format filter bank/string filter

[Sean Costello]

jhaible wrote:

> What you will want for a "typical" String Ensemble chorus is
> 3 short BBD delay lines and two 3-phase LFOs.
> One LFO is approx. 0.6 Hz, the other one approx. 6 Hz.
> Both LFOs have 3 different outputs with sine waves that are 120 degrees
> apart from each other.
> Each BBD line is modulated by the sum of two LFO outputs:
> BBD1 modulated by LFO1 (0 degree)  + LFO2 (0 degree)
> BBD2 modulated by LFO1 (120 degree)  + LFO2 (120 degree)
> BBD3 modulated by LFO1 (240 degree)  + LFO2 (240 degree)

The String Ensemble chorus described above is typical of such units as
the Solina String Ensemble.  Another method, used in the ARP Omni, is to
have 3 short BBD delay lines, and 3 LFO's - one for each delay line. 
Each LFO can run at two different speeds, slow or fast; the 3 LFO's will
always have different frequencies.  I have heard that the Solina method
produces better results.

One thing I am not certain of is whether the output signal contains the
original "dry" signal, or whether the output is simply the output of the
three delay lines summed together.  The second method would seem to
produce more dramatic results, with lots of yummy "through-zero"
flanging effects.

Sean Costello