Thanks!
byoc wrote:
I can't tell you exactly because I've never put it on a spectrum analyzer and it also varies slightly depending on the width of the Q. The midrange control is a Wein bridge network that should have a range of about 250Hz to 5KHz, with approx. 1KHz being at noon, and that sounds about right to my ear. This is in medium Q mode. Changing the Q will shift the center frequency slightly. This is because the Q does not get wider or narrower symmetrically. It changes width by reducing the bass range or increasing the bass range (changing the capacitance of C24). So your center freq will be able to go a little lower in wide mode, but not quite as high. And inversely, your center freq will be able to go a little higher in narrow mode, but not quite as low.
FYI, if you want to shift the range higher, make C24/C27 smaller. If you want to shift the range lower, make C24/C27 larger.