Why does playing on channels higher then 0 and 1 saturate?

I’m new to SC, so please forgive the dumb question.
I’m trying to send audio to my DAW (Bitwig) through ASIO Link Pro.
Everything works fine if I use output channels 0 and 1, but when I set Out.ar to use higher channels it sorts of breaks ASIO Link. It doesn’t happen with other audio applications (for example VCV Rack) so I suspect something strange happens between SC and ASIO Link Pro.

As you can see in the GIF below the channel never returns to 0 on the side of Bitwif ASIO server. If I send a sine wave with constant amplitude the channel becomes, and remains, red (completely saturated).

s.options.device_("ASIO : ASIO Link Pro");

SynthDef(\trigtest2, {arg freq, amp, dur=1, t_trig;
	var signal, env;
	env = EnvGen.ar(Env.perc(0.01, dur, amp), t_trig, doneAction:0);
	signal = SinOsc.ar(freq) * env;
	Out.ar(3, signal);

a = Synth(\trigtest2, [\freq, 333, \amp, 1, \t_trig, 1]);

Again, this doesn’t happen on channel 0 and 1, and doesn’t happen when the same setup is used with other audio applications.
Am I using the other channels in SC the wrong way?

What’s not clear to me is why channel 4 in the scsynth.exe window does go down to 0 (so, ASIO Link is getting silence from the server) but it’s different in bitwig.


Exactly @jamshark70 this is what I’m wondering too… and everything works fine if I use chanells 0 and 1.

My point was, if scsynth is providing 0s for silence and ASIO Link is passing nonzero values to Bitwig – I do hear you that it isn’t happening with other software but… the point at which silence is becoming non-silence appears to be outside of SC.

Btw what is the sample rate that scsynth is reporting when booting the server? That’s not visible in your GIF.


the sample rate is 44100, which is the same as the sample rate reported by my Focusrite ASIO driver (that’s being used by ASIO Pro Link).

Requested devices:
  Out (matching device found):
  - ASIO : ASIO Link Pro

Booting with:
  Out: ASIO : ASIO Link Pro
  Sample rate: 44100.000
  Latency (in/out): 0.012 / 0.012 sec
SC_AudioDriver: sample rate = 44100.000000, driver's block size = 64
SuperCollider 3 server ready.
Requested notification messages from server 'localhost'
localhost: server process's maxLogins (1) matches with my options.
localhost: keeping clientID (0) as confirmed by server process.
Shared memory server interface initialized
server 'localhost' disconnected shared memory interface
Shared memory server interface initialized

Asio Link Pro is still a mistery to me. Now everything seems to work fine without any apparent change…

If anyone knows what the Route OUT to IN is supposed to do please let me know. I turned it on/off several times both from the Asio Link Pro Tool and the SC client, and nothing apparently happens. I went back to the initial configuration in the end… and now the buffer goes to zero also on the server (Bitwig) side.