Sensitivity is the efficiency of the Loudspeaker . Having modified alot of Loudspeakers ,the size can have something to do with it as well as drivers and
most of all the Xover and how complex it is. It’s always better to have more power ,
for in transients if youare playing loud peaks can go up 10 times that for
a short fraction of a second and the amplifier can clip or distort which isnot good forthe drivers if a speaker says15 watts that’s minimum it is not full range
and too what is the speakers capability ,in bass ? Many companies stretch the truth there is no standard ,a speaker can say 38 hz but it maybe at + or - 6 DB which in truth speakers start to roll off earlier then the rated specs ,a good review will show
a waterfall plot in how linear it is , I was watching and reading a Perlisten speaker review. They are very linear ,not many dips at all , that’s why allways buy quality
and as much amplifier you can afford to have overhead , more so if you are playing
constantly over 85 db spend $30-50 on a good SPL level meter to see how loud
you are playing . I have a Dynaudio speaker it says 87 db But it can dip down to 3 ohms which is pretty demanding I have shut down a 100 watt amp and my speakers are a 4 ohm loud I went to a amplifier that doubles it’s rating 150 8 ohms
300 wpc at 4 ohms .