How much power needed to drive 91db speakers?


Sonus Farber lists the sensitivity of my speakers at 91 db SPL@ 1 meter @4 ohms.  They also say I should use  50-450 watts of power. My PS Audio amps pump out 500 watts @4ohms, so the max isn’t a problem, but if I switched to something 15-50 class A watts, would that be more than enough power?  
 

Thanks in advance.

curiousjim

Showing 2 responses by audioman58

I  happen to have focal Sopra 2  speakers  91db efficient  at 8 ohms 

I have a 45wpc Pathos inpole  integrated amp 45wpv 8 ohms and 75 wpc into 4 ohms  my room is big 30x 16x8 but I only sit 11 feet from them  .itcan playinto 95db peaks it weighs 86 lbs and a dual mono design  .the question is how  often do you need to play a tear damaging level ?   In class A it does get warm over 100 degrees  sonically superior to class AB  and the Patented Inpol technology it uses the 4 vacuum tubes for again stage to power the speakers as well as to the resistor ladder preamp section , and has dual linear power suppliesforthepreampsectiin to  big inductor transformers ,Mosfets, then potted torroidal transformers to the output section  . For me it’s plenty loud and very tunefull and detailed Pathos makes a great hand built product from Italy.