridge, but when using pulseaudio it is not a problem, so I dont feel any rush to do it.
Considering alsa-only applications are now quite rare, using pulseaudi+jack just makes more sense.
The strange thing is, that it worked great on KXStudio 14.04 (ok, not that great ... I always had to start the alsa-bridge and open/close/open the browser, start/stop jack ... to get sound from zita) ... Aslong pulse is working fine I leave it like it is. Just wondered what the problem is ...
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Re: Drop outs with zita bridge in Cadence

Post by bluebell »

falkTX wrote:I never got zita bridge to work too well, seems to require an alsa program to be making noise before it actually starts.
But I did not test much.

alsa_in/out having less quality is intentional, to keep CPU usage low as the daemon is running all the time in the background.
I should add an option for the resampling quality of that bridge, but when using pulseaudio it is not a problem, so I dont feel any rush to do it.
Considering alsa-only applications are now quite rare, using pulseaudi+jack just makes more sense.
I use alsa_out to drive my monitor speakers (2x KH120A, 1x KH805 subwoofer) and the sound quality is perfect.

Where should a lower quality come from?

Linux – MOTU UltraLite AVB – Qtractor – http://suedwestlicht.saar.de/

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Re: Drop outs with zita bridge in Cadence

Post by lilith »

Can we switch computers and the monitoring setup? :mrgreen:

Alsa bridge is crackling since I use it and that happened with kxstudio 14.04 and on debian. I can't believe it's normal. But beside of the crackling the sound of the zita bridge is better. You will hear the difference with sine tones or by looking at the signal of sine tones. The alsa bridge is adding some higher harmonics (distortion) to the fundamental.
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Re: Drop outs with zita bridge in Cadence

Post by Jack Winter »

lilith wrote:Can we switch computers and the monitoring setup? :mrgreen:

Alsa bridge is crackling since I use it and that happened with kxstudio 14.04 and on debian. I can't believe it's normal. But beside of the crackling the sound of the zita bridge is better. You will hear the difference with sine tones or by looking at the signal of sine tones. The alsa bridge is adding some higher harmonics (distortion) to the fundamental.
FWIW, I've played years with the alsa jack plugin as well as the alsa loopback device together with alsa_in/out & zita-ajbridge. Admitted I've tried to make it run with JACK at low latency settings, and to be honest I've never been happy with the results.

I don't know much about pulseaudio, but since my distro uses it, I just load the right pulseaudio modules and it connects to my JACK1 server without any real issues. Seems to work fine from this point of view.
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