True
So why do audiophiles still want some McIntosh at 200w to supply 90db speakers ? According to them, it gives more dynamics
Would be good that amir writes down an article on this
I gave that example of 8watts in the context listening at at low to modestly loud levels in a 'average sized' listening space.
If you plan to listen very loudly in a larger sized space the power demand goes up quickly as for every 3db of gain you must double the amplifier power output and then if sit 10-15feet away you will again need more juice.
If in my example a single 84db sensitive speaker hit 93db with 8 watts, it would need 16 for 96, 32 for 99, 64 for 102 & for 105db peaks it would need 128watts. But this was at 1meter.
At a typical distance of 3 meters you need 1150watts for a single 84db sensitive speakers to hit 105db anechoic peaks. Obviously less in a real room (about 30-50% of that) and less with a pair of speakers vs a single speaker. Not many 84db sensitive speakers can hit 105db anechoic cleanly nor handle 1150 watts (powered subwoofers often can and do)
Still, at VERY high SPL it would better to have that 90db speaker AND a big amp.
I use 400watt/channel amps. I tend to crank it up often and while 200watts would usually be enough it is the same price for 400-500. 50-100 is not enough for me in my main listening space. In my secondary systems in smaller spaces where high SPL is not used much= bedroom, garage, or my step sons room, 10 watts is plenty.
I also look for amps that can handle low impedances and still output lots of voltages. Ideally they would double power when going from 8ohms to 4ohms and again from 4ohms to 2ohms. If they do not double power you will lose some bass dynamics as the amp will not be providing enough voltage to speakers.
This actually could be a reason some high sensitivity speaker sound more dynamic, it isn't actually the speaker itself being more dynamic but rather the chosen amp not providing enough voltage at low impedances. If your speakers are low sensitivity and have low impedance zones get a real beefy amp.