Hope one of those other ideas will be a 2-way electronic crossover with adjustable gain, frequency and phase -- maybe even a couple of different slopes? :-)
-- Jim
Here's the thing that always stops me when I look at a fully-adjustable crossover:
Starting point is a first- or second-order Sallen and Key circuit with cathode followers. Two dual triodes, just like Foreplay or Seduction; possibly another tube for shunt-regulated supply voltage. With no adjustments, it would make a reasonable kit. This is basically what Doc B uses in the Big Rig (I think there are four of them).
adjustable gain: high-pass, low-pass, left and right, that's 4 knobs. For uncompromised filter accuracy, they will need buffers - two more dual triodes.
Adjustable frequency: as above, but each of them is a dual pot. You can't cover any more than an octave that way, so there's a range switch for each as well. That's eight more knobs, total 12.
Phase: Forget it, the only useful way to do this is to implement a variable time delay on each output, which is easy with digital and ridiculous with analog.
So, even without phase you have 12 knobs and at least five tubes. Now think what a b*&^%h it is to wire up the three knobs on a Foreplay or Stereomour. Think about upgrading 4 mono pots plus 4 stereo pots plus four rotary switches. Think about the cost of all those premium pots and switches...
