Will my biamping dreams come true ??

Passively biamping with amplifiers having very different power capabilities creates an additional problem, besides the need to gain match and the possibility of sonic issues due to the amp's having differing sonic characters. You would not be able to utilize most of the power capability of the higher powered amp.

Your Classe amp is rated at 800 watts into the 4 ohm nominal impedance of your speakers. The BAT is rated at 60 watts into 4 ohms. In a properly gain matched passive biamp arrangement both amplifiers have to output identical voltages at any instant of time, in a given channel, corresponding to the full frequency range signal. Therefore you would not be able to raise the volume control high enough to utilize most of the power capability of the Classe amp without clipping the BAT amp, which if clipped would result in severe distortion and possibly even blown tweeters. In effect, you would be converting the 800 watt Classe into perhaps (just guessing) a 100 or 150 watt amp, depending on how much voltage the BAT amp is capable of putting out.

Using an active crossover ahead of the amps would resolve that problem, at least mostly, and would also presumably allow you to gain match. You would still be left with the possibility that sonics may be adversely affected by the different sonic characters of the two amps, particularly at frequencies that are in the crossover region, where both amps would be contributing to the sound that is heard.

I have no particular familiarity with active crossovers, but if you want to go that way models that should be looked into are made by Marchand, Bryston, and Rane.

Regards,
-- Al

With all due respect to Mr. Von Schweikert, he must have been having a bad day when he wrote that. He is wrong in two respects, in the case of passive biamping of a speaker that has been designed to work ok either biamped or single amped (as opposed to the unusual situation of a speaker made up of completely separate elements for the different frequency ranges, that will only work properly when separate amps are used for each element, with an active crossover ahead of them):

1)What has to be matched is gain, not sensitivity. Although several decades ago it was defined differently, sensitivity is defined in modern times as the input voltage required to drive the amp to its rated maximum power. If both amps have a sensitivity of, for example, 1 volt, but one amp puts out 500 watts in response to the 1 volt while the other puts out 100 watts, clearly there is a problem.

2)In a passive biamp arrangement with properly matched gains, a given input voltage will result in the same output voltage from both amps, as it must for proper frequency balance. Therefore (as I indicated in my previous post) if the two amps have very different power capabilities (which he suggests would be a good approach), only a small fraction of the power capability of the higher powered amp can be utilized, without clipping the lower powered amp.

If that is not clear, visualize an ordinary single-amp arrangement. A given input voltage at a treble frequency will result in the same output voltage as would result if that input voltage were at a bass frequency. A passive biamp arrangement needs to behave similarly, or an imbalance between the treble and the bass will result. In both cases, single amp and passive biamp, a given input voltage has to result in the same output voltage regardless of frequency.

And since in a passive biamp configuration there is no filtering ahead of the amps to separate high frequencies from low frequencies, the output voltage of the high frequency amp will include low frequency components that are identical in voltage to those that are present in the output voltage of the low frequency amp, and vice versa.

And it is safe to assume that the maximum output voltage that can be generated by a 60W amp will be far less than can be generated by an 800W amp. Therefore, as I indicated, most of the power capability of the 800W amp cannot be used, in a passive biamp configuration, without clipping the 60W amp.

Regards,
-- Al

To be perfectly accurate, I should add a minor qualification to the following statement in my previous post, which does not affect my conclusions:

... visualize an ordinary single-amp arrangement. A given input voltage at a treble frequency will result in the same output voltage as would result if that input voltage were at a bass frequency. A passive biamp arrangement needs to behave similarly, or an imbalance between the treble and the bass will result. In both cases, single amp and passive biamp, a given input voltage has to result in the same output voltage regardless of frequency.

In saying this, I am ignoring small voltage differences that may occur as a result of interaction between amplifier output impedance and variations of speaker impedance as a function of frequency, in the case of tube amps having low damping factor/high output impedance.

Regards,
-- Al