car audio - RC-Monster Forums

BrianG · 07.08.2009, 12:02 AM

Wow, 10v? Body resistance must have been very low to feel that. I can't remember the exact amp I was using (I think it was an old PPI PC2350 - 2x350w@4ohms) but I could only feel a slight buzz and that was at ~60vrms AC on the speaker wires in bridged mode.

Most people don't realize that it's the body's own reaction that kills them most of the time. It takes ~15mA (that's 0.015A) to severely hurt/kill you. Example: Take 120V. If your resistance is ~15Mohms, that's only 8uA (0.000008A). Ok, so you feel it, but it doesn't harm you. But, the body's reaction (heart pumping faster increasing circulation closer to the skin, sweating, etc) all lowers the body's resistance, which makes you react more, which further lowers the resistance until it gets to a point where that magic 15mA can start flowing and that's where the problem lies. If you could remain totally calm and somehow keep your body from reacting in this way at all, it would theoretically take 225,000V to kill you (assuming 15Mohm body resistance and exactly 15mA to be fatal).

J57ltr · 01:46 AM

Edit:I am sure it wasn't (or is ever) cool around here so it was probably fairly low.

Come to think of it, the truck had 2 45's bridged each on its own 15", so I guess that would have been closer to 20V RMS. I had each lead in a hand and we were trying to tell if they were out of phase on the first startup, so I had it up pretty loud. I used to work on those series of amps (among others) extensively. That was back from the transition from transistor based switching power supply to MOSFET based power supply.

Jeff

_paralyzed_ · 07.08.2009, 03:56 AM

Thanks everybody!

I always build my own boxes to suit the sub/fit the vehicle.

It will be four old school JL Audio 12w6's. Dual 6 ohm voice coils wired in parallel, then all 4 speakers wired in parallel.

A crossfire 1000d sub amp and a crossfire 402 for mids/highs(4 sets of components)

I have 2 1 farad caps, but I'll lose them.

JL claims a 3db(twice as loud!) increase with a ported box over a sealed, but they sound sooooooooooooo good in a sealed box, thats what they will reside in.