[Csnd] problem with ntrpol
| Date | 2012-08-30 11:59 |
| From | Stefan Thomas |
| Subject | [Csnd] problem with ntrpol |
| Dear community, I have a problem with the ntrpol-opcode, which does not behave, I've excpected. I want to change the brightness of a wave dependent of the midi keyvelocity. But unfortunately the below quoted example doesn't work: <CsoundSynthesizer> <CsOptions> -odevaudio -Ma </CsOptions> ; ============================================== <CsInstruments> sr = 48000 ksmps = 100 nchnls = 2 0dbfs = 1 instr 1 inote notnum ivel veloc ivelsens = 0.9 iamp ampmidi 0.2 icps cpsmidi ibrightest = 0.2 ibright ntrpol 0.9, ibrightest, ivel*ivelsens igausswave ftgen 0,0, 2^13,20,6,1,ibright aenv linsegr 0, 0.01, 1, 7,0, 0.1, 0 asig poscil iamp*aenv, icps, igausswave outs asig, asig endin </CsInstruments> ; ============================================== <CsScore> f 0 10 </CsScore> </CsoundSynthesizer> |
| Date | 2012-08-30 17:25 |
| From | Jim Aikin |
| Subject | [Csnd] Re: problem with ntrpol |
My suspicion, having tried your instrument, is that ntrpol is working fine.
One difficulty is that you're misinterpreting the output of veloc. If you
use a print statement, you'll see that this gives you the _raw_ MIDI
velocity value (between 0 and 127), not a value between 0 and 1. As a
result, your input to ntrpol's 3rd argument is way out of range.
Another tricky spot may be that you're misunderstanding what GEN 20 does.
It's likely to be a poor choice for a waveform generator, or so it would
appear to me, because it's going to produce a signal that varies between 0
and 1 rather than between -1 and 1.
With suitable values, you may get better results with GEN 11. I had to
fiddle with the numbers a bit, but here's what I came up with. (You'll
observe that I don't much care for ampmidi.)
instr 1
ivel veloc
iamp = 0.07 + (ivel / 250)
icps cpsmidi
iratio = 0.6 + (ivel * 0.003)
iwave ftgen 0, 0, 2^13, 11, 64, 1, iratio
aenv linsegr 0, 0.01, 1, 7, 0, 0.1, 0
asig poscil iamp*aenv, icps, iwave
outs asig, asig
endin
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|
| Date | 2012-08-30 20:39 |
| From | Stefan Thomas |
| Subject | Re: [Csnd] Re: problem with ntrpol |
| Dear Jim, thanks for Your tipps and I think You are right, gen11 sounds better. 2012/8/30 Jim Aikin <midiguru23@sbcglobal.net> My suspicion, having tried your instrument, is that ntrpol is working fine. |