[sdiy] Filter frequency cutoff with linear response?

[Olivier Gillet]

> The (linear) filter FM discussion is interesting though. A few
> hardwired synths have the possibility to modulate the VCF in the audio
> range with VCOs (Prophet poly-mod style). This is an important way of
> expanding the VCO-VCF-VCA architecture possibilities. But is there any
> of these synths that does this VCF modulation linearly?

The Doepfer Dark Energy does it.

Olivier