pvsbandr

pvsbandr — A band reject filter working in the spectral domain.

Description

Filter the pvoc frames, rejecting bins whose frequency is within a band, and with linear interpolation for transitional bands.

Syntax

fsig pvsbandr fsigin, xlowcut, xlowfull, \
      xhighfull, xhighcut[, ktype]

Performance

fsig -- output pv stream

fsigin -- input pv stream.

xlowcut, xlowfull, xhighfull, xhighcut -- define a trapezium shape for the band that is rejected. The a-rate versions only apply to the sliding case.

ktype -- specifies the shape of the transitional band. If at the default value of zero the shape is as below, with linear transition in amplitude. Other values give an exponential curve


(1 - exp( r*type )) / (1 - exp(type))
      

This includes a linear dB shape when ktype is log(10) or about 2.30.

The opcode performs a band-reject filter with a spectral envelope shaped like


        klowcut                       khighcut
________                                      ______________
        \                                    /
         \                                  /
          \                                /
           \                              /  
            \                            /    
     klowfull\__________________________/ khighfull

Examples

Here is an example of the pvsbandr opcode. It uses the file pvsbandr.csd.

Example 654. Example of the pvsbandr opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
; Audio out   Audio in
-odac    ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o pvsbandr.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 16
nchnls = 1
0dbfs = 1

;; example written by joachim heintz 2009

instr 1
Sfile		=		"fox.wav"
klowcut = 100
klowfull = 200
khighfull = 1900
khighcut = 2000
ain		soundin	Sfile
fftin		pvsanal	ain, 1024, 256, 1024, 1; fft-analysis of the audio-signal
fftbp		pvsbandr	fftin, klowcut, klowfull, khighfull, khighcut ; band reject
abp		pvsynth	fftbp; resynthesis
		out		abp
endin


</CsInstruments>
<CsScore>
i 1 0 3
e
</CsScore>
</CsoundSynthesizer>


See Also

pvsanal, pvsynth, pvsadsyn, pvsbandp

Credits

Author: John ffitch
December 2007