Speaker wattage question

paraneer
639 posts
08-10-2016 5:09pm
Speaker wattage ratings are generally meaningless. The two key specs are impedance and sensitivity when matching an amp to a pair of speakers.

I wouldn't say that speaker wattage rating is generally meaningless - it does have a function. And that function is to generally make the user aware how much wattage the cone drivers can handle before they start distorting. Even tho' one is going to hit those max wattage numbers infrequently, one needs to be aware of the max wattage handling or one is going to break/fry/destroy the driver(s) with too much power. Personal experience confirms this. If the max wattage handling of the speaker was not mentioned one could do a lot more damage more quickly than if this spec was stated - i.e. you know whether you can go all out with your amp or not. For example - my DMT10 speakers can handle 350W & they are connected to a 120W/ch amp. I know that even i crank the volume to max, i will not destroy the drivers. OTOH, my Scintillas can handle 200W max so I cannot crank the volume to max as my amp can output 1100W into 1 Ohm. If I didn't know this I'd have fried the ribbons by now....

I agree with you that speaker wattage handling spec is not what one uses to match amps to speakers.
good additional point by georgelofi.  

Look at this review and you can see that the reviewer used a pair of Anthem Statement M1 monoblocks which are rated at 1000w.

http://www.soundstagehifi.com/index.php/equipment-reviews/557-kef-ls50-loudspeakers 

" Then, for the heck of it, I tried the LS50s with the Copland CTA 506 ($6000), a tubed stereo amp that puts out 90Wpc into 16, 8, or 4 ohms; as well as a pair of Anthem Statement M1 monos ($3500 apiece), a proprietary class-D design capable of unbelievably high power (1000W into 8 ohms). The sound was slightly different with each amp, but one thing remained the same: the diminutive LS50s sounded much bigger than their size let on. I also learned that, with any of these amps, the LS50s could play loud -- louder than I expected from speakers of their size, and louder than I really needed them to."

Unless you get really crazy stupid loud with your Parasound, I don't think it's 165w/channel will be a problem.

Bill

bombaywall- That's my situation. I had a NAD Viso Five @ 65 WPC, so I knew I never had to worry. Now I possibly do.


So, the general opinion is that if I hear distortion, turn it down. Otherwise I should be fine?

And, willand, they do play loud. The sound is much larger than their size would let on. I'm pretty blown away. That's why I'm asking this question. They sound fine very loud, but I don't want to cause damage.

Chris, Lots of good information above.  Just to expand on a couple of points - music in general has relatively little energy at the frequencies handled by the tweeter and these drivers are not designed to handle a lot of energy.  Once an amplifier is pushed into clipping it begins to generate harmonic distortion.  The distortion products relevant to this discussion are caused by the summing of fundamental frequencies in your music which produce higher frequencies.  Harmonic distortion is present in all equipment to a (hopefully) small extent but in most clipped amplifiers this distortion increases dramatically.  Your speaker's crossover dutifully routes any of these signals higher in frequency than the crossover point to the tweeter, increasing the likelihood of damage.  This is why the interaction between  your amp and speakers (impedance and negative phase angles), especially in the frequency ranges where most music - or the music you listen to - resides and why it's important to know your speakers impedance characteristics (see JA's measurements in Stereophile) when matching an amplifier.  As has been said many times, far more speakers have been damaged by pushing an underpowered amp into clipping than by playing a powerful amp loudly.  Dick

Harmonic distortion is present in all equipment to a (hopefully) small extent but in most clipped amplifiers this distortion increases dramatically. Your speaker’s crossover dutifully routes any of these signals higher in frequency than the crossover point to the tweeter, increasing the likelihood of damage.

well explained djohnson54. One point that djohnson54 made that i’d like to elaborate on - when the amp goes into clipping, the output music signal looks like it has lopped off tops & bottoms. The lopped off top comes from the fact that the output voltage maxed out to the B+ power rail. Anytime you have a music signal with sudden changes in amplitude it is like having a high frequency content in that signal. Sudden changes in amplitude = amplitude changes happening fast = high frequency content. So, it is this high frequency content that is dutifully passed onto your speaker’s tweeters (x-over is simply just doing its job). And, like djohnson54 wrote, the tweeter is not designed to handle high(er) power as there is not much hi freq energy but the clipped signal from the power amp does have high(er) power. And when this hi freq distortion power exceeds the tweeter’s power handling capacity, you fry your tweeter.....