Originally Posted by Jmac
Here's something I hope you can will all use to your benefits. As you may or may not have noticed, most equipment dies for one simple reason : Most people push their equipment beyond its limits. Whether its the amplifier or subwoofer or speakers, clipping is the number one cause of failure that I see. To prevent clipping, I've made this tutorial (Well, JL Audio did, but I've been doing this for years before they put it on their site).
Okay, before I post the links, there's just one problem that I have with the following guide. It says to use 75% of max volume. I don't agree with this at all because, with some head units, you can crank it up to full without distortion and with others, it may only be 60% ... To set your gains, use the MAX settings you'd NORMALLY use ... If the loudest you listen to your music at on a regular basis is 22/35 with bass @ +3 and treble @ 0 with MX on, by all means use those settings. Also remember to have the car on It should also be noted that if you want to use bass boost, set it prior to the gains and use the center frequency of the bass boost (45 Hz for most amps) as your test tone ... Please remember that if you have a subwoofer volume control, set it to full before you set the gains on the sub amp ...
Here's the formula you'll need ...
Sqrt(Power*Resistance) = Voltage
(i.e. If you bridge a 4 ohm subwoofer to your amplifier that is rated to produce 100 RMS @ 4 ohms in bridged mode, you would want Sqrt(4*100) = 20 volts)
Gain Setting tutorial ...
JL Audio: Car Stereo, Speakers, Amps, Home Theater
Test Tones ...
http://www.teamtreo.com/view.php?showme=Free_Test_Tones
Hopefully, this will all result in greater longevity of your products and cleaner bass. Some people still insist on cranking the gains after using this tutorial because it's "not as loud as it was." If you choose to do so, you may be putting your equipment at risk. If you find that you find the output is too much, feel free to turn the gains down.
from this i have gathered, take the output of your amp*resistance woofer will be wired to and sq rt it. in my case, 1600*1= 40 volts on the amp. correct or is dooski's explanation correct. I thought i had this down, now I'm all confused again