pvsbandp — A band pass filter working in the spectral domain.


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


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


fsig -- output pv stream

fsigin -- input pv stream.

xlowcut, xlowfull, xhighfull, xhighcut -- define a trapezium shape for the band that is passed. 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 yield and exponential shape:

(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-pass filter with a spectral envelope shaped like

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


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

Example 653. Example of the pvsbandp opcode.

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

; 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 pvsbandp.wav -W ;;; for file output any platform

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		pvsbandp	fftin, klowcut, klowfull, khighfull, khighcut ; band pass
abp		pvsynth	fftbp; resynthesis
		out		abp

i 1 0 3

See Also

pvsanal, pvsynth, pvsadsyn, pvsbandr


Author: John ffitch
December 2007