Csound Csound-dev Csound-tekno Search About

What is wrong with butterhp?

Date2005-10-11 15:03
FromJan Jacob Hofmann
SubjectWhat is wrong with butterhp?
Dear List,

as I am using the high-pass butterworth-filter for filtering out 
frequencies below 20 hz I do experience a lot of noise. Is this a 
"feature" due to the laws of signal-processing or is something wrong 
with butterhp? I am using Csound 4.23 , ma++' s version.

Best regards,

Jan Jacob



Here is a test orc/sco:

butterhp-test.orc:
   sr = 48000
   kr = 4800
   ksmps = 10
   nchnls = 1


instr 1		; Band pass filter for comparison
	kfreq	line		100, p3, 0
	asig		oscil	30000,kfreq,1
	asig		butterbp	asig, 10520, 21000			; this bp-filter should do more or 
less the same as butterhp below: it works
			out 		asig
endin

instr 2
	kfreq	line		100, p3, 0
	asig		oscil	30000, kfreq,1			; noise is added here
	asig		butterhp	asig,	20
			out 		asig
endin


butterhp-test.sco:
f1	0	32768	10	1
i1 0 29
i2 30 29
e

sound         |         movement          |          object         |   
        space
sonic architecture       |        site: http://www.sonicarchitecture.de
spatial electronic composition     |    2nd order ambisonic music 
  

Date2005-10-11 15:29
FromVictor Lazzarini
SubjectRe: What is wrong with butterhp?
No noise here (on Windows  with csound5 or 4.23).
The sound just fades out.

Victor

At 15:03 11/10/2005, you wrote:
>Dear List,
>
>as I am using the high-pass butterworth-filter for filtering out 
>frequencies below 20 hz I do experience a lot of noise. Is this a 
>"feature" due to the laws of signal-processing or is something wrong with 
>butterhp? I am using Csound 4.23 , ma++' s version.
>
>Best regards,
>
>Jan Jacob
>
>
>
>Here is a test orc/sco:
>
>butterhp-test.orc:
>sr = 48000
>kr = 4800
>ksmps = 10
>nchnls = 1
>
>
>instr 1         ; Band pass filter for comparison
>         kfreq   line            100, p3, 0
>         asig            oscil   30000,kfreq,1
>         asig            butterbp        asig, 10520, 
> 21000                      ; this bp-filter should do more or less the 
> same as butterhp below: it works
>                         out             asig
>endin
>
>instr 2
>         kfreq   line            100, p3, 0
>         asig            oscil   30000, kfreq,1                  ; noise 
> is added here
>         asig            butterhp        asig,   20
>                         out             asig
>endin
>
>
>butterhp-test.sco:
>f1      0       32768   10      1
>i1 0 29
>i2 30 29
>e
>
>sound         |         movement          |         object         | 
>    space
>sonic architecture       |        site: 
>http://www.sonicarchitecture.de
>spatial electronic composition     |    2nd order ambisonic music
>

Victor Lazzarini
Music Technology Laboratory
Music Department
National University of Ireland, Maynooth 

Date2005-10-11 22:56
Frommassimofragala@tiscali.it
SubjectRe: What is wrong with butterhp?
No noise on Windows with csound AV.  Butterworth filter is OK.
I tried this orchestra on mac with Csound 4.23  ma++' s version. There is
a noise.
I think it  is Cound mac problem.

Massimo

>-- Messaggio Originale --
>Reply-To: csound@lists.bath.ac.uk
>To: Csound List 
>From: Jan Jacob Hofmann 
>Date: Tue, 11 Oct 2005 16:03:02 +0200
>Subject: [Csnd] What is wrong with butterhp?
>
>
>Dear List,
>
>as I am using the high-pass butterworth-filter for filtering out 
>frequencies below 20 hz I do experience a lot of noise. Is this a 
>"feature" due to the laws of signal-processing or is something wrong 
>with butterhp? I am using Csound 4.23 , ma++' s version.
>
>Best regards,
>
>Jan Jacob
>
>
>
>Here is a test orc/sco:
>
>butterhp-test.orc:
>   sr = 48000
>   kr = 4800
>   ksmps = 10
>   nchnls = 1
>
>
>instr 1		; Band pass filter for comparison
>	kfreq	line		100, p3, 0
>	asig		oscil	30000,kfreq,1
>	asig		butterbp	asig, 10520, 21000			; this bp-filter should do more or

>less the same as butterhp below: it works
>			out 		asig
>endin
>
>instr 2
>	kfreq	line		100, p3, 0
>	asig		oscil	30000, kfreq,1			; noise is added here
>	asig		butterhp	asig,	20
>			out 		asig
>endin
>
>
>butterhp-test.sco:
>f1	0	32768	10	1
>i1 0 29
>i2 30 29
>e
>
>sound         |         movement          |          object         |  

>        space
>sonic architecture       |        site: http://www.sonicarchitecture.de
>spatial electronic composition     |    2nd order ambisonic music 
>  


__________________________________________________________________
TISCALI ADSL
Solo con Tiscali Adsl navighi senza limiti e telefoni senza canone 
Telecom a partire da 19,95 Euro/mese.
Attivala subito, I PRIMI DUE MESI SONO GRATIS! CLICCA QUI:
http://abbonati.tiscali.it/adsl/sa/1e25flat_tc/


Date2005-10-12 12:39
FromIstvan Varga
SubjectRe: What is wrong with butterhp?
massimofragala@tiscali.it wrote:

> No noise on Windows with csound AV.  Butterworth filter is OK.
> I tried this orchestra on mac with Csound 4.23  ma++' s version. There is
> a noise.
> I think it  is Cound mac problem.

Is it also noisy when using 64 bit floats ?

Date2005-10-12 14:59
FromVictor Lazzarini
SubjectRe: What is wrong with butterhp?
Is there a double-precision version of ma++'s maccsound?

At 12:39 12/10/2005, you wrote:
>massimofragala@tiscali.it wrote:
>
>>No noise on Windows with csound AV.  Butterworth filter is OK.
>>I tried this orchestra on mac with Csound 4.23  ma++' s version. There is
>>a noise.
>>I think it  is Cound mac problem.
>
>Is it also noisy when using 64 bit floats ?
>--
>Send bugs reports to this list.
>To unsubscribe, send email to csound-unsubscribe@lists.bath.ac.uk

Victor Lazzarini
Music Technology Laboratory
Music Department
National University of Ireland, Maynooth