Ian Bell wrote:

I'm sure there are chips that can take an input from the PCB and
drive a second pair of outputs to the same spec as the existing
outputs - but what ones would be suitable? Those low noise mosfet
741-thingies?

NE5532 would be my choice.

Cheers.


Very difficult to design a filter that changes amplitude with
frequency without affecting phase. Laws of physics type stuff.

Oh well - I was hoping there might be some clever chippery that could do
that sort of thing.


How much scope is there for being able to tailer the slope of the
filter, and make the slope selectable?

No problem provided steps of about 6dB/octave are acceptable.

I dare say - I want to be able to match the slope to whatever response I get
out of the upper bass / mid speakers.


Can a subsonic shelf be incorporated?

No problem, in fact hard not to do this.

Bypass is easy too.

Good-o.


--
Wally
www.artbywally.com
www.wally.myby.co.uk/music