I'm about 3/4 way done building an active crossover for bi-amping
the 3677's I got from JBL. What I began thinking about is the HF
comp network. Since it ends up being a bypassed voltage divider,
I was trying to figure out what resistor values to use for a given
compensation. If I need ~10dB of relative boost at 20KHz, starting
above say 12KHz, it seems I'd need a divider with 10dB attenuation,
then bypassed for a 3dB point around where I want the boost to
kick in. Two questions. Using 10K ohms as the series resistor,
what value goes to ground? If I'm feeding the output to the high
pass filter, does it need another op-amp buffer between the HF comp
and the HP filter?
Thx, Chris

I haven't decided if you're nuts or you deserve a medal :^).
I posted the question pretty late PST and you still responded same
night in a later time zone. Anyway, I'm not sure I understand the
last comment about generating a shelving response before augmentation.
I'm assuming that what we are attempting to do is produce a filter
that has a mirror response to the published freq. response curves
for the horns. To me, that means I need flat up to ~12K, then
+6dB/octave (or more) on up. Am I missing something?

Thx, Chris

Tweeter output from π passive crossover

Maybe I wasn't clear. What I'm using to divide the frequencies
are 18dB VCVS (Sallen-Key) filter stages. To control horn attenuation,
I'm putting a balance pot circuit between the inputs for
high/low (verses left/right). I was planning on putting the
HF comp between the output of the balance buffer and the input
of the HP filter. But now you're going to make me install spice
or write a perl script to verify what you are saying. Seems to
me that at freqs below 1/(2*Pi*Rs*C) (there's that Pi thing again :^),
the divider will work more like a divider because Xc will be > Rs.
Above that freq, the Xc will be less than Rs, hence provide HF
boost. It looks a lot like the one used in your x-overs. Wonder
where I got the idea. )^:

Rs
acsii art time: --\/\/\/\/\------
|___||_____| |
|| |
C #
# Rp
#
#
|

I got the filter circuits from an old Walter Jung OpAmp Apps book
from when I was in school. Gee, I know the formulas are close,
but I'll have to look them up AGAIN!

Thx, Chris