How do I change Alsa sample format from 24bit int to 32

andie · November 23, 2021, 9:01pm

Hi!
I’m setting up supercollider on a new computer, and sound is working but sounding … weird.

Examining the startup patter, I notice

ALSA: final selected sample format for capture: 24bit little-endian

while on my old computer it’s 32 bit.
I haven’t been able to find out where to change this. Does anyone know how to fix this issue?

Thank you!

jamshark70 · November 23, 2021, 10:24pm

Could you be more specific? “Weird” could be anything, so there’s no way to make a meaningful guess as to the cause.

Is it only JACK apps, or all audio? Specific soundcards or all of them?

As I understand it, JACK and ALSA are supposed to abstract the hardware sample format away from you. It’s entirely normal for ALSA to select an integer format and shouldn’t be necessary to be float here; SC and JACK will continue to use floats internally.

hjh

andie · November 24, 2021, 12:43am

(Sorry if you got an incomplete version of this, I accidentally sent too soon)

Thanks for helping me look into this!

Youtube sounds normal, Timidity sounds normal, Reaper sounds normal (PulseAudio). I’m not sure how to check for JACK apps in particular.

What I meant by “weird” on supercollider: I was testing with {SinOsc.ar(x,0,0.2)}.play –
x = 300 sounds like sharp tone at 300hz (NOT a sine)
x = 440 sounds like buzzy oscillator 80hz
x = 800 sounds like sharp tone at 800 hz
x = 900 sounds like sharp tone at 600 hz

This kind of behavior is part of why I thought numbers were just being interpreted wrong e.g. interpreted in 24 bits rather than the expected 32, as it seems to say in my start up dialog.

andie · November 24, 2021, 12:47am

As far as I know I just have the one built-in soundcard. I did try all of the different interfaces in qjackctl. The computer is a new Dell XPS 13, running the latest Linux Mint.

jamshark70 · November 24, 2021, 2:15pm

What are all of your JACK settings and server options? Especially these:

JACK: Sample rate, buffer size, periods per buffer
s.options.blockSize

hjh

andie · November 24, 2021, 2:46pm

s.options.blockSize is 64
JACK samplerate was 44100, tried changing it to 48000 to match sc, sounds the same as before.
JACK Frames/Period is 1024, Periods/Buffer is 2.

jamshark70 · November 25, 2021, 12:13am

I have to admit, I don’t have a solid idea what’s going on.

How to check JACK apps… Reaper can play through JACK, if you’re using the native Linux version instead of the Windows version with Wine.

If Reaper → JACK and SC → JACK both sound bad, then it would be a JACK configuration problem.

If Reaper → JACK sounds ok while SC does not, then it gets interesting.

What does the waveform look like for the bad sine waves?

hjh

andie · November 25, 2021, 5:15pm

The waveform looks exactly as it should.

I think it’s a JACK problem, not a SuperCollider problem. In fact, I’m pretty sure it’s clipping – somewhere along the line the signal is being multiplied by a lot. SinOsc.ar(440,0,0.0002) sounds about right.

None of the JACK configurations seem to be wrong, though, and I don’t see a place to add a multiplier to JACK to counteract this. Maybe it’s some audio driver issue causing this… Still looking into it…

andie · November 29, 2021, 2:56pm

Just to follow up on this – I ended up installing pipewire (an odyssey in itself) which seems to have solved the problem.

Peter · November 29, 2021, 4:17pm

andie via scsynth noreply@m.scsynth.org [2021-11-29 16:05]:

Just to follow up on this – I ended up installing pipewire (an odyssey in itself) which seems to have solved the problem.
Have you ever asked about your problem on the Linux Audio Users mailing
list yet?

Peter · November 29, 2021, 4:30pm

andie via scsynth noreply@m.scsynth.org [2021-11-29 16:05]:

Just to follow up on this – I ended up installing pipewire (an odyssey in itself) which seems to have solved the problem.

Have you ever asked about your problem on the Linux Audio Users mailing
list yet?
(retrying from mailing list mode with different formatting now)

flechtwerk · November 29, 2021, 4:54pm

I’m curious about your experience there (or from anyone else who has switched to Pipewire). I ran into heavy xrun issues when trying out Pipewire for the first time a few weeks ago, so I reverted to my beloved JACK… I thought Pipewire wasn’t ready yet, but it seems some people are using it just fine.

andie · November 29, 2021, 9:46pm

I did not ask on the Linux Audio Users mailing list. I was looking at the linuxaudio subreddit, but didn’t end up posting there either. Their discussion of pipewire was helpful though!

