Tri-amping speakers - Which amps

The more common solution is to bi-amp. Here you remove the passive xover for the woofer and use your active xover.

Then for the mids/tweeters you leave the xovers intact. This way you need only two amps and balancing becomes that much easier.

Power requirements are radically different for these amps. You are correct woofers suck up tons of watts, so you need a big amp there. For the mids/tweeters it's a totally different story. I'm using a low power chip amp with terrific success. Some people prefer tube amps with their "silky sound" powering the mid/tweeters.

Unless you are in a theater and need the efficency, you lose little with the xovers in the mid/tweeter.

Hope this helps ...

Regards,
Jerry

It is late at night and maybe I am not reading your post well enough, but I can't see the name (and model) of the speakers. Would be a help answering your question.

Richard

Depending on the efficiency of the speakers, the crossover points and slopes used, the type of music being played, etc... this will determine how much power you'll need for each frequency range being amplified. Having said that, i've always found that "more is better", so long as quality isn't compromised in order to obtain the greater quantity.

One thing that should be noted is that system and amplifier efficiency will go up, so you'll be drawing less power from any given amp at any given volume. Most of this is due to limiting the bandwidth that each amp sees, but some of it will be due to getting rid of the "power sucking" passive crossovers too. Those "power sucking" crossovers also "cover up" low level resolution, so expect to hear greater transparency too.

Due to the lower power demands and greater resolution, crossover distortion from the amps may become more apparent to you. In this area, it helps to have amps that run in Class A longer than most commercially produced amps do. This increases signal purity and moves the point that the amp crosses over into Class B operation above the point of average power consumption. The only downside to this is that there is greater heat to deal with.

As was mentioned, it may make things easier for you by using amplifiers from one manufacturer. In doing so, you can have them increase the bias levels to where you want them and gain match all of the channels at one time. Depending on if the amps are new or used, and what the policies of the company are, they may / may not charge for this service to be done. As such, you might want to talk to the service department of the manufacturer's that you are considering using.

You should be aware that there is quite a bit of "fine tuning" that you'll have to do with a system of this nature. If you are someone that wants to maintain a high level of accuracy, you will at least have to take some minor electrical measurements using a multi-meter. If you're not worried about that kind of stuff, you can simply adjust things by ear until they sound "good" to you. I'm primarily talking about gain settings on the electronic crossover that you use, but you can make this as simple or complicated as you would like to carry it.

One more thing. Running multiple amps will require greater electrical resources. Are your AC resources up to the task? If not, factor that into the cost of such an installation too. Sean
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Jerry / Onplane: I would beg to differ as i've yet to hear even a 6 dB crossover ( a simple capacitor in series with the tweeter ) that sounds as good as a "naked" tweeter ( no capacitor ) actively crossed. This not only has to do with removing the capacitor from the high current area of the circuit, but also from the electrical changes that take place prior to the amplification stage.

My Brother made the same assumption that you did here, as he was running his system as you described for quite some time. When i finally got him to try using an antique "Pro Sound" active 3 way that i had laying around, he was flabbergasted at the difference. He couldn't believe he had wasted all those listening sessions with reduced fidelity when even a 30 year old active crossover ( $40 on Ebay ) could have provided so much better results. Bare in mind that this was using cheap plastic Radio Shack 1/4" to RCA adaptors on every cable in and out of the crossover too. Sean
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As Jerry mentioned I have considered bi-amping due to the advantages such as cost, space, & simplicity to name a few. But that would seem to be a compromise. Think I would always wonder if bi-amping was an improvement, wouldn't tri-amping be better. Have not totally discarded the idea however.
Sean, you mentioned most of the things I have had to consider if I go this route. I have thought about Class A or tubes for the tweeters and mids and bipolar amps for the woofer. Obviously you cannot have this with a multi channel amp. With 3 stereo amps you have to consider compatibility issues with the system. I am not totally familiar with an electronic crossover, but as I understand it cannot totally correct for all mismatches between power sources. Any suggestions on actual amps to consider? (I am serious about doing this but don't want to just throw money at it. I like a noticable improvement, and not to quickly reach the diminishing return category.)
In your last section you mentioned 'electrical resources'. Were you talking about available power from my wall socket? If so I think the increased efficiency of tri-amping will allow amps of about 50% the usual power requirements.
The monitors with mids and tweeters are an MTM design with 4 ohm impedance and 90 db sensitivity. The wooofer cabinets have a 10" active driver & 12" passive, 8 ohm and 84 db. The sensitivity of the woofer cabinet is low but the designer has told me that 100 quality watts should do fine.
Any more discussion would be greatly appreciated.