> Nobody is mentioning the most interesting use for a voltage
> controllable delay with very short delay times - analog physical
> modelling. To do 'tuned resonator' types of blown pipe emulations one
> needs precise voltage control with sub millisecond resolution, along
> with voltage control of feedback. If it has to be digital to achieve
> that much control, so be it - but it will take a purpose-built
> design, not a hacked up pedal.
I thoght about building something like that in the past, but there was
always one think that kept me from really doing it:
The BBD line can be "played in tune" if you have an exponential
clock VCO. But for physical modelling, you need a filter in the
feedback path, don't you ? And every filter has some extra phase shift
(i.e. frequency dependend delay), so it will make the model go out of tune.
In a fully digital implementation you can correct this, but in analogue ?
JH.