I found a few mentions of the problem various places onlline, never with any solution (other than pipewire).

github.com/tidalcycles/Tidal

Audio samples being outputed super distorted

opened 12:44AM - 22 Oct 21 UTC

closed 03:23PM - 07 Nov 21 UTC

tiagohermano

I just installed SuperCollider (v3.11.2) and tidal("1.7.8) in my new system, a D…ell XPS 13 running Pop_os 21.04. I got this weird issue where all the samples are playing super clipped and distorted. #### I've already tried. - Reinstalling tidal and SuperCollider through different methods; - Changing my jack audio configuration (Audio interface, sampling rate, frames per period and period/buffer); - Changing the audio interface and volumes in alsamixer - Disabling the battery saving and thermal throttle options in the BIOS configuration (suggested by a kind user in the discord community) ### startup.scd ```scd /* This is an example startup file. You can load it from your startup file (to be found in Platform.userAppSupportDir +/+ "startup.scd") */ ( s.reboot { // server options are only updated on reboot // configure the sound server: here you could add hardware specific options // see http://doc.sccode.org/Classes/ServerOptions.html s.options.numBuffers = 1024 * 256 * 4; // increase this if you need to load more samples s.options.memSize = 8192 * 32 * 4; // increase this if you get "alloc failed" messages s.options.numWireBufs = 64; // increase this if you get "exceeded number of interconnect buffers" messages s.options.maxNodes = 1024 * 32 * 4; // increase this if you are getting drop outs and the message "too many nodes" s.options.numOutputBusChannels = 2; // set this to your hardware output channel size, if necessary s.options.numAudioBusChannels = 1024 * 4; s.options.numInputBusChannels = 2; // set this to your hardware output channel size, if necessary // boot the server and start SuperDirt s.waitForBoot { ~dirt = SuperDirt(2, s); // two output channels, increase if you want to pan across more channels ~dirt.loadSoundFiles; // load samples (path containing a wildcard can be passed in) // for example: ~dirt.loadSoundFiles("/Users/myUserName/Dirt/samples/*"); // s.sync; // optionally: wait for samples to be read ~dirt.start(57120, 0 ! 12); // start listening on port 57120, create two busses each sending audio to channel 0 // optional, needed for convenient access from sclang: ( ~d1 = ~dirt.orbits[0]; ~d2 = ~dirt.orbits[1]; ~d3 = ~dirt.orbits[2]; ~d4 = ~dirt.orbits[3]; ~d5 = ~dirt.orbits[4]; ~d6 = ~dirt.orbits[5]; ~d7 = ~dirt.orbits[6]; ~d8 = ~dirt.orbits[7]; ~d9 = ~dirt.orbits[8]; ~d10 = ~dirt.orbits[9]; ~d11 = ~dirt.orbits[10]; ~d12 = ~dirt.orbits[11]; ); }; s.latency = 0.3; // increase this if you get "late" messages }; ); ``` I'm super new to SuperCollider, tidal and Linux audio servers. If there are some valuable pieces of informations that I should be sharing here, please let me know.

I dd post an issue to the github for Jack, though I’m not sure how useful this will turn out to be. https://github.com/jackaudio/jack2/issues/816#issuecomment-981974055

Right now
I’m no longer trying to debug this, as pipewire seems ok (though I haven’t tested extensively). But if I get back to this problem I’ll try the Linux Audio Users group!

andie · November 29, 2021, 9:51pm

Well, I just did a bare minimum test to see that my initial problem was gone, and I have sound that sounds correct. I still have to install the rest of my stuff and do more testing!

That said, my stuff is pretty much all NRT, except for some small testers. If I understand correctly, xruns are more of a problem with real-time / interaction. If there’s a stress-test script I could run to see if I get xruns, I’d be happy to do that.

A few of the people over at r/linuxaudio seem to be happy with pipewire, but I’m not sure if I saw anything supercollider specific. It may be worthwhile starting a separte topic here to see who’s all using Pipewire.