filters.csd

Filters
Jacob Joaquin
October 6, 2010
jacobjoaquin@gmail.com
csoundblog.com

<CsoundSynthesizer>
<CsInstruments>
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1
0dbfs = 1.0

instr 1
    icutoff = p4  ; Cutoff / center frequency

    a1 noise 0.707, 0
    a2 butterlp a1, icutoff

    out a2
endin

instr 2
    icutoff = p4  ; Cutoff / center frequency

    a1 noise 0.707, 0
    a2 butterhp a1, icutoff

    out a2
endin

instr 3
    iwidth = p4  ; Width of band pass, in Hz

    a1 noise 0.4, 0
    a2 butterbp a1, 440, iwidth
    a2 balance a2, a1            ; Make up for lost gain

    out a2
endin

instr 4
    iwidth = p4  ; Width of band reject, in Hz

    a1 noise 0.4, 0
    a2 butterbr a1, 440, iwidth

    out a2
endin

</CsInstruments>
<CsScore>

; Low pass
i 1 0    1 22050
i 1 1.5  . 11025
i 1 3    . 5512
i 1 4.5  . 2756
i 1 6    . 1378
i 1 7.5  . 689
i 1 9    . 344
i 1 10.5 . 172
i 1 12   . 86
i 1 13.5 . 43
i 1 15   . 21

s 18

; High pass
i 2 0    1 21
i 2 1.5  . 43
i 2 3    . 86
i 2 4.5  . 172
i 2 6    . 344
i 2 7.5  . 689
i 2 9    . 1378
i 2 10.5 . 2756
i 2 12   . 5512
i 2 13.5 . 11025
i 2 15   . 22050

s 18

; Band pass
i 3 0    1 880
i 3 1.5  . 440
i 3 3    . 220
i 3 4.5  . 110
i 3 6    . 55
i 3 7.5  . 27
i 3 9    . 13
i 3 10.5 . 6
i 3 12   . 3
i 3 13.5 . 1

s 16

; Band reject
i 4 0    1 1
i 4 1.5  . 3
i 4 3    . 6
i 4 4.5  . 13
i 4 6    . 27
i 4 7.5  . 55
i 4 9    . 110
i 4 10.5 . 220
i 4 12   . 440
i 4 13.5 . 880

</CsScore>
</CsoundSynthesizer>