One Monoblock or Two?

Biamping would only be an advantage if you use a line level crossover, so that each of the amps only sees part of the frequency range.

Furthermore, the principle advantage of biamping is to reduce intermodulation distortion, and today's amps do not have the IM problem which existed a few decades ago.

Bi-ampling will make sense ONLY if speakers you use are very difficult to drive and create gross distortions with both of these two configurations.

For example, lets assume that the source of the distortions lies in low frequency area. If you use one monoblock then these distortions are spreaded across the spectrum including ear sensitive mid-range. If, on other hand, you use two monoblocks then you limit audible distortions , in this example, only to bass area which is less ear-sensitive and keep your midrange and treble pristine.

The power by itself tells me very little as some speakers need high current but others need high voltage.

All The Best

Simon

First, what do you call a 'difficult load'? Are you just referring to impedance / sensitivity? Or, the rest of the equation. If you have to ask what that is, you need to know.

Please check out the link on bi-amping. good information for down the road.
http://sound.westhost.com/bi-amp.htm

I especially recommend section 1.4

If you bi-amp, you probably don't want 2 - 300 watt amps instead of one 600 watt amp. The high frequencies need much less power than the lows, so it usually makes more sense to use a fairly large brute force amp on the bass half, and a much smaller but hopefully higher quality amp on the treble half (finesse!).

The details depend on speaker specifics, but a simple down the middle split you describe will waste a lot of amplifier. The unused reserves of the large amp on the treble side are not available for peaks on the bass side. The treble amp loafs while the bass amp works hard.

A better split might be 300-400 watts on the bottom and 30-40 watts on the top. Again, the devil is in the details and this should not be taken as a recipe.

You also have to consider gain matching of the amps, unless you use an active crossover (recommended). If you use an active crossover you will also want to bypass the speaker's passive crossovers if possible. This of course opens other cans of worms....

You also need to consider the sonic signatures of the amps used on the top and the bottom. It's safer to stick with the same brand line, but you can sometimes get great results by breaking that rule. A low powered tube amp on the top combined with a large solid state amp on the bottom sometimes works well.

You will have years of audiophile nervosa ahead of you!