Miltiple amps for stereo Matrix 801's

I assume that's a rhetorical question.

Seen it on here so many times that I cringe every time I see "biamp" in a title. It can be done but, in general, if you're asking, you shouldn't. Conversely, I encourage this learning experience for everyone and wish them luck. It's rarely simple and easy except if you're using identical amps, which defeats the purpose to a degree. Unless you're dealing with a really nasty load, like Kappa9's, the only benefit over adequate amplification is reducing the electrical reactance of the woofer affecting the other drivers which, to these ears, has only been theoretical.

Won't get into active biamping because that wasn't the question and I'm not writing a book. Not sure if I would tackle the 801's xover without DSP.

The xover point (380 Hz?) makes passive biamping difficult. However, if you're determined, consider a "pro" amp like a Carver ZR1600 for the bass, which has variable gain. Then again, you could just get a capable amp to start with.

Don't remember that ever being popular. Probably more talked about than done, much less accomplished successfully. That said, a friend biamped with Manley Snappers and a Coda System 100 on Dunlavy SCIII's with fairly good luck, although it wasn't all luck for a guy that builds his own DAC and preamp.

There was a time when low impedance, 12 and 15 inch woofers ruled the land and were inexpensive enough to tempt partnering with cheaper amplification.

There was a time when many big amps were clumsy.

That time was called "The 80's" and the world has evolved, except B&W ;). Not all for the better. Perhaps the 80's should best be remembered for life before HIV.

As I said, it can be done. I've done it and learned a lot. Even with MOSFET amps of similar character but different qualities and a xover at 90Hz, matching was difficult. Tried a decent pot on the bass amp but was constantly fiddling with different volume settings and recordings and it never did sound right. Custom made an attenuator (23 step, 2 to 4 Kohm, SE additive) and that was leaps better. How's your soldering?

I've evolved to Genesis 350's with factory servo bass amp/adjustable active low pass (avoids passive inductors). Added an active high pass (NHT X2, simple, fixed 12dB/octave) at 30 Hz higher than stock passive. Next step would be full DSP, 3-way active with real time analysis and removing the passive completely and intact.

Not exactly.

In the context of this discussion and for 95% of the situations: Unless you happen to have amps laying around, one competent amp (or pair of monoblocks) is a better investment in time and funds than two "half" amps.

There's more complexity than has been mentioned. Ground loops, impedance, reactance, .... It's a journey that will let you know where you stand and where you're going.