Author |
Message |
ullyssen
Joined: Sep 22, 2017 Posts: 4 Location: everywhere
|
Posted: Fri Sep 22, 2017 4:57 am Post subject:
Extreme level peak from SqrOsc oscillator |
|
|
Hi!
I need some strange artifact to be removed from ChucK output.
I created the following code: simple function to control square oscillator:
Code: |
fun void sqrG(int tone, int time, int silence)
{
SqrOsc o => ADSR e => dac;
tone => o.freq;
e.set(0::samp,2::samp,0.5,1::samp);
e.keyOn();
time::ms => now;
e.keyOff();
silence::ms => now;
}
|
Every time this function is executed, resulting square signal contains extreme level peak right at the beginning, as shown on this screenshot from Audition editor:
Interesting is that all other oscillator types (SinOsc, TriOsc, SawOsc) don't produce this artifact. |
|
Back to top
|
|
|
gabbagabi
Joined: Nov 29, 2008 Posts: 651 Location: Berlin by n8
Audio files: 23
|
Posted: Fri Sep 22, 2017 8:17 am Post subject:
|
|
|
hi,
what ur using to measure?
may a soundcard oszilloskope?
if so soundcards often have caps on there inputs that could provoke this behaviour on square waves. |
|
Back to top
|
|
|
ullyssen
Joined: Sep 22, 2017 Posts: 4 Location: everywhere
|
Posted: Fri Sep 22, 2017 9:13 am Post subject:
|
|
|
g.gabba wrote: | hi,
what ur using to measure?
may a soundcard oszilloskope?
if so soundcards often have caps on there inputs that could provoke this behaviour on square waves. |
No, output was directly recorded to WAV file and analysed in Audtion CS6 editor. |
|
Back to top
|
|
|
blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
|
Posted: Fri Sep 22, 2017 9:20 am Post subject:
|
|
|
It looks like the anti-aliasing behaves a bit strange directly after initialization ... it might be easiest to apply some startup envelope to mask the effect ... _________________ Jan
also .. could someone please turn down the thermostat a bit.
|
|
Back to top
|
|
|
ullyssen
Joined: Sep 22, 2017 Posts: 4 Location: everywhere
|
Posted: Fri Sep 22, 2017 9:54 am Post subject:
|
|
|
Blue Hell wrote: | It looks like the anti-aliasing behaves a bit strange directly after initialization ... it might be easiest to apply some startup envelope to mask the effect ... |
Could you provide me with some code example? |
|
Back to top
|
|
|
blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
|
Posted: Fri Sep 22, 2017 9:59 am Post subject:
|
|
|
Sorry, I'm not able to do so ... but I could interpret your image
Maybe Antimon can come up with something? (when he is not too busy preparing for two shows to run ...) _________________ Jan
also .. could someone please turn down the thermostat a bit.
|
|
Back to top
|
|
|
ullyssen
Joined: Sep 22, 2017 Posts: 4 Location: everywhere
|
Posted: Fri Sep 22, 2017 1:09 pm Post subject:
|
|
|
I've changed the code, so
Code: | SqrOsc o => ADSR e => dac; |
became
Code: | SqrOsc o => Dyno limiter1 => ADSR e => Dyno limiter2 => dac; |
and then I've activated both limiter instances.
Yet this peak still emerges. |
|
Back to top
|
|
|
Grumble
Joined: Nov 23, 2015 Posts: 1294 Location: Netherlands
Audio files: 30
|
Posted: Mon Sep 25, 2017 3:09 am Post subject:
|
|
|
What strikes me as strange is that ringing occurs BEFORE a step of the signal as well as AFTER the step.
_________________ my synth |
|
Back to top
|
|
|
blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
|
Posted: Mon Sep 25, 2017 5:15 am Post subject:
|
|
|
Heh, ringing before means that it is not ringing but bandlimiting instead being in effect. _________________ Jan
also .. could someone please turn down the thermostat a bit.
|
|
Back to top
|
|
|
blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
|
Posted: Mon Sep 25, 2017 5:17 am Post subject:
|
|
|
You can think of it being a square wave approximated by sines. _________________ Jan
also .. could someone please turn down the thermostat a bit.
|
|
Back to top
|
|
|
|