[sdiy] Craig Anderton's Multiple Identity Filter

[Olivier Gillet]

> How do you cross-fade between two filters in series and the same
> in parallel ? If series is a(b(x)) and parallel is a(x) + b(x),

Not true crossfading but something like this:

a(k b(x) + (1-k) x) + (1-k) b(x)

k = 0: a(x) + b(x)
k = 1: a(b(x))


Or two independent crossfaders - one as a final stage that crossfades
between a(x) and b(x) ; and one at the input of a that crossfades
between a and x.