how much power

Speakers with a minimalist xover do not require very much power to sound good. Many of these exotic multi way speakers have very complex xovers that require mucho dinero amplifiers with enough current to power a small village due to the xovers gobbling up half the power before reaching the drivers. YMMV

Charles1dad,
By all means low-wattage amp can't reproduce real volumes of let's say acoustic upright bass even in the small room. High-efficiency low-wattage friendly speakers can't have sufficient bottom-end performance and lower efficiency full range speakers can't be driven by a few watts of power.

Marakanetz,
I agree with your 2nd point ( I clearly said amp has to match the speaker load demand-requirements).
Your first point I simply disagree with based on direct listening encounters over the years. A low power amp if matched with appropriate speaker(load and efficiency) will provide full and relistic bass(I know I`m not the only either).
If your experiences have been different no big deal I understand, but I know what I`ve heard. We`ll just have to agree to disagree that`s all.
Best Regards,

I'm running a dual transformer YBA amp which is 50 watts into my 86db Vandersteens, not a problem. I have a 200 watt Rotel and except for overall bass the YBA wins hands down. It's a small room and I listen to jazz mostly.

Sometimes there are exceptions to the audio rules.

My Ref 3A Grand Veena go down to 32 hz and my 2 watt SET amp delivers as much bass as my 1000 watt D amps did, and as much volume.

In fact I never have the Steelhead past 12 o'clock or the midway point.

The Grand Veena's crossovers (amp id directly linked to mid driver, tweeter, supper tweeter and woffers have crossover)are easy on my amp.

Here;s a ist of amps I auditioned in my system, before deciding what to purchase.
All amps drove the speakers well, didn't clip, and they all did the bass, to varying degress.

1961 Bell 18 watt tube push pull 4 6V6 tubes,
latest edition Mac 275,KT 88tubes, push pull,
Atmasphere S30-OTL,Grant Lumley -el34 push pull tube,
Art Audio Carissa, SET 845 tubes,
Pass labs Aleph 3-class A solid state
Red Draggon class D Leviathan mono blocks-1000 watts.

All the tube amps had a distinct sonic signature.
The Atmasphere and the Aleph had the best bass control.

The DecWare Zen Select-SET 2 watt, el 84 tube, was the purest of the lot, had no tube sonic signature, and did bass as well as any of the other amps.

I am more than pleased with the sound and dynamics this amp has driving my speakers.

After comparing it's sound with all the other amps, I found much to admire and nothing to fault,which should illustrate that you need to try amp/speaker combinations for yourself,and not rely on blanket audio statements and assumptions.

This is all the amp I need for my speakers and my taste in music runs from classical to jazz to rock.

There hasn't been a time on any type of music that I wished I had more power.

The only audio "truth" that I find applies, is that no amount of watts can improve the sound if the first few watts are not good.