This library contains formula devices that will aid keytracking various renoise native's effects frequency parameters.
To install it, drag&drop the file into renoise. You should get a popup stating that effect presets have been installed. You can access the presets in the preset browser of the formula device (load one, and click on the "init" field to its upper right to see a preset list).
Usage is simple but requires a bit of setup. Let me explain for example for an analog filter - load one to a track or fx line. Then load the corresponding formula device preset, i.e. "TrkAnaFlt" (yeah I like short but ugly names for my presets). Load a keytracker, set to full range, so from "C-0" to "B-9". Point the keytracker to the formula device's "Key" macro. Point the formula device to the analog filter's cutoff.
You should now be able to control the filter cutoff with the keytracker. The formula in between will translate the key to pretty exact pitch. It will first translate the keytracker output to a frequency in hz, then apply a formula on it that will translate it to the slider warping of the effect.
You can also map your pitch bend wheel (when using inside the instrument effects, for example) to the "bend" macro, or automate it otherwise, to get an 12 semitone up/down pitch bend action. Center frequency will always be 0.5.
Supported devices so far:
TrkAnaFlt - "Analog Filter" device
TrkChorusInstr - 3.1 "Chorus" or "Flanger" filters with frequency controls, or via a macro the instrument filters
TrkDigiFlt - "Digital Filter" device
TrkEQ - "EQ 5" and "EQ 10" frequencies
TrkMBSendExciter - "Multiband Send" and "Exciter" transition bands
TrkMixEQMid - "Mixer EQ" Mid Freq
TrkMpRevColor, TrkMpRevLowCut - "Color" and "Low Cut" controls on "mpReverb"
TrkOldComb - the old "Comb Filter" that has a frequency control
TrkOldFilter - the old filter device from pre 3.1, also
Might be I have forgotten some, that also can be controlled via one of the tracker's formula. Of course you can only track within the device's valid range, for example the lowest frequency for the "Analog Filter" device is 40 hz and when you track, transpose or bend a lower frequency the filter will "freeze" at 40 hz. The digital filter in contrary goes down to 20 hz. Other device's ranges are more severly restricted, for example the Mixer EQ mids, which can only be between 400-3400 hz and can't go lower or higher. You get the idea by moving the devices' sliders to their extremes.
If you look at the formula device code, you see some variables:
local fromnote = 0.0
local tonote = 119.0
local noteoffset = 0.0
local bendrange = 12.0
"fromnote" and "tonote" are the numbers for the keytracker's "c-0" and "b-9". If you need to restrict the range of the keytracker, you can adjust these numbers to keep things tuned well. Sorry I have no tool for calculating them yet, but for example "C-1" is "12.0", "C-2" is "24.0", you get the idea.
The "noteoffset" can be used to transpose the whole action, in a number of semitones. Can be negative, and I think it works with fractions as well. The "bendrange" will allow you to tune the range the "Bend" macro will support, also in semitones, 0.5 will always be center.
Feel free to ask questions if you have problems, or ask for upgrades. No, I will not create a formula for your VST xyz, do it yourself.
I have not tested it with renoise versions prior to renoise 3.1
Have Fun! Sorry for me not posting this earlier, but I was busy chasing rabbits in the meantime.
Known Issues so far:
- the analog filter "diode" mode will be out of tune, drifting from the cutoff upwards in frequency when resonance is raised, so is not really suitable for a tuned filterbass - I think I can do nothing about it yet.
- the old shelving filters aren't correctly tracked as the resonance moves with the "Gain" parameter.
- not all trackable controls anyhow related to frequencies supported yet. urge to the renoise team: please disclose the exact formulas for all kinds of devices controls, also delay values or lfo cycles, compressor timings etc. - even if it might seem absurd to keytrack some of them, it might still be interesting to tune them to a certain frequency in other setups. thank you - this lib was made possible by @taktik posting the initial formula these devices are derived from!