What do you gain from bi-amping Magnepan 1.6s or

I haven't done it myself, but if I understand the theory correctly, the advantage, besides additional power is supposed to be that the one pair of amps that is only producing the mid/treble frequencies can do a better job with lower distortion if it doesn't have to produce bass frequencies. Some also like to do it so that they can use tube amps for mid/treble and solid state for the bottom end.

Thanks guys.

Sufintanil - thanks, this is some very basic info but very enlightening to me as a beginner. I would have thought using 2 amps on each speaker would have more appropriately been called "quad amping"

Roxy54 - Yes, you are probably right but it surprises me that people can justify going to all that added expense for what seems to be not a great increase in sound quality. Then again, maybe there is a great increase.

Some info on the subject: (http://sound.westhost.com/bi-amp.htm)

Having recently tried bi-amping for the first time, with excellent results I must say, I'll take a crack at this.
Although the link Rodman provides is excellent, it is a lot of reading. So here's a beginners explanation. Bi-amping provides one amplifier channel per set of terminals on your speakers. The 1.6 has terminals for high and low frequencies so bi-amping them requires 4 channels of amplification. You could use 4 monoblocs, 2 stereo amps or a single 4 channel amp to get one channel per speaker driver.
Also, you would need to split the output from your preamp to provide an input to each of the channels. In my case, the amps (PS Audio) have a switch on the back to route the input to both channels. Some amps have a line input and output to provide chaining the amps together for bi-amping. Linn and Musical Fidelity are two that come to mind.
I won't address inserting filters as I did not do it that way. I ran each amp full range and let the speakers crossover provide the filtering. Just to be clear on that, your speakers provide filtering (crossover) to ensure only the desired frequencies reach each driver. The crossover is basically 2 filters that keep the drivers from reproducing frequencies they are not intended to produce.
I hope this helps.

You have to match all the amplifiers gain. if the other amp have higher gain than the other amp you will have balance problem, either you're vertical or horizontal bi-amping.