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 freediver

It depends on how loud you listen & how big your room is..If you listen at levels around 80db.in a small-medium size room 15 watts of Class A power will,IMO,be plenty..If your listening at levels above 80db.in a big room then you’ll need at least 50 watts Class A..
 Another factor to think about is the impedance characteristics..Your speakers may be 8 ohm nominal but they could drop far down into the 3 ohm region & have dramatic phase swings,which are highly stressing on an amp...

@curiousjim ,I have a small Chinese made Pure Class A integrated amplifier that is based on the original Sugden A21..Puts out 15wpc.@8 ohms & can drive a 4 ohm speaker...
 I would be willing to let you borrow it any time as it's just sitting in it's box..You pay round trip shipping...Cheaper than buying & trying...