[Csnd] moogvcf with high cutoff
| Date | 2011-07-11 03:46 |
| From | Jim Aikin |
| Subject | [Csnd] moogvcf with high cutoff |
I'm finding that raising the cutoff frequency of moogvcf much above 7kHz
causes it to blow up. (In 5.13 in Win7 64-bit ... and is this floats or
doubles? The manual front page doesn't tell me, and nor does the QuteCsound
About box, so I just plain don't know.)
Here is the offending instrument:
sr = 44100
ksmps = 4
nchnls = 2
0dbfs = 1
instr 1
iSine ftgen 0, 0, 8192, 10, 1
iamp = 0.4
ifreq = 200
asig gbuzz 1, ifreq, 15, 1, 0.9, iSine
ifiltrise = p3 * 0.2
ifiltdecay = p3 * 0.8
kfiltenv linseg 300, ifiltrise, 7000, ifiltdecay, 300
afilt moogvcf asig, kfiltenv, 0
aout linen afilt * iamp, 0.01, p3, 0.1
outs aout, aout
endin
This works fine, but if the peak of the linseg envelope is raised to 7500,
the Console output reports that Csound's amp level has become infinite. And
of course sound output abruptly stops.
If this is user error, I hope someone will spot the problem, as I'm writing
some documentation, and I don't want to mislead people about this
good-sounding filter. I normalized the output of gbuzz to 1, as instructed,
and reduced the resonance of moogvcf to 0 in order to avoid possible
feedback problems within the filter. But still -- boom.
--Jim Aikin
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|
| Date | 2011-07-11 09:31 |
| From | Iain McCurdy |
| Subject | RE: [Csnd] moogvcf with high cutoff |
|
Hi Jim, Using a cosine wave instead of a sine wave with gbuzz eradicates the problem: iCos ftgen 0, 0, 8192, 11, 1 Iain. > Date: Sun, 10 Jul 2011 19:46:00 -0700 > From: midiguru23@sbcglobal.net > To: csound@lists.bath.ac.uk > Subject: [Csnd] moogvcf with high cutoff > > I'm finding that raising the cutoff frequency of moogvcf much above 7kHz > causes it to blow up. (In 5.13 in Win7 64-bit ... and is this floats or > doubles? The manual front page doesn't tell me, and nor does the QuteCsound > About box, so I just plain don't know.) > > Here is the offending instrument: > > sr = 44100 > ksmps = 4 > nchnls = 2 > 0dbfs = 1 > > instr 1 > iSine ftgen 0, 0, 8192, 10, 1 > iamp = 0.4 > ifreq = 200 > asig gbuzz 1, ifreq, 15, 1, 0.9, iSine > ifiltrise = p3 * 0.2 > ifiltdecay = p3 * 0.8 > kfiltenv linseg 300, ifiltrise, 7000, ifiltdecay, 300 > afilt moogvcf asig, kfiltenv, 0 > aout linen afilt * iamp, 0.01, p3, 0.1 > outs aout, aout > endin > > This works fine, but if the peak of the linseg envelope is raised to 7500, > the Console output reports that Csound's amp level has become infinite. And > of course sound output abruptly stops. > > If this is user error, I hope someone will spot the problem, as I'm writing > some documentation, and I don't want to mislead people about this > good-sounding filter. I normalized the output of gbuzz to 1, as instructed, > and reduced the resonance of moogvcf to 0 in order to avoid possible > feedback problems within the filter. But still -- boom. > > --Jim Aikin > > > -- > View this message in context: http://csound.1045644.n5.nabble.com/moogvcf-with-high-cutoff-tp4573436p4573436.html > Sent from the Csound - General mailing list archive at Nabble.com. > > > Send bugs reports to the Sourceforge bug tracker > https://sourceforge.net/tracker/?group_id=81968&atid=564599 > Discussions of bugs and features can be posted here > To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe csound" > |
| Date | 2011-07-11 17:04 |
| From | Jim Aikin |
| Subject | [Csnd] RE: moogvcf with high cutoff |
Thanks, Iain. I should have read the manual page for gbuzz more carefully.
It's odd that a user error with gbuzz would appear to be a bug in a
different opcode -- gbuzz seemed to be working with the other filters I
tried, but not with moogvcf.
--
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