Resonancne filter

Questions
1

Hello,
I’m trying to make a little resonant filter for producing a kind of high sweep (such as in this file : 09.wav (at 1"", 5", 7")) or more long-lasting effect.

And I find it really difficult with Resonz and Ringz, that I find hard to master in terms of amplitude of the output. The base sounds are usually sinwaves with some distortion and noise(*). Resonz keeps having a really weak output. Ringz, can be way too strong when its resonance frequency matches the one of the base signal or really weak when moving away from that freq.

These are my filters:
Resonz:

rq=effect.neg.lincurve(-1,0,0.0001,1,8,\minmax);
sig=Resonz.ar(orig,freq,rq,1/rq.pow(0.75);
sig=sig*1.5; // add 1.5 to keep level-equivalence between orig signal and filtered one

Ringz

sig=Ringz.ar(orig,freq,effect);

Are there other options for more-controllable resonant filters in supercollider ?

Thanks,

(*)My base sound:

rq=noise.linlin(0,1,0.0001,1,\minmax);
sig = SinOsc.ar(freqd).pow(form.linexp(0,1,1,20,nil));
snoise=Resonz.ar(PinkNoise.ar(1),freqd,rq,2/rq.pow(0.75));
sig=XFade2.ar(sig,snoise,noise.linlin(0,1,-1,1));
2

I think you want to try different source and different filters. A sine wave doesn’t have harmonics so there is nothing to resonate. So, try a low frequency saw or square wave. Also, I would try out the MoogFF and RLPF or RHPF for sweeps. Resonant lowpass and highpass filters tend to give the sweepy vibe I think you want, better than bandpass, though they all have their charm. The last thing is with high, self-oscillating resonance, you could just use noise as the source, and you basically get a noisy sine-wavish sound.

2 Likes
3

That’s a very good point. Filters are all about the differences of gain changes between different frequency areas. A sine wave contains only one frequency, so there is no way to detect any differences between frequency areas. Hence sinewave → any filter is nothing more than a more confusing, harder-to-use volume control – that is, pretty much always a conceptual error.

It’s hard in general to control the amplitude of resonant filters – if the frequency response amplifies some region (RLPF, RHPF, Ringz do), then strong energy at the resonant frequency will cause a volume spike. You could try a Limiter before the envelope generator.

hjh