I'm trying to roughly replicate the sound of the per-stereo-channel 3 band equaliser conttols of an old Citronic Pro-8 / Pro-10 DJ mixer. If I'm correct had a fairly steep curve so bass and treble controls didn't affect middle frequencies much, and were very effective at cutting bass/treble as required.
As long as the sound is all flat when tone controls are centred and there are no odd peaks /resonances.
What type of filter might it have used? Googling 3 band audio equaliser brings up circuits that I don't think would do it? Technically they all seem to be first order if Im correct? OK I should try it first but in principle something to try next anyway? Second order filters? Or even a half way house of technically easy in analogy circuits?
My mixer wasn't parametric but I guess a single parametric tone control (not thought this out at all mind you) could give the same effect on top of a simple first order set of tone controls.