Csound.Air.Filter

Filters

Documentation

Arguemnts are inversed to get most out of curruing. First come parameters and the last one is the signal.

First order filters

lp1 :: Sig -> Sig -> Sig

First order low pass filter (tone in Csound, 6 dB)

lp1 centerFreq asig

hp1 :: Sig -> Sig -> Sig

First order high pass filter (atone in Csound, 6 dB)

hp1 centerFreq asig

Simple filters

lp :: Sig -> Sig -> Sig -> Sig

Low-pass filter.

lp cutoff resonance sig

hp :: Sig -> Sig -> Sig -> Sig

High-pass filter.

hp cutoff resonance sig

bp :: Sig -> Sig -> Sig -> Sig

Band-pass filter.

bp cutoff resonance sig

br :: Sig -> Sig -> Sig -> Sig

Band-reject filter.

br cutoff resonance sig

alp :: Sig -> Sig -> Sig -> Sig

All-pass filter.

alp cutoff resonance sig

bp2 :: Sig -> Sig -> Sig -> Sig

Resonance band pass filter (yet another implementation, it's reson in Csound)

bp2 centerFreq q asig

br2 :: Sig -> Sig -> Sig -> Sig

Resonance band reject filter (yet another implementation, it's areson in Csound)

br2 centerFreq q asig

Butterworth filters

blp :: Sig -> Sig -> Sig

Low-pass filter.

blp cutoff sig

bhp :: Sig -> Sig -> Sig

High-pass filter.

bhp cutoff sig

bbp :: Sig -> Sig -> Sig -> Sig

Band-pass filter.

bbp cutoff bandwidth sig

bbr :: Sig -> Sig -> Sig -> Sig

Band-regect filter.

bbr cutoff bandwidth sig

Filter order

type ResonFilter = Sig -> Sig -> Sig -> Sig

Resonant filter.

f centerFreq q asig

type FlatFilter = Sig -> Sig -> Sig

Filter without a resonance.

f centerFreq q asig

filt :: Int -> ResonFilter -> ResonFilter

Applies a filter n-times. The n is given in the first rgument.

flatFilt :: Int -> FlatFilter -> FlatFilter

Applies a flat filter (without resonance) n-times. The n is given in the first rgument.

toReson :: FlatFilter -> ResonFilter

Makes fake resonant filter from flat filter. The resulting filter just ignores the resonance.

Specific filters

Moog filters

mlp :: Sig -> Sig -> Sig -> Sig

Moog's low-pass filter.

mlp centerFrequency qResonance signal

mlp2 :: Sig -> Sig -> Sig -> Sig

Another implementation of moog low pass filter (it's moogladder in Csound). The arguments have are just like in the mlp filter.

mlp2 centerFreq q asig

mlp3 :: Sig -> Sig -> Sig -> Sig

Mooglowpass filter with 18 dB.

mlp3 centerFreq q asig

lp18 :: Sig -> Sig -> Sig -> Sig -> Sig

Low pass filter 18 dB with built in distortion module.

lp18 distortion centerFreq resonance asig

• distortion's range is 0 to 1
• resonance's range is 0 to 1

ladder :: Sig -> Sig -> Sig -> Sig

Moog ladder filter

ladder centerFreq q asig

Formant filters

formant :: ResonFilter -> [(Sig, Sig)] -> Sig -> Sig

Formant filter.

formant bandPassFilter formants asig

It expects a band pass filter, a list of formants and processed signal. The signal is processed with each filter the result is a sum of all proceessed signals. Formant filters are used to mimic the vocalization of the sound.

singA :: Sig -> Sig

Formant filter that sings an A.

singO :: Sig -> Sig

Formant filter that sings an O.

singE :: Sig -> Sig

Formant filter that sings an E.

singU :: Sig -> Sig

Formant filter that sings an U.

singO2 :: Sig -> Sig

Formant filter that sings an O.

Making the smooth lines

smooth :: Sig -> Sig -> Sig

Produces smooth transitions between values in the signals. The first value defines a duration in seconds for a transition from one value to another in piecewise constant signals.

smooth transTime asig

slide :: Sig -> Sig -> Sig

Makes slides between values in the signals. The first value defines a duration in seconds for a transition from one value to another in piecewise constant signals.

