Introduction
Car stereo amplifiers are used to boost the incoming signal from the head unit or stereo, and direct the new, more powerful signal to the speakers. These amplifiers are very complicated and different qualities exist. A cheap amplifier will advertise peak power only or will double the number of watts put out by each channel for a "total" power rating, which is misleading.
How They Work
Through a series of inductors, transistors, conductors, resistors, rectifiers and capacitors running through a computer-like circuit board, the electrical signal coming into one end of the amp is boosted and released out the other side to the speakers.
RMS vs. Peak Power
The RMS, or root mean square rating of an amplifier is approximately 70% of the peak output the amp is capable of. For this reason, simply advertising the peak power of an amplifier is not the correct way to do it, because the amplifier is only capable of these numbers for split seconds. To figure out the actual output of an amplifier that advertises 400 Watt Peak Power, for instance, just multiply the peak number by .70, and then subtract the new number from the peak and you will be in the ballpark of actual constant RMS output.
Fuses
Another way to get into the ballpark of actual power ratings is to look at the amperage rating of the fuse the amplifier calls for, and multiply that number by six. For instance, if an amplifier advertises itself as 320 watts, and calls for a 20 amp fuse, this formula tells us that the amplifier's rating is actually closer to 120 watts, so it can be assumed that they doubled the channel wattage numbers or took the peak rating as the amplifier rating.
Bridgeable Amplifiers
The term "Bridgeable" simply means that the amplifier has the capability to combine the left and the right channel wattage into a single output for one subwoofer. Many amplifiers are not bridgeable, however, so read the manufacturer's recommendation before bridging the channels. To bridge an amplifier, simply place the negative cable of the speaker to the negative terminal of one channel, and the positive cable to the positive of the other. The combined power will send the total of both channel's power to one speaker.
Tags: amplifier rating, ballpark actual, channel wattage, Peak Power, peak power, rating amplifier, that amplifier
