This amp displays its peak power rating of 1000 watts, but its RMS power is actually 165 watts (times 2 channels at 4 ohms).

Last April, the online business newspaper TWICE (This Week In Consumer Electronics) ran an interesting article on a new approach to marketing mobile amplifiers. The article, "Car Amplifier Watt Wars Heat Up" by Amy Gilroy, described how various car amplifier manufacturers had begun promoting peak power ratings over RMS ratings. Some of the leading amplifier brands started "badging," or stamping, the peak power rating directly onto the chassis of their amplifiers.

The thinking behind this marketing maneuver is simple — most consumers don't understand the difference between peak power and RMS power, and when they see the peak power rating, they think they are getting much more bang for the buck.

RMS or Peak?
The difference between RMS and peak power ratings is a crucial concept for the A/V shopper to understand. Peak power ratings refer to the amount of power an amplifier produces, or a speaker can handle, for a brief musical burst — like the crack of a kick drum. RMS power describes the amount of continuous power an amplifier produces, or a speaker can handle. The RMS power rating is always the more significant number, as it is a more accurate reflection of a component's performance in daily use.

A widespread phenomenon
Car amplifiers are not the only products advertised by their peak power ratings. In-dash receivers have been marketed using this kind of approach for years — the general practice is to silkscreen the peak power onto the receiver's faceplate.

These receivers all display a power rating of 50 watts x 4 on their faceplates, though their RMS power ratings are 22-23 watts.

Why would anyone consider buying a 50-watt external amplifier when they think they can get 50 watts of output from their in-dash receiver? You can see here how quickly a consumer can get confused.

It's important to note, however, that manufacturers are not exaggerating the peak power ratings on their amps and receivers. This is a question of emphasis, not validity. And it's up to the customer to understand the difference between peak and RMS power.