Analog filters

Requires Csound 6.07 or higher

alp1 :: Sig -> Sig -> Sig -> Sig

Analog-like low-pass filter

alpf1 centerFrequency resonance asig

alp2 :: Sig -> Sig -> Sig -> Sig

Analog-like low-pass filter

alpf2 centerFrequency resonance asig

alp3 :: Sig -> Sig -> Sig -> Sig

Analog-like low-pass filter

alpf3 centerFrequency resonanceance asig

alp4 :: Sig -> Sig -> Sig -> (Sig, Sig, Sig, Sig)

Analog-like low-pass filter

alpf4 centerFrequency resonance asig

Analog outputs

• asig1 -- 6dB/oct low-pass response output.
• asig2 -- 12dB/oct low-pass response output.
• asig3 -- 18dB/oct low-pass response output..
• asig4 -- 24dB/oct low-pass response output.

ahp :: Sig -> Sig -> Sig

Analog-like high-pass filter

ahp centerFrequency asig

Zero delay filters

One pole filters

zdf1 :: Sig -> Sig -> (Sig, Sig)

Zero-delay feedback implementation of 1 pole filter.

ouputs low-pass and high-pass signals.

zdf1 centerFreq asig = (alp, ahp)

zlp1 :: Sig -> Sig -> Sig

Zero-delay feedback implementation of 1 pole low-pass filter.

zlp1 centerFreq asig

zhp1 :: Sig -> Sig -> Sig

Zero-delay feedback implementation of 1 pole high-pass filter.

zhp1 centerFreq asig

zap1 :: Sig -> Sig -> Sig

Zero-delay feedback implementation of 1 pole allpass filter.

zap1 centerFreq asig

Two pole filters

zdf2 :: Sig -> Sig -> Sig -> (Sig, Sig, Sig)

zero delay feedback 2 pole filter

zdf2 centerFreq q asig = (alp, abp, ahp)

zlp :: Sig -> Sig -> Sig -> Sig

zero delay feedback 2 pole Low pass filter. Q is unipolar [0, 1]

zlp centerFreq q asig

zhp :: Sig -> Sig -> Sig -> Sig

zero delay feedback 2 pole High pass filter. Q is unipolar [0, 1]

zhp centerFreq q asig

zbp :: Sig -> Sig -> Sig -> Sig

zero delay feedback 2 pole Band pass. Q is unipolar [0, 1]

zbp centerFreq q asig

zubp :: Sig -> Sig -> Sig -> Sig

Unity-gain bandpass (zero delay feedback 2 pole). Q is unipolar [0, 1]

zubp centerFreq q asig

zbr :: Sig -> Sig -> Sig -> Sig

zero delay feedback 2 pole Notch (band reject). Q is unipolar [0, 1]

zbr centerFreq q asig

zap :: Sig -> Sig -> Sig -> Sig

zero delay feedback 2 pole Allpass filter. Q is unipolar [0, 1]

zap centerFreq q asig

zpeak :: Sig -> Sig -> Sig -> Sig

zero delay feedback 2 pole Peak filter. Q is unipolar [0, 1]

zpeak centerFreq q asig

Ladder filter

zladder :: Sig -> Sig -> Sig -> Sig

Zero-delay feedback implementation of 4 pole ladder filter. Q is unipolar [0, 1]

zladder centerFreq q asig

Four poles filters

Eq-filters

Classic analog-like filters

low pass

lpCheb1 :: Sig -> Sig -> Sig

Chebyshev type I low pass filter (with 2 poles).

lpCheb1 centerFreq asig

lpCheb1' :: D -> Sig -> Sig -> Sig

Chebyshev type I low pass filter (with given number of poles, first argument).

lpCheb1' npols centerFreq asig

lpCheb2 :: Sig -> Sig -> Sig

Chebyshev type II low pass filter (with 2 poles).

lpCheb2 centerFreq asig

lpCheb2' :: D -> Sig -> Sig -> Sig

Chebyshev type II low pass filter (with given number of poles, first argument).

lpCheb2' npols centerFreq asig

clp :: Sig -> Sig -> Sig

Butterworth lowpass filter based on clfilt opcode (with 2 poles).

clp centerFreq asig

clp' :: D -> Sig -> Sig -> Sig

Butterworth lowpass filter based on clfilt opcode (with given number of poles, first argument).

clp' npols centerFreq asig

band pass

bpCheb1 :: Sig -> Sig -> Sig -> Sig

bpCheb1' :: D -> Sig -> Sig -> Sig -> Sig

bpCheb2 :: Sig -> Sig -> Sig -> Sig

bpCheb2' :: D -> Sig -> Sig -> Sig -> Sig

cbp :: Sig -> Sig -> Sig -> Sig

cbp' :: D -> Sig -> Sig -> Sig -> Sig

high pass

hpCheb1 :: Sig -> Sig -> Sig

Chebyshev type I high pass filter (with 2 poles).

