Thread: rms question

Car audio is all about the power ratings. The objective is to match up the power of your amplifier with the power handling capabilities of your speakers or subwoofers. Seems simple enough…until they throw around words like RMS, peak, max and dynamic and then throw the word “power” after it. As a basic rule of thumb, RMS power is considered true power and all other ratings are relatively mute when making comparisons or finding that perfect system. Below I go a bit more in depth with the different types of power.
RMS Power Ratings:
The RMS power rating is the measure of continuous power that an amplifier can output, or a speaker can handle. RMS power is derived from Root Mean Square which is a statistical measurement of the magnitude of a varying quantity and is applied to voltage or current. Yeah…you can disregard that and just concentrate on the fact that RMS power should be what you use to compare any car audio products. Even the RMS power has its flaws and inaccuracies, but for the most part it’s the most accurate depiction of real, continuous power so far. Here is the kicker, the way a company calculates its RMS power is different for each company which then makes RMS power inaccurate as well. Not so fast, all products that are CEA-Certified are tested using the same testing methods and can be compared in an apples to apples fashion. For more information on CEA Certification, read our articles on CEA-2006 and CEA-2031 compliant devices.
Peak, Max or Dynamic Power Ratings:
No matter how you word it, this form of power rating refers to the maximum amount of power an electronic device can handle or output in an instant without damage. Often times this rating could be reached with a big bass hit or a very loud note in a song as it's played using the correct amplifier. We do not recommend that you use the peak, max or dynamic power rating when configuring your system because it does not reflect the products capability under everyday use. So why then is this power rating still listed if it’s somewhat exaggerated and unreasonable? Manufactures still advertise peak power because most consumers are unaware of its meaning and believe that larger numbers are better. Peak power is used to make a product seem more powerful than it actually is, sometimes even five or six times more powerful than the RMS rating.
And there you have it. Play it safe and stick with RMS power ratings while staying away from peak, max or dynamic power listings. Try to find CEA Certified products to get the best apples to apples comparison!

OK so I should focus on the RMS rating and forget about the max number. I was jw if that max number meant I could play around from 250-500rms to get higher numbers for burps etc in comps.

Charles "Chuck" McGregor, while serving as senior technologist for Eastern Acoustic Works, wrote a guideline for professional audio purchasers wishing to select properly sized amplifiers for their loudspeakers. Chuck McGregor recommended a rule of thumb in which the amplifier's maximum power output rating was twice the loudspeaker's continuous (so-called "RMS") rating, give or take 20%. In his example, a loudspeaker with a continuous power rating of 250 watts would be well-matched by an amplifier with a maximum power output within the range of 400 to 625 watts.^[6]

Originally Posted by 98GtpONcrack

I just read the opposite, someone said make sure the driver could handle more than the amp so the sub doesn't blow.

He said maximum aka peak. An amps peak is pretty much always more than double it's RMS anyway. Most 12V audio has an RMS rating for both subs and amps so match those up. You can blow a 2000w RMS sub with 500w RMS amp if you introduce enough clipping or too much gain or your ohms are mismatched etc.

To be blunt, you can safely run any wattage amp with any wattage sub if you know what you are doing. Safely, but not efficiently. A 20,000w amp going to a 200w sub is going to sound the same as a 200w amp going to a 200w sub if you properly set your gains.

You should have no problems with that 2500 watt amp, provided everything is connected properly and your gains are set correctly.

And that you have the proper sized enclosure.