ya, so i run two 10s w/a cheapo swapmeet 75x4 amp bridged to the subs.
i just upgraded my best buy specials to JLs and they dont sound right. i know that i have to play with the amp and the gains and whatever jargon words there are to get em soundin right.

what i wanna know is whats the correct way to setup the subs/amp with the least chance of messin em up (blowin em).

also, my amp is 2ohm stable, i dunno what the JLs are rated at, but the way i have em wired is channel 1+ and 3- go to the left, and 2+ and 4- go to the right....

how can i maximize the output of the amp while retaining da thump??

tia, and i have read a lot about ohms/wiring, but can never really figure it out at all.
the subs arent wired in parallel, the leads to the speakers come from an rca jack that is spliced into my rear speaker wire...(ghetto)

thanks

First off, get a better amp, your JL's will thank you :) Ok, so what impedance(ohms) are your subs? I'm going to assume they are 4 ohm single coil subs. I'm not sure what kind of amp you have, but the general connection on 4 channel amps when briged is channels 1+2 is the one set, and channels 3+4 are the second set. From what you said, you are mixing the bridged outputs on the amp using 1+3 and 2+4. Don't do this. I'm surprised you didn't blow the amp yet. You say the amp is 2 ohm stable, which is perfect for a 4 ohm sub, since when you bridge two channels of an amp(combine left and right), the amp will see HALF of the load put upon it. Now the amp sees a 2 ohm load with the channels bridged on the one 4 ohm sub. The amp may have markings on it by the speaker output terminals on how to hook up the bridged + and - . Usually, you will take the + of channel 1, and the negative of channel 2, to get your connections for the one sub. Do the same for the other sub. Channel 3 is pos, and channel 4 is neg. Some amps are different!! It may be the other way around, like channel 1 is the negative terminal for the sub, and channel 2 is the positive. You will just have to find out. That amp is prob not even putting out much power at all, so i would get a good amp to push the subs, because you can easily BLOW a sub with too little power. The great amount of distortion will quickly heat up the voicecoil of the sub and blow it. It's much easier to blow a sub with too little power than too much, as far as distortion is concerned. Also, i'm not quite sure of how you hooked up the audio inputs to the amp. You have the stock head unit right? Do not use the rca inputs to the amp coming off of a speaker lead. This is TOO MUCH power input for the amp!! Get a line-out low level converter. This hooks up to your left and right speakers, or really taps off of them to get a signal, and converts, or turns down, the level of voltage and signal to the needed rca plugs. Some amps have "high level" inputs, which then you can hook those up directly to your head units speakers output wires. An amps rca input needs anywhere from 1-8 volts of singal input for the audio. The stock head unit's speaker output wires are higher than that, and that will kill the amp too, if you leave it connected like that. I'll bet the amp is very loud with the gain control all the way down, huh? Get a converter, and that will help. Also, be sure the subs are "in phase", meaning that the pos is connected to the speaker's pos, and the other sub is identicaly hooked up. You will know if it is out of phase, if you use your balance control to fade between the left and right channels. If the bass increases when you go full left or right, then one of the sub's pos or neg is reversed. Just take one sub's pos and neg and reverse their connection. Ok, i'm done :)

The way to set subs is to put gain to 0 and put head unit to about 75% volume, then keep upping the gain until the subs start to distort and then back it down a bit. Any distortion you do get will prolly be coming from the head unit and/or amp and not the JL's.

Wiring wise there is not much you can do with 2 subs and 4 channels.
You have the best setup already. For future reference though make sure the amp is 2 ohm table in bridge mono mode too, not just stereo mode. Alot of cheaper multi channel amps aren't

ya, thanks for your input fellas... the rca leads goin to the amp are 1- 2+ and 3- and 4+, mah bad... i swapped around the speaker wires, pos/neg and they sound much betta... still havent played with the gains at all, but i will soon enuff...

im not sure what kinda ohms the subs are rated at, but they are one helluva upgrade compared to my bestbuy specials...
its like i have to listen to all my CDs again to hear the bass i wasnt hearin b4...

I think most likely you just need an amp with more power, since JL subs can take about 300 watts rms each. A 75x4 run in bridged would only give you probably 75 watts to each sub if I'm not mistaken. It can also be the box, because my friend with JL's sounded much better after changing boxes and the direction of the subs.

Actually, if you are bridging your amp and the power rating of 75x4 is rms, then your amp should be putting out around 300x2@4ohms. More then likely if it is a "swap meet" amp then the actual power rating is probably much lower then 75x4. The best fix is to get yourself a good amplifier. Remember, you can easily fry your subs by under powering them!

I agree with a majority of the above posts, but just to let you know, you are NOT going to harm your subs by clipping (distorting) the signal with that amp. I just didnt want you to be afraid of hurting anything.

Power kills subs, not distortion. In order for distortion to do any damage whatsoever, the subs need to be operating VERY near to thier thermal power limit anyways, and played for an excessive amount of time.