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dzannotti / junox

An emulator of a Roland Juno 60
https://dzannotti.github.io/junox/
GNU General Public License v3.0
23 stars 6 forks source link

Implement Pirkle LPF #15

Closed dzannotti closed 5 years ago

dzannotti commented 5 years ago

The LPF in Pirkle's book seems closer to the Juno's implementation

pendragon-andyh commented 5 years ago

When you do this then can you rename existing one to something like "vcf-moog.js" and use "vcf-diode-ladder.js" for the new version. That will allow us to take a pick-and-mix approach to constructing other instruments.

I like the Moog filter because the maths for calculating the parameters are super easy. It would expect it to take me a couple of elapsed-weeks to work out good mappings for most other designs.

pendragon-andyh commented 5 years ago

I am hoping that the main difference between the implementations is the resonance. With the resonance slider at 10, the actual cutoff frequency apparently Fc to Fc * 0.707 (according to Pirkle's Synth book). This is borne out by the calibration section of the Service Notes.