Help with bi-amping

Many experts will disagree with that. That's why I said you need to compare 2 100 Watt amps to a 200 watt amp. John Dunlavy believes that the 200 watt amp will win all the time. (SET's not included). A lot of people claim bi-amping is better, but nobody ever wants to do a valid comparison. Two 100 watt amps vs a single 100 is not a valid comparison.

It's sort of an interesting set of tradeoffs comparing the two. The two single amplifiers mean that the high and low frequencies are not intermodulating, which will produce a better sound. This is the opinion I have seen most often from "experts." The single amplifier on the other hand will better divy up the power between the upper and lower frequencies, which will probably let you drive the speakers to a higher SPL. There is also a consideration in that the quality of components used by manufacturers tends to improve with the power of the amplifier, so I don't think that a real world comparison of two 100 watt amplifiers to 1 200 watt amplifier would be an apples to apples comparison.

If that wasn't too clear, when you have two amplifiers connected independently you run out of steam whenever either one reaches it's power limit. On my system the passive crossover crosses over at about 120 Hz. I have seen 240-340 Hz mentioned as the point at which most music contains an equal amount of energy above and below. I can't confirm this, but it seems about right, and for the purposes of this discussion, the exact point really doesn't matter, just that it exists.

Putting these two things together, I think I would run out of power and start clipping on the top end before I ran out of power on the bottom end. Of course, the approach I used is to have more power available on both the top and bottom ends than my speakers can handle, so it really doesn't matter. :-)

Another factor to consider is that with the passive bi-amp system, you are well on the road to having active bi-amping and I have never seen anyone try to claim active bi-amping wasn't better with two 100 watt amps than a single 200 watt amp since this argument would ultimately reduce to the contention that passive crosovers are superior to active crossovers which would be a pretty tough proposition to sell. That is, assuming of course, that the amplifiers used were of the same quality.

Regards,
Greg

I find this thread interesting because Martin Logan has quite a bit of information claiming that the benifits of an active crossover are far more than outweighed by the negative aspects of adding another component into the signal path. It is also interesting that they incorporate a crossover in their Statement speaker system that is also available for the CLS2z's.

pmwoodward - Could you provide a link to the information from Martin Logan? All I could find on their web site was the following paragraph under the ESL Tech technology brief.

"Common low and high pass filter crossovers and the inherent problem of crossing over at higher frequencies produce phase shift and amplitude fluctuation problems when the music signal is recombined. This is because high frequency signals have shorter wavelengths, and changing the distance from the sound source to the ear can present a 180 degree phase shift, and this translates as silence to the human ear".

First, I believe that this statement refers to passive crossovers, not active crossovers. As you noted they do state that they incorporate a crossover in their ESL speakers. One way or the other the thrust of what I saw on their web site seemed to be that no crossover was better than a crossover, not that a passive crossover is better than an active crossover.

That's probably true, but I don't know enough about their technology to comment one way or another. Since we are discussing bi-amping and you can't bi-amp without a crossover of some sort, passive or active, I don't think it applies to this particular discussion thread.

Regards,
Greg

I have an idea. I want to run my SET amp onto a pair of 96 db, full range speakers which I hand built and because it is bass shy, also want to connect my SONIC FRONTIERS POWER 2 to a pair of SW-1, GERSHMAN subs. The input to both amp will have to use the two amp outputs in my SF-Line 2 preamp. To modulate the volume of the bass section amp, I am thinking about getting a pair of the EVS attenuators.
What I am wondering is if this will sound good or will the integration of the lower and high frequency be choppy sounding. The preamp and both amps will be trying to run both of speakers/subwoofers to their lowest to their highest frequency according to the music. The subwoofer has its own built in crossover, but I wonder what is its cutoff point. Will I be more successful adding a crossover to the subwoofer section? Then if I do this, what can I do about the frequency of the full range speakers? Any feedbacks will be greatly appreciated!

PAUL