Have heard great sounding combinations of low powered SET’s and high sensitivity speakers (make that horns; all-horns or horn hybrids), not in the least lacking transparency, dynamics, "ignition," tonality and what have you - on the contrary. To me they’re usually much more alive sounding vs. low efficiency, direct radiating speakers coupled to SS amps in the many hundreds of watts, a combo of which that can sound downright dull and bottleneck-ey by comparison. This, it seems, mostly comes down to the speakers being the weaker link here; very high sensitivity horn speakers can do with 1 watt what a low sensitivity speaker would need more than 100 watts to achieve, and then a 5-10 watt SET is suddenly transformed into a beast with large form-follows-function horn speakers (often fitted with pro drivers) in the receiving end to whom thermal compression is practically irrelevant.
Conversely: at the other end of the wattage scale it’s interesting to see how watts in abundance are sometimes scoffed at, maybe because the amps delivery that much power are either insanely expensive (and absurdly heavy), derived from the pro sector, or that much power is simply regarded as ludicrous excess. In my own case the power amp actively driving the 100dB sensitivity dual 15" woofers per channel of my EV main speakers, the Lab.Gruppen FP6400, can shell out 2.3kW into the 4 ohm load they present, while a 30 watt pure Class A power amp is actively driving the 110dB sensitivity MF/HF horn section above. A 500 watt power amp drives a pair of subs (97dB sensitivity), actively as well, so about 2.8kW in total per channel. Too much? What does that even mean? It’s utterly effortless at any SPL one desires, sounds great, and you don’t think of wattage per se; just uninhibited, full, low distortion and clean sound.
Needless to say, context is very important.
