Another Sought After Effect (MAX/MSP?)

[Chris Sewell <lunamusic@mac.com>]

Im interested in combining two sources of audio. However, I need to  
split the two signals into two bands of frequency (high and low). I  
also need the crossover point to be sweep-able and the overlap or  
lack thereof (like a notch filter) to also be controlled easily.
I can do this of course in Live using 2 tracks and 2 filters but  
getting the settings right is laborious.
A practical application would using 2 pickups in an acoustic guitar.  
Using the lows of one and the highs of the other. Phase control would  
also be nice.
Would Max/MSP be capable of such device? Is there a simple solution  
Im missing?
Thanks