Sfrounds: Njonker has raised the most important question for
you to answer. Are your speakers truely biamp-capable to
begin with? Check with the dealer/manufacturer. The speaker inputs MUST allow you to connect to (typically) the
woofer independently, and the midrange+tweeter units
independently (usually there is a passive crossover inside
the speaker to split between mid and high). If so, then
separate amps can drive the two "halves" of the speaker, each amp delivering a restricted frequency range specific
for that driver(s). This is done by putting an active
crossover device between your preamp and the amps, to "feed"
each amp a limited Hz range. This active device should at
least approximate the crossover frequency/slopes that the
manufacturer originally built into the speakers (i.e., the
original internal division of bass from mid/hi signal). In
my opinion, the resulting "vertical biamping", which uses 2
stereo amps, gives a much more open sonic presentation. The
speaker/amps are less stressed too. And as Sean has nicely
outlined above, you can choose different "styles" of amps
for bass and mid/hi. If the 2 amps have different GAIN, then
your active crossover will need level controls to match the
loudness resulting from the separate amplification. Active
crossovers can be obtained from Bryston, Marchand, and some
other companies. You may want to consider a 3-way crossover
which would do all the above, but also route the lowest Hz
to an active subwoofer, to relieve your main woofers of having to produce the lowest octave; this in a sense would
be tri-amping.
Good luck... it's a lot of work/money but worth it.
