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move code outside of svf environment
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@@ -22,6 +22,7 @@ | |
| // * [Mth-Octave Filter-Banks](#mth-octave-filter-banks) | ||
| // * [Arbitrary-Crossover Filter-Banks and Spectrum Analyzers](#arbitrary-crossover-filter-banks-and-spectrum-analyzers) | ||
| // * [State Variable Filters (SVF)](#state-variable-filters) | ||
| // * [Topology-Preserving Transform Filters](#topology-preserving-transform-filters) | ||
| // * [Linkwitz-Riley 4th-order 2-way, 3-way, and 4-way crossovers](#linkwitz-riley-4th-order-2-way-3-way-and-4-way-crossovers) | ||
| // * [Standardized Filters](#standardized-filters) | ||
| // * [Averaging Functions](#averaging-functions) | ||
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@@ -2633,10 +2634,8 @@ with { | |
| //======================================================================================== | ||
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| //-----------------`(fi.)svf`---------------------- | ||
| // An environment with `lp`, `bp`, `hp`, `notch`, `peak`, `ap`, `bell`, `ls`, `hs`, `morph` SVF based filters. | ||
| // All filters have `freq` and `Q` parameters. The `bell`, `ls`, `hs` ones also have a `gain` third parameter. | ||
| // The `morph` filter has a `blend` third parameter [0..2] continuous, where 0 is `lp`, 1 is `bp`, and | ||
| // 2 is `hp`. This allows seamless blending between those three filter types. | ||
| // An environment with `lp`, `bp`, `hp`, `notch`, `peak`, `ap`, `bell`, `ls`, `hs` SVF based filters. | ||
| // All filters have `freq` and `Q` parameters, the `bell`, `ls`, `hs` ones also have a `gain` third parameter. | ||
| // | ||
| // #### Usage | ||
| // | ||
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@@ -2706,34 +2705,87 @@ svf = environment { | |
| bell(f,q,g) = svf(6, f, q, g); | ||
| ls(f,q,g) = svf(7, f, q, g); | ||
| hs(f,q,g) = svf(8, f, q, g); | ||
| morph(f,q,b) = lpw * lpc , bpw * bpc , hpw * hpc :> _ | ||
| }; | ||
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| //-----------------`(fi.)svf_morph`---------------------- | ||
| // A SVF-based filter than can smoothly morph between being lowpass, bandpass, and highpass. | ||
| // | ||
| // #### Usage | ||
| // | ||
| // ``` | ||
| // _ : svf_morph(freq, Q, blend) : _ | ||
| // ``` | ||
| // | ||
| // Where: | ||
| // | ||
| // * `freq`: cut frequency | ||
| // * `Q`: quality factor | ||
| // * `blend`: [0..2] continuous, where 0 is `lowpass`, 1 is `bandpass`, and 2 is `highpass` | ||
| // | ||
| //--------------------------------------------------- | ||
| declare svf_morph author "Dario Sanfilippo"; | ||
| declare svf_morph copyright "Copyright (C) 2023 Dario Sanfilippo <[email protected]>"; | ||
| declare svf_morph license "MIT-style STK-4.3 license"; | ||
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| svf_morph(f,q,b) = lpw * lpc , bpw * bpc , hpw * hpc :> _ | ||
| with { | ||
| // calculate weights | ||
| lpw = max(0, 1 - b); | ||
| bpw = min(1, b) - hpw; | ||
| hpw = max(0, b - 1); | ||
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| lpc = svf.lp(f, q); | ||
| // shift the phase of the BP by 90deg at `cf` with a one-pole allpass to make it match the other filters' phases | ||
| bpc = svf.bp(f, q) : AP1(f); | ||
| // invert the sign of the HP output to make its phase match the LP's phase perfectly | ||
| hpc = -1 * svf.hp(f, q); | ||
| }; | ||
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| //==================Topology-preserving Transform Filters====================== | ||
| // | ||
| // Topology-preserving transform (TPT) filters. These are useful when the | ||
| // frequency is modulating quickly. | ||
| // | ||
| // #### Reference | ||
| // Zavalishin, Vadim. "The art of VA filter design." Native Instruments, Berlin, Germany (2012). | ||
| //============================================================================= | ||
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| //-----------------`(fi.)onePoleTPT`------------------------- | ||
| // One-pole topology-preserving transform (TPT). The three | ||
| // outputs are the lowpass, highpass, and allpass signals. | ||
| // | ||
| // #### Usage | ||
| // | ||
| // ``` | ||
| // _ : onePoleTPT(freq) : si.bus(3) | ||
| // ``` | ||
| // | ||
| // Where: | ||
| // | ||
| // * `freq`: cut frequency | ||
| // | ||
| //----------------------------------------------------------- | ||
| declare onePoleTPT author "Dario Sanfilippo"; | ||
| declare onePoleTPT copyright "Copyright (C) 2023 Dario Sanfilippo <[email protected]>"; | ||
| declare onePoleTPT license "MIT-style STK-4.3 license"; | ||
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| onePoleTPT(cf, x) = loop ~ _ : ! , si.bus(3) | ||
| with { | ||
| g = tan(cf * ma.PI * ma.T); | ||
| G = g / (1.0 + g); | ||
| loop(s) = v + lp , lp , hp , ap | ||
| with { | ||
| onePoleTPT(cf, x) = loop ~ _ : ! , si.bus(3) | ||
| with { | ||
| g = tan(cf * ma.PI * ma.T); | ||
| G = g / (1.0 + g); | ||
| loop(s) = v + lp , lp , hp , ap | ||
| with { | ||
| v = (x - s) * G; | ||
| lp = v + s; | ||
| hp = x - lp; | ||
| ap = lp - hp; | ||
| }; | ||
| }; | ||
| AP1(cf, x) = onePoleTPT(cf, x) : ! , ! , _; | ||
| // calculate weights | ||
| lpw = max(0, 1 - b); | ||
| bpw = min(1, b) - hpw; | ||
| hpw = max(0, b - 1); | ||
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| lpc = svf.lp(1000, q); | ||
| // shift the phase of the BP by 90deg at `cf` with a one-pole allpass to make it match the other filters' phases | ||
| bpc = svf.bp(1000, q) : AP1(1000); | ||
| // invert the sign of the HP output to make its phase match the LP's phase perfectly | ||
| hpc = -1 * svf.hp(1000, q); | ||
| v = (x - s) * G; | ||
| lp = v + s; | ||
| hp = x - lp; | ||
| ap = lp - hp; | ||
| }; | ||
| }; | ||
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| AP1(cf, x) = onePoleTPT(cf, x) : ! , ! , _; | ||
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| //===========Linkwitz-Riley 4th-order 2-way, 3-way, and 4-way crossovers===== | ||
| // | ||
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