old school amp question

[hpcbmw]

Hey Stereo gurus - My girlfriend had a 7 year old pioneer headunit. She got a 12" sub box put in the back by a shop about 3 years ago. Fast forward to now - the pioneer dies and i replace it with a $100 jvc unit. She thought they installed an amp with the sub, but I can't find it. The wiring was kinda wierd - lt rear pos to rt rear neg, or something like that. I didnt really pay attention, just chopped off the old wires and hooked up the new wires according to the jvc instructions - i hooked up the lt rear speaker to the sub.

Now, the stereo and sub sounds like crap.

I have two options - figure out the funky cross wiring the shop did, or try to install an old school amp that I took out of an old pickup - this amp had a bad rt channel. I don't have the cash to buy a new amp, but my girl is not happy because she can't go "boom boom" anymore (I'm talking about the stereo guys - get yer head of the the gutter!).

The old amp is a Rockford Fosgate 2600x, dynamic power = 2x 85w into 2 ohms, rms power 2x60w into 2 ohms. It's got a crossover card that can be slotted for high pass, low pass and full range. It's got rt and lt rca inputs. For outputs and power it's got: "b+", "ap" and "gnd". For "bridged output" it shows a diagram of l+ and r-.

I'm don't know much about stereos, so if any of you have some input, please dumb it down for me.

Here's what i'm thinking on the amp: b+ means hot to battery, AP means pwr antennae or amp wire from stereo, and gnd is ground. Am I ok so far?

Anybody know the shops funky cross wiring trick to avoid using the amp?

Thanks for any ideas!

[Newfie_dan]

you can download the manual for it here; http://www.rockfordfosgate.com/scripts/ ... 