[sdiy] Vocoder dumb idea of the night

[Tom Arnold]

I've been toying with an idea for a while, basically ever since buying my
PAIA vocoder and wanting more.  Wanted to bounce this idea off some people
and see how insane I was.

After getting Thomas Henry's NE570 application book and playing with the
chip as both an envelope follower and a VCA, I was thinking of coupling
this with my other new found friend the switched capacitor filter and
making a Vocoder.

Have I snapped?

My reason for using the NE570 is, well, they're cheaper then sand and it
keeps my parts count low.
My reason for using a switched capacitor filter is they are also cheaper
then sand and setting the frequency is easy and can be varied also very
easily.  Drawback I see is unless I want to double up filter ICs I'm
stuck with 4th order, which I think ( and I'm hoping to be corrected if
I'm wrong ) that thats only a 24db rolloff which probably isnt steep
enough for a, say, 20band vocoder., which even being cheap as sand will
start adding up.

Still, I think the parts count even at 4 filter ICs per band would be lower
then I could do otherwise.

I actually started toying with this idea while cloning the Ensoniq ISF-1
and playing with the chip on there, but it wasnt nearly as adjustable
as an SFC.

Sanity check please?

-- 
 ------------------------------------------------------------------------
 - Tom Arnold -       When I was small, I was in love,                  - 
 - Sysabend   -       In love with everything.                          -
 - CareTaker  -       And now there's only you...                       - 
 --------------         -- Thomas Dolby, "Cloudburst At Shingle Street" -