Don't believe the hype! Probably one of the most common myths that I would like to address is audio car amplifiers' power ratings. Audio car amplifiers are rated by the manufacturer to indicate what type of power they are capable of. Often times, however, manufacturers advertise an exagerated power rating to boost their sales. This practice is most common on low-end manucturers' amplifiers. Unfortunately, there is no standard or mandate that governs how audio car amplifiers' power ratings are derived. When shopping for a car audio amplifier, it is important to note the ratings on the amplifier and, more importantly, what voltage and load the ratings were accomplished with. For instance, you may see an amplifier that is rated at 100 watts per channel at 12 vdc at 4 ohms resistance. This is a fairly good, real world rating because 4 ohm speakers are still the most common variation on the market and nearly all automotive electrical systems are capable of 12 vdc for sustained periods… after all, they were built for that. Now, on the contrary, you may also see an amplifier that is rated at 100 watts per channel at 14.5 vdc at 1 ohm. This power rating is less realistic because the amplifier may not be capable of a sustained 1 ohm load, you may need specialty speakers to run at 1 ohm, and your electrical system may need upgrades to produced 14.5 vdc for prolonged periods. It's just not realist! Furthermore, be on your guard for car audio amplifier manufacturers that do not disclose how they achieved their numbers. Any amplifier that simply has a huge number stamped on the top is typically an amplifier that you should steer clear of. See the image example below.
I was nice enough to blur out this amplifier's manufacturer name. They have done enough harm to their name over time… they don't need further bad press from me. This car audio amplifier uses a unique power rating system that I refer to as I.F.S. (If Lightening Strikes). The only way this audio car amplifier could produce 1000 watts would be to hook it up to a receptacle in your house.. and even then it would only hold out for a fraction of a second before it let the magic smoke out. 
This concludes Part 1 of "Common Amplifier Myths". I will be continuing this series of articles as well as starting new articles for other car audio components. Believe me, there are plenty of myths out there. Check back often!