Hi, Henno --

...how does this car stuff compare to home stereo equipment?

Pretty much the same, except, of course, the lower voltages yield higher amperages (as you well know, Mr. Ohm pretty well laid down the law on that one...) which in turn require heavier cabling.

The home setup you describe, if moved to a car, would require (according to the chart on page 88 of the IASCA rulebook) 4 gage cabling for a 12 foot run, assuming that the actual power draw was 1800 watts. (This doesn't take into account the efficiency of the amplifier -- i.e., 100% efficient would draw 1800 watts to put out 1800 watts; 50% efficiency would, of course, require 3600 watts input for the 1800 watt output. But you knew that.)

The IASCA chart actually lists cabling requirements for amplifiers as high as 750 amps. (Requires 0 gage cabling for a six foot run!)

Why would we need hundreds of watts in a car?

Hundreds of watts? Try thousands of watts. Try tens of thousands of watts. The lunatic that runs the stereo shop that I patronize has a big Chevrolet dualie truck with enough amplifiers that he puts out 18,000 watts of power. He uses a 50 watt amplifier just as a pre-amplifier to feed the six 3,000 watt amplifiers that run the speakers. (3,000 watt amps are actually 750 watts each at 4 ohm, but he's running them half-ohm mono. He can only run them for 5--10 seconds at a time, else all the smoke leaks out of them and they quit working.)

Now, clearly, sound quality is not high on his list. If I remember correctly, his entire sound stage consists of twelve 15" subwoofers. He's had to replace all the glass with 1/2" thick lexan, and reinforce the door latches. He has reached 169 decibels in unofficial testing, and 164 decibels in actual competition.

I'll betcha your stereo can't do that!

tanstaafl.





"There Ain't No Such Thing As A Free Lunch"