Passive Crossovers, Two Amplifiers

[davidbosch]

Hello, I am not very experienced in this subject so I would like to request your help. I have a Marantz SR3001 7.1 ch receiver and only two three-way University loudspeakers. The Marantz has a configuration available in which two channels can be used as main stereo channels and two more as stereo channels for another room or something else. Since I only have two speakers, I would like to explore the ways in which I can make use of these two extra amplifiers that are not being in use. So, for example, one way of using them would be, I think, wiring them to two passive subwoofers with a lowpass crossover each one and I believe I would have doubled the power employed in reproducing low frequency sound.

Another way, and this is where I don't know what the outcome would really be... is that I could wire the two extra amplifiers to these passive subwoofers with their own LP crossovers and the two main amplifiers to only the midrange and tweeter of the University loudspeakers (with their current crossovers, which have a low pass and high pass for the midranges and high pass for the tweeters.. obviously).

Would that be some sort of bi amplification? I know it is not the same as using an active crossover before the amplifier and wiring one driver to each amplifier but, my question is: since the crosssovers (first order low pass in the case of the woofer, and first order HP for the midrange and tweeter together) present inductive reactance and capacitive reactance in each case, meaning an increase in the loudspeaker system's impedance as frequency goes up (in the case of the woofer) and as frequency goes down (midrange and tweeter), meaning less current will flow through the speakers, meaning less power will be needed from the amplifier, right? or not at all?

If right, the two amplifiers driving the woofers would only need to feed the necessary power for the frequency spectrum the woofers are handling, and the same for the two amplifiers driving the midrange & tweeters together. Please, do correct me, for I am not sure about this.

[nac134]

What you want to do is use the amp in 7 channel stereo mode. That will yield 3 identical left signals, and 3 identical right signals. The best possible way would then be one to the tweeter, one to the midwoofer, and one to the subwoofer, or a tri-amp stereo setup. You could also use the bass management to choke off the deep bass from the midwoofers for more volume. Keep in mind that it might be difficult to achieve good sound with a passive crossover on subwoofers. I have an electronic crossover I would sell for 50 bucks, but you would have to pay shipping.