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# What on earth does RMS mean?

I have two large dual 15" Loudspeakers - The label on the back reads that the its 8ohms - and I understand that - but it is the Watts that I don't understand - it says it is 250 Watt RMS , and 500 Watt Peak - Can somebody please explain the last part to me - In simple terms please!
Member since:
October 21, 2006
Total points:
113 (Level 1)

RMS is "Root Mean Square". It is a measurement of AC Power. It is 70.7% of the peak power. It is the effective power used by a device. I have no idea why your speakers state 500w Peak and 250w RMS since 500w peak is 352.5w RMS. Maybe they are being conservative with the effective power rating so the user does not over power the speaker.

To simplify: Basically you just want to do apples to apples. If your amp or stereo ouput is rated in RMS or Peak that is the measurement you would use to for the power that speaker will handle.

Ex. If your stereo output is 250w RMS/channel or less your speaker should handle it since it is rated at 250w RMS. If your stereo power is stated as 500w Peak/channel then your speaker should handle that as it is rated at 500w Peak. Hope this helps. www.GIJoesRadioElectronics.com

### Source(s):

Myself, owner/tech: http://GiJoesRadioElectronics.com - Two electronics degrees from Central KY Tech and Devry Columbus.
I dnt know why I selected yours as best - I think I just like your website :-P

But thanks for all the answers guys - I think I get it!

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• by Stefy
Member since:
October 21, 2006
Total points:
393 (Level 2)
RMS means Root Mean Square. RMS is basically a way to calculate the actual power of an AC wave. Since a wave goes from peak to peak, it's apparent power is often more than the actual power of the entire signal.

### Source(s):

• 1 person rated this as good
• by Soulmate
Member since:
October 21, 2006
Total points:
866 (Level 2)
RMS stands for Root Mean Square as mentioned previously

its a measurement of the power output from the audio and they call it Mean coz it takes the calculation of the power and it gives the average sound not loud not low

i think this is the best description in a simple way :)
• by drivespl
Member since:
October 21, 2006
Total points:
237 (Level 1)
When you amplify a speaker RMS is the continuous wattage it can handle peak is when the music bursts like bass or a scream.
Another important thing is spl how easy the speaker turns watts into sound 3 more db's is 2 times as efficient or loud.
I hope this is usefull to you.

### Source(s):

crutchfield.com
• 1 person rated this as good
• by Alan J
Member since:
August 26, 2006
Total points:
1,503 (Level 3)
What the heck. I'll try to explain it, too. Think of your power output as a wave. The highest it goes up to is 500 Watts, but it doesn't stay there long. It goes back to zero and then back up again. Some people will tell you it goes negative also, but you can ignore that. This doesn't make any sense when you listen to music because it's not like the volume goes up and down like a wave. That's because the wave has been converted to give you a continuous output of 250W. So when you see 500w on an amplifier, or they'll probably say 1000W because they will add both channels, it's kind of a lie. The RMS is what is really coming out of the amp. And most people don't even get that because you have to have really high input voltage to make the amp work like it should! But that's another story.
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• by johnny d
Member since:
March 14, 2006
Total points:
839 (Level 2)
RMS stands for Root mean square.

i would love to break it down further but since i never did so hot in physics, im afraid that is negatory.
• by Loz T
Member since:
May 09, 2006
Total points:
3,278 (Level 4)
The RMS value can be thought of as the "power content" - generally, the heating effect. If you have a 1kW electric fire, and apply 110V ac (RMS) to it, it will produce that amount of heat - the same as 110V DC. However, the actual peak voltage is in the region of 155V, but it only stays that high for a moment before it goes back down. Think of the RMS as the average figure between zero and 155.

With your speakers, 250W RMS is the maximum continuous power they will carry. Peak power figures with audio equipment are usually pretty meaningless, but a rough idea is how much you can get with a single surge - a cymbal clash, for example.

Use the speakers' RMS figure to match them to your amplifier (about 200-300W of amp), and ignore anything that's not RMS.
• by C M
Member since:
September 06, 2006
Total points:
2,495 (Level 3)
Riverside Middle School!!
lol that's my schools initials.
• 4 people rated this as good