Speaker "Power Handling" ratings. What they really mean!

So you've seen speakers that say "1600 watts" and you think to yourself, where am I going to get an amplifier and the charging system to feed a sub like that?

Well, let's answer some common questions and clear up a few even more common misconceptions about power handling specs on speakers.

A speaker usually has two power handling ratings. "RMS" or continuous, and Peak or Max ratings, measured in watts.

I would first like to point out that these ratings are thermal ratings. This means that the power ratings are meant to tell you how much heat a speaker's voice coil(s) can handle as measured in watts, without incurring damage. It is important to realize that this has no relation to the amount of power the speaker actually needs to reach it's peak mechanical output. That amount of power is generally less than what the speaker "can take" and is dependant on both the speaker's design as well as the enclosure into which the speaker is placed.


It is also worth while to note that when looking for an amplifier to power your speakers, the "RMS" or continuous power output of an amplifier is measured by the manufacturer using a resistive dummy load on a test bench, with a pink noise test tone at full output. The reality is that in a car, driving speakers in a box or a door panel, listening to music, an amplifier will truthfully never put out it's "rated" power. The real output will be a fraction of that figure, and therefore when choosing an amplifier to power your speakers, you can, most times, safely choose an amplifier with up to 40-50% more rated output power (RMS/continuous rating) than your speakers' continuous power handling figure without concern of damage to the drivers.


Defining RMS and Peak power handling:

RMS (more accurately called continuous power handling) is the measure of how much power the speaker can endure for extended, continuous periods of use. This is an average rating since music, and thus the power required to produce it, is dynamic in nature and varies greatly from moment to moment depending on the frequency being produced and mechanical characteristics of the amplifier and speaker. *Note that the term "RMS" when applied to the word "power" is incorrect, as RMS or root mean squared only applies to AC voltage, but since the car audio industry has widely chosen to ignore this fact, I have chosen to use the term RMS as does the industry, so as not to confuse the average consumer even more than has already been done.


When pairing an amplifier and speaker or speakers, you should try to match the amplifier's power output to about 80% of the RMS rating of the speakers, at the load they'll present to the amplifier. This is a good, safe region to aim for if you're unsure of how much power the speakers actually need, and is a very generalized rule of thumb.

Note that RMS ratings for speakers apply to a clean, AC voltage being applied to the speaker. If the signal is clipped in any way, the resulting DC voltage will cause the coils to heat more quickly and to greater temperatures, causing damage at what may be an amount of power well below that of the RMS rating.
The closer the amplifier's power output is to the power handling peak of the speakers, the easier it will be to damage those speakers if the amplifier enters clipping.


Peak ratings are strictly meant to tell you how much heat the voice coils of the speaker can take for a brief, momentary burst of power without essentialy blowing apart the speaker or melting the coils on the spot. This measurement isn't very useful in real world application so it's best left ignored for the most part.


In conclusion, please keep in mind that just because a speaker may say it's rated for 2000 watts RMS, that by no means implies that you actually need that much power to get full output from the speaker. In fact you may need as little as 300 watts RMS to achieve peak excursion in teh right enclosure. This is a common misunderstanding by a large contingent of the car audio world, and one well worth addressing. This is why many people will tell you that you don't always need thousands of watts of power to have a loud system. Increasing power is the least efficient means of increasing volume or output, after all.

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