hpCheb1 centerFreq asig

hpCheb1' :: D -> Sig -> Sig -> Sig

Chebyshev type I high pass filter (with given number of poles, first argument).

hpCheb1' npols centerFreq asig

hpCheb2 :: Sig -> Sig -> Sig

Chebyshev type II high pass filter (with 2 poles).

hpCheb2 centerFreq asig

hpCheb2' :: D -> Sig -> Sig -> Sig

Chebyshev type II high pass filter (with given number of poles, first argument).

hpCheb2' npols centerFreq asig

chp :: Sig -> Sig -> Sig

Butterworth high pass filter based on clfilt opcode (with 2 poles).

chp centerFreq asig

chp' :: D -> Sig -> Sig -> Sig

Butterworth high pass filter based on clfilt opcode (with given number of poles, first argument).

chp' npols centerFreq asig

cheb1 :: Sig -> Sig -> Sig -> Sig

cheb2 :: Sig -> Sig -> Sig -> Sig

vcf :: Sig -> Sig -> Sig -> Sig

cheb1' :: D -> Sig -> Sig -> Sig -> Sig

cheb2' :: D -> Sig -> Sig -> Sig -> Sig

vcf' :: D -> Sig -> Sig -> Sig -> Sig

Named resonant low pass filters

plastic :: Sig -> Sig -> Sig -> Sig

plastic sound

plastic centerFreq q asig

wobble :: Sig -> Sig -> Sig -> Sig

wobble sound

wobble centerFreq q asig

trumpy :: Sig -> Sig -> Sig -> Sig

trumpy sound

trumpy centerFreq q asig

harsh :: Sig -> Sig -> Sig -> Sig

harsh sound

harsh centerFreq q asig

TB303 filter

tbf :: Sig -> Sig -> Sig -> Sig -> Sig

Fixed version of tbfcv filter the first argument is distortion (range [0, 1])

diode :: D -> Sig -> Sig -> Sig -> Sig

Zero-delay feedback implementation of 4 pole diode ladder filter (24 dB/oct) . This filter design was originally used in the EMS VCS3 and was the resonant filter in the Roland TB-303.

• Q is unipolar [0, 1]
• saturation - amount to use for non-linear processing. Values > 1 increase the steepness of the NLP curve.

diode saturation centerFreq q asig

fdiode :: D -> Sig -> Sig -> Sig -> Sig

Faster diode, but lesser quality

fdiode saturation centerFreq q asig

linDiode :: Sig -> Sig -> Sig -> Sig

Linear diode, no saturation involved

linDiode centerFreq q asig

linKorg_lp :: Sig -> Sig -> Sig -> Sig

Linear Korg35 resonant low-pass filter

linKorg_lp centerFreq q asig

linKorg_hp :: Sig -> Sig -> Sig -> Sig

Linear Korg35 resonant high-pass filter

linKorg_hp centerFreq q asig

linKorg_bp :: Sig -> Sig -> Sig -> Sig

korg_lp :: D -> Sig -> Sig -> Sig -> Sig

Korg35 resonant low-pass filter. Q is unipolar [0, 1]

korg_lp saturation centerFreq q asig

korg_hp :: D -> Sig -> Sig -> Sig -> Sig

Korg35 resonant high-pass filter. Q is unipolar [0, 1]

korg_hp saturation centerFreq q asig

korg_bp :: D -> Sig -> Sig -> Sig -> Sig

Korg35 resonant band-pass filter. Q is unipolar [0, 1]

korg_bp saturation centerFreq q asig

klp :: D -> Sig -> Sig -> Sig -> Sig

Alias for korg_lp

khp :: D -> Sig -> Sig -> Sig -> Sig

Alias for korg_hp

kbp :: D -> Sig -> Sig -> Sig -> Sig

Alias for korg_bp

Statevariable filters

slp :: Sig -> Sig -> Sig -> Sig

State variable low-pass filter

shp :: Sig -> Sig -> Sig -> Sig

State variable high-pass filter

sbp :: Sig -> Sig -> Sig -> Sig

State variable band-pass filter

sbr :: Sig -> Sig -> Sig -> Sig

State variable band-reject filter

Multimode filters

multiStatevar :: (Sig, Sig, Sig) -> Sig -> Sig -> Sig -> Sig

multiSvfilter :: (Sig, Sig, Sig) -> Sig -> Sig -> Sig -> Sig