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Iain is right on.
I use port or portk for amplitude smoothing
routinely.
Art Hunkins
----- Original Message -----
Sent: Thursday, July 02, 2009 12:05
PM
Subject: [Csnd] RE: Smoothing continuous
midi data
Hi Charles you are experiencing 7-bit quantization (zipper)
noise. You need to apply some sort of 'lag' or portamento to the variable in
order to smooth changes between values. I use portk. Don't use too high a
value for portamento time or you will get a sluggish response.
Here's an
example:
<CsoundSynthesizer>
<CsOptions>
-M0
-odac -b100
-B256
</CsOptions>
<CsInstruments>
sr
= 44100
ksmps =
10
nchnls =
2
0dbfs =
1
gisine ftgen 0,0,1024,10,1
instr 1
kamp
ctrl7 1,1,0,1
;PORTAMENTO TIME
iporttime = 0.05
;kporttime QUICKLY
RAMPS UP TO DESIRED PORTAMENTO TIME VALUE
kporttime linseg
0,0.01,iporttime,1,iporttime
;APPLY PORTAMENTO
kamp portk kamp,
kporttime
a1 oscili kamp, 400, gisine
outs
a1,a1
endin
</CsInstruments>
<CsScore>
i 1 0 3600 ;i1, A LONG
NOTE
</CsScore>
</CsoundSynthesizer>
>
Date: Thu, 2 Jul 2009 08:57:48 -0500
> From: chasgran@gmail.com
>
To: csound@lists.bath.ac.uk
> Subject: [Csnd] Smoothing continuous midi
data
>
> If I hold a note on this test instrument and I move the
volume slider
> quickly I get pronounced crackling, this is less
noticeable when I
> move the slider more slowly.
> On my XP PC
with ASIO drivers this goes away when I set the sampling
> rate to
88200. In the lower sampling rate, 44100, is there some kind
> of
stepping that is happening?
> On my IMAC the crackling doesn't seem to
improve much with the sampling rate.
>
> -Charles
>
> <CsoundSynthesizer>
> <CsOptions>
> -M0 -odac
-b100 -B256
> </CsOptions>
>
>
<CsInstruments>
> sr = 88200
> kr = 8820
> ksmps =
10
> nchnls = 1
>
> initc7 1,7,.5
>
> instr
1
> ifqc cpsmidi
> iamp ampmidi 5000
> kenv linenr iamp,
.01, .1, .01 ;gain
> kamp ctrl7 1, 7, 0, 1
> a1 oscili kenv*kamp,
ifqc, 1
> out a1
> endin
> </CsInstruments>
>
> <CsScore>
> ; Sine wave
> f1 0 16384 10 1
>
i1 0 3600
> </CsScore>
> </CsoundSynthesizer>
>
>
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