Hi Esa

the usage of an allpass-filter for stereo spreading causes a not mono
compatible signal (sound will be unhearable in kitchen radio and
AM-radio and will cause failures when pressing vinyl).

Florian

esa kotala wrote:

> Applying an all pass filter to the other channel might be more attractive
> choice since you do not have to subject the sound to the limited bandwidth
> of the BBD module. All pass filters have 90 degrees of phase shift at the
> cutoff frequency -- the largest possible expansion. Modulating the point
> could provide an interesting stereo effect