Speaker Power Rating, RMS or Peak?

[davyvan]

Here is my newbie question: Are quality speakers rated for RMS continuous power or dynamic (peak) power? On the rear tag of my Infinity RS2 Monitors (8 ohm) it says 15 to 100 watts, not specifying whether RMS or peak, and I'm considering purchasing a nice Sony STR-GX5ES II 2 channel receiver, rated at 80 WPC RMS 8 ohm, 120 WPC max dynamic. These are great sounding speakers, I'd hate to ruin them by cranking up the volume as I sometimes do.

 

[whoaru99]

Mostly neither.

Unless you are looking at clearly-defined ratings such as often the case with pro audio gear, consider the speaker ratings for consumer gear only as a rough guideline for what size of amp is appropriate.

There really is no sure bet that you can just crank away willy-nilly without regard for consequences regardless of ratings.

The best bet is use your ears. If something doesn't sound quite right then turn it down. Obvious signs are popping or clunking noises from the speakers, or if the sound goes from rich and full to rather flat/one-dimensional and a little harsh sounding. Both signs you are exceding what the speakers or amp/receiver can deliver cleanly.

 

[davyvan]

My current receiver is 40 WPC RMS 0.8% THD and the highs sound a bit harsh (not clipped) at louder but not deafening volumes listening to CD's. It is an older Sony STR-AV2200, not high-end by any means, just an OK basic receiver. Am I hearing the receiver's limitations and pushing it too hard?

 

[whoaru99]

My current receiver is 40 WPC RMS 0.8% THD and the highs sound a bit harsh (not clipped) at louder but not deafening volumes, it is an older Sony STR-AV2200, not high-end by any means, just an OK basic receiver. Am I hearing the receiver's limitations?

The harshness you hear as you start cranking it up can be a sign of clipping.

Clipping is not as black and white as turning a light bulb off or on.

It starts small, so small it's nearly impossible to detect by ear. But, it gets more and more as you push the amp harder. One of those signs can be that harshness starting to develop. If you hear really bad stuff you are already well beyond where clipping started.

 

[davyvan]

So I'd likely be safe with a cleaner 80 WPC RMS so long as the speakers aren't pushed to the limit? Sounds like my present receiver is working too hard.

 

[whoaru99]

The only guarantee of "safe" is how you run the system by identifying when you are pushing it too hard.

My gut feel here is you're on a spiral case of not enough rig for the gig. They speakers you have are relatively small bookshelves. Regardless of power there is only so much crankability available from them. You'll up your power but it still won't be enough system for your cranky-time needs. I could be wrong, but that's what I'm reading between the lines.

 

[davyvan]

Thanks, specs are a good place for a novice like myself to begin, and then I'll trust my ears.

 

[whoaru99]

FWIW, going up to 80W from 40W is a 3dB increase. While it will afford a bit more clean headroom if you don't try to push much harder, max volume will be only a slight increase.

It takes 10x more power to be twice as loud, all other things equal.

 

[davyvan]

Headroom being undistorted sound?

 

[savatage1973]

FWIW, what I have learned over the years is that speaker wattage (power handling) ratings are pretty much irrelevant, as are their impedance ratings. I won't even open Pandora's Box of vintage vs modern vs tube wattage ratings of amps/receivers--that has been argued in other threads. The single most important factor has already been addressed--if it starts to sound bad, turn it down--it is really that simple. Then you can determine what the "weakest link" is--too much power for the speakers, bad source, or too little power from the amp for the speakers. And then there is the room--but I digress--what are you expecting them to do?

I run speakers that are rated at 50W max on a 300wpc amp and I also run speakers (that are half the physical size) rated at 175W max on a vintage 24wpc receiver, and both combinations sound good in the rooms that they are in.

8 ohm impedance is a "nominal" rating--"most" speakers are a highly reactive load across the frequency band with dips and peaks. So 8 ohms is an average or some sort of compilation of the reactive load.

Then there is "synergy"--and it is very real--some things just don't "play well with others"--you'll know it when you hear it.

 

[whoaru99]

Headroom in this context means unused power above what is necessary for the average level. This is what you need to cover short term peak demands with no or minimal clipping.

If you get more power and use it to just crank it up proportionally more then you have eaten that headroom and are back at square one, just at a louder square one.

 

[savatage1973]

Headroom being undistorted sound?

Headroom is on both ends--speakers as output and amplifier as source. Music is not a bench tested sine wave or pink noise generator--it is a dynamic Headroom on an an amplifier is the ability to produce greater than its rated output for milliseconds to cover transients, same for speakers--the ability to handle transient spikes above the RMS rating.

 

[davyvan]

That sounds like good advice, I'll get the larger Sony receiver and likely enjoy slightly cleaner sound, if not I'll save it for later. Nice condition, powers up, screamin' deal for $20 at the 2nd hand store so no big risk, except speaker damage if I'm not careful.

 

[davyvan]

Gotcha, I'm not seeking a louder volume level, only cleaner sound. Getting back to the speakers I think the 1997 Infinity RS2 bookshelf speakers are great for the music I love, rock, pop, soul. Do these speakers have a good rep?

 

[savatage1973]

That sounds like good advice, I'll get the larger Sony receiver and likely enjoy slightly cleaner sou.nd, if not I'll save it for later. Nice condition, powers up, screamin' deal for $20 at the 2nd hand store so no big risk, except speaker damage if I'm not careful.

For $20, what have you got to lose? It should pair well with those speakers in terms of power. Caveat applied--I am in the camp of "you can never have too much power"--that doesn't mean that you have to use it all, all of the time, but it's there when you need/want it. Just be responsible with the "loud pedal" (volume control).

Gotcha, I'm not seeking a louder volume level, only cleaner sound. Getting back to the speakers I think the 1997 Infinity RS2 bookshelf speakers are great for the music I love, rock, pop, soul. Do these speakers have a good rep?

IMO (and this has been heavily debated in other threads), you can never have too much power. I am not intimately familiar with either that receiver or speakers, but "headroom" is a very valid point. "MOST" people rarely use more than a few watts for typical listening, but some of us like to "get it on" every now and then.