So you have decided to upgrade or replace your car audio system. This can be a very simple task, or could become an all-consuming hobby that may deprive you of all your spare time, countless hours of sleep and perhaps a few of your hard-earned dollars. None the less, no matter what level you decide to take your upgrade to, the whole thing can be very rewarding if do some research and spend your money wisely.
One of the biggest problems with the car audio industry is it's lack of a governing body that establishes standards, and of course the extreme competitiveness of the industries many manufacturers. While competition can be great in terms of getting good value for your dollar, it also leads to the exaggeration of the performance of certain products.
As you read through these pages, you will learn a great many things. One of them is that several of the marketing efforts of manufacturers are misleading, the worst of which is the rating of power from head units. I have been testing car audio products formally for more than three years, and have always used the same method to test them. I use a clean sine wave signal as the source. If it's a full-range amplifier, I use a 1kHz test frequency, if it's a class D amp, I use 60 or 63Hz. I connect the amp to a set of 225 Watt ceramic power resistors. I have eight four-Ohm resistors so I can create any load I want, and dissipate up to almost 2,000 Watts reliably. I increase the output of the amp until I measure 1% distortion (the beginning of audible distortion) with my Terrasonde Car Meter. I then measure the output voltage with my Fluke True RMS multimeter. By squaring the voltage measurement, and dividing by the load resistance, I get a power measurement. For me, this is the only power measurement that matters, as it shows off an amplifiers continuous power production capability. Most of the head units I have tested produce around 7 or 8 Volts using this method. That equates to between 12.25 and 16 Watts of real RMS power. Where they come up with ratings of 50 or 60 Watts is well beyond me. A while back, in the late '90s, Orion car Audio introduced an amplifier called the Concept 97-1 (or might have been the 97-3, I forget now). It was essentially one of their 1,000 Watt 2100 HCCA amplifiers in a naked aluminum chassis. They rated the amp at 1 Watt into a 4 Ohm load. It was done on purpose to 'upset' the sanctioning bodies of autosound competitions, forcing them to adopt new classification techniques. Their efforts were successful, as all SPL sanctioning bodies classify their competitors primarily by cone area.
Another game that is played is that of how speakers are rated, in terms of power handling. I get in to a detailed discussion on that topic in the Speakers section. Sufficed to say that for general speaker purchasing purposes, the power rating should not be taken into consideration. Why? Because it describes absolutely nothing about the performance of the speaker. The frequency response, dynamic capabilities, radiation pattern and so on, all the things that matter to what the speaker sounds like, have nothing to do with the power rating.
Do your research with your eyes, not with your eyes. In the long run, you'll become a much more educated and informed consumer, and you will end up owning a much better audio system.