[Csnd] Possible bug with wgbow
| Date | 2011-09-18 03:37 |
| From | "Colman O'Reilly" |
| Subject | [Csnd] Possible bug with wgbow |
| Hi all - I wanted to report a possible bug with the "wgbow" opcode. It appears as if it the frequency output is inconsistent with the "actual" frequency. The deviation is most noticeable at higher frequencies while being relatively accurate at lower values. I prepared an example that should illustrate this audibly.
As always, I could be misunderstanding how this particular opcode should be used, and if so any help would be greatly appreciated. Thank you much! Colman <CsoundSynthesizer> <CsOptions> </CsOptions> <CsInstruments> sr = 44100 kr = 4410 ksmps = 10 nchnls = 2 0dbfs = 1 instr 1 aout oscil .8, cpsmidinn(p4), 1 outs aout, aout endin instr 2 aout wgbow .8, cpsmidinn(p4), 3.0, 0.127326, 6.12723, 0, 1 outs aout, aout endin </CsInstruments> <CsScore> f1 0 16384 10 1 i1 0 1.9 65 i2 2 1.9 65 s i1 0 1.9 80 i2 2 1.9 80 s i1 0 1.9 100 i2 2 1.9 100 s i1 0 1.9 105 i2 2 1.9 105 </CsScore> </CsoundSynthesizer> |
| Date | 2011-09-18 08:08 |
| From | Victor Lazzarini |
| Subject | Re: [Csnd] Possible bug with wgbow |
| Well this I think is a deficiency in the original design. You can say it's a bug, but I think it's in the original algorithm. I am saying this without looking at the code, but as far as I understand there is no fractional delay filter in the waveguide used, so there will be a tuning problem at high frequencies. Victor On 18 Sep 2011, at 03:37, Colman O'Reilly wrote: Hi all - Dr Victor Lazzarini Senior Lecturer Dept. of Music NUI Maynooth Ireland tel.: +353 1 708 3545 Victor dot Lazzarini AT nuim dot ie |
| Date | 2011-09-18 11:18 |
| From | jpff@cs.bath.ac.uk |
| Subject | Re: [Csnd] Possible bug with wgbow |
Not looked at the code but those are the symptoms of delayline quantisation. This code is from Cook's stk I think, and that claims fraction delaylines. It os possible that I transcribed it wrong. ==John > Well this I think is a deficiency in the original design. You can say > it's a bug, but I think it's in the original algorithm. I am saying > this without looking at the code, but as far as I understand there is > no fractional delay filter in the waveguide used, so there will be a > tuning problem at high frequencies. > > Victor > On 18 Sep 2011, at 03:37, Colman O'Reilly wrote: > >> Hi all - >> >> I wanted to report a possible bug with the "wgbow" opcode. It >> appears as if it the frequency output is inconsistent with the >> "actual" frequency. The deviation is most noticeable at higher >> frequencies while being relatively accurate at lower values. I >> prepared an example that should illustrate this audibly. >> >> As always, I could be misunderstanding how this particular opcode >> should be used, and if so any help would be greatly appreciated. >> Thank you much! >> Colman >> >> >> >> >> |
| Date | 2011-09-18 20:13 |
| From | "Colman O'Reilly" |
| Subject | Re: [Csnd] Possible bug with wgbow |
| My thanks to you both. Nice to know that it wasn't just how I was handling things. Best, Colman
On Sun, Sep 18, 2011 at 6:18 AM, <jpff@cs.bath.ac.uk> wrote: Not looked at the code but those are the symptoms of delayline Colman O'Reilly | colman@csoundforlive.com | www.colmanoreilly.com
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