200W amp driving 150W rated speaker (1 Viewer)

[Eric Lo]

Did anyone try it? What will happen to the speaker itself and the sound? The reason I asked is that the my speakers home are all 150W rated but some of the newer mid-high end receivers and amps have 170W or 200W per channel rating. I wonder what would happen to my speakers even if I can afford these newer mid-high end recevier/amp...

-- Eric

 

[Yogi]

You have absolutely nothing to worry about when driving 150 rated watt speakers with 200W amp. The reason being speakers only use a few watts at normal listening levels or in fact at loud listening levels. Its only during those millisecond transients do they use anything exceeding a few hundred watts. Think of it: a 90db/w/m speakers puts out 90 db of SPL 1m away for every watt of power. At 3m (typical listening distance) it still puts out about 85db for every watt. For two watts it will put out 88db (3db gain per doubling of power). So for 4 watts it will put out 91db of SPL which is quite loud. you couldnt sustain extended listening at 90db continuously. Now when you are watching a movie you could have a peak that goes upto 106db. In that case your speaker will demand about 120W from the amp. For 109 db it will demand 240 watts from the amp (which most capable amps rated for 200W RMS will be able to deliver) for the short duration. Now speakers are able to sustain about 4-5 times their rated power for short periods of time provided that power is undistorted and clean and unclipped. Speakers are not damaged by overpowering them but by too little power that is clipped and distorted.

So the moral of the story: Speakers are destroyed by underpowered weak amps rather than overpowered powerful amps. So even if you were running your speakers with a 1000W/ch amp you have nothing to worry about as you will only be able to take a certain SPL level but atleast your speakers will be getting clean undistorted power in order to reproduce those SPL levels.

So rest easy and get the most power you can afford.

Best of luck.