Why do you need so much power?


I have a basic question.  I have a set of Tannoys with 93dB sensitivity. I’m told that a 25 Wpc amp like the First Watt J2 can power it just fine. (I don’t crank it to 11.). Someone also suggested an Emotiva amp with 500W RMS. 

So my question. Assuming you have a good set of speakers that are efficient (>90) and you don’t crank it till it’s clipping, then do you ever need such power as the Emotiva?  Thanks!
ssmaudio
I used a Bedini 25/25 with the Quad 57's for years. Perfectly satisfying! But that speaker is severely limited by power handling and easily damaged.
2 watts, 20, 35 watts, etc etc. 

  there is no substitute for headroom, and having the reserves for those crescendos’ / peaks / quiet passages......and the full on massive orchestral frenzy of woodwinds, bass, as the fury of the full orchestra slams you like a ton of bricks,......... you will need the watts, to make the smooth transaction from the small flute, or simple cello, to the full orchestra smash which happens awesomely in classical music.
  Not having the reserve and power to deliver these peaks will result in unhappiness. 
 Speaking from experience. 
https://www.youtube.com/watch?v=Sg14jNbBb-8

 
I have a 4 watt Decware tube amp with 92db Ref 3A de Capos.  Plenty loud in my 12x22 room, listen to rock, blues, folk and jazz
not concert loud
The same reason people drive 250+ horsepower cars - effortless performance. The Emotiva has WAY more power than you will need, so it will never strain. Another BIG factor is that Emotiva's are reasonably priced. I have an 8 wpc amp that costs more than the Emotiva! Your friend wanted you to get a bargain! It will certainly cost less than anything from PASS labs (I have two pass amps, not complaining). By the way 80 watts sounds only about 3X louder than 8 watts. To sound three-ish times louder than 80 watts, you'd need 800! Keep Smiling!
@boomerbillone

The same reason people drive 250+ horsepower cars - effortless performance. The Emotiva has WAY more power than you will need, so it will never strain. Another BIG factor is that Emotiva’s are reasonably priced.


while there is some truth to what you say, i would only add that there is a very important dimension of quality that matters, not just quantity of watts... if the objective is indeed to achieve great sound