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DISTRHO / DISTRHO-Ports

Linux audio plugins and LV2 ports
http://distrho.sourceforge.net/ports
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High DSP usage and audio crackling with multiple instances (~10+) of TAL Filter 2 on Ardour 6 #57

Closed Tremeschin closed 4 years ago

Tremeschin commented 4 years ago

I've noticed that with big projects of mine on the Ardour DAW as I keep adding TAL Filter 2 ported by you guys for easy sidechaining (reaaal life saver plugin for quick productions), the audio will "crackle" a lot on small buffer sizes on Jack Audio.

Normally on old big projects before I found about TAL plugins, the DSP usage is just normal, 256 samples and < 20% usage with lots of synths and pads, however even on medium or ongoing projects I have to set the jack_bufsize to a value at least of 4096, that is 85.3ms of audio delay.

It is not the worst for a DAW but having to constantly switching over to 256 can get a bit annoying, considering that if I forget to put a high buffer size Ardour usually crashes when changing so while it's open on a project (happens ~30% the time).

This "audio crackle" can be explained as: "work well 0.8 seconds, stop for 0.2 seconds" (not on scale), this "stop for 0.2 seconds" changes depending on if I choose under Cadence advanced options to use "Server synchronous mode", if it's turned ON, the whole audio of Ardour stops, if it is OFF, the audio crackles like a vinyl disk but it can be recognized.

I'm not really sure if it's directly TAL Filter 2 being stubborn or any config problem in my setup, by running realtimeconfigquickscan only the swappiness and rt kernel are not good (I don't like changing the default swappiness and rt kernel had no difference for me so I use other kernel because the scheduler).

Thanks for any advice.

Tremeschin commented 4 years ago

I investigated this a bit further and it really wasn't TAL Filter 2 having huge DSP usage but instead Dragonfly Room Reverb.

I had suspicions it was TAL Filter 2 because it took a while to open whilst Dragonfly opens instantly, issue happen on both Jack Audio (jack and jack2 versions), and ALSA on Ardour.

I'm sorry for not testing (properly) before reporting and trusting too much my intuition, will report and check if other people have this same issue on their products.