Bi-amp question

Ok... I have recently purchased a set of psb synchrony ones and a NAD M3 amp(180 wpc)... if were to add another amp, say a Rotel RB-1170(130 wpc) for bi-amping... which way would make the most sense to wire them up? NAD for the Highs and Rotel for the Lows? or vice versa???
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looks like what you are wanting to try out is "dual amping" your speakers 'cuz you will continue to use the factory provided built-in x-overs.
This might or might not be beneficial, as others have already stated.
The highest probability of success (if there is any for your situation) will occur when you have 2 identical stereo amps OR 4 identical mono amps 'cuz you will not have to worry about amplifier gain, amplifier sensitivity, amplifier sonics, amplifier headroom, amplifier current delivery capability, etc. For any other situation, it's a hit or miss - the difference in the different amplifiers' capability might negate any benefit of dual-amping.
True biamping is more complex that simply dual-amping - the ultra-purist (& IMO the bold) will completely gutt or simply disconnect the entire factory provided x-over & use an external (tube/s.s) xover & the purist will disconnect the bass xover while keeping the mid/tweeter xover & still use an external xover. Usually the external xover is used between the preamp & power amp to avoid using multiple preamps.

DACT has a 10k, 0 to -12 dB in 0.5 dB steps, "fine tuning" attenuator that can tame different amps. Easy enough to add series resistance if required (50K for some tube preamps). Inline with the "stronger" amp after the Y. Another pair of IC's, a small project box (Goldpoint?) and a drill, a knob, 4 female RCAs, hook-up wire and a bit of soldering.

Don't try this with pots.

The concern over "different sounding amps" makes no sense. The drivers powered by the two amps are totally different technology, with sound characteristic differences far greater than that between two amps.

Correction: The "fine" attenuator only comes in single deck mono, so you would need two of them.

With monoblocks, that actually works better with the attenuators close to each amp, in separate enclosures.

Some "pro" amps have adjustable gain built in but it's probably just a cheap pot.

Rodman99999: "Both amps will still remain saddled with reproducing the full signal, from your preamp."

Well...yes and no. Certainly each amp is driven by the full-band signal from the preamp, but each amp doesn't drive the same full-range signal from the preamp. This is because each amp is driving only part of the speaker's crossover. The amp driving a low-frequency end is presented with a load that increases its resistance dramatically as the frequency rises, and each amp driving a high-frequency end is presented with a load that increases its resistance dramatically as the frequency lowers.

Then if one has an amp with great-sounding bass and edgy treble, use it as a bass-end amp, and if one has an amp with great-sounding MR and treble but is a bit wimpy in the bass, use it as a upper-frequency amp.

Of course, the biggest problem with passive biamping with different amps, that of matching the different Voltage gains, still remains if one doesn't already have gain controls on the higher-gain amp.

IMO passive biamping can be rewarding, but it's not for novices unless you don't care if the tonal balance of your speaker systems ends up badly inaccurate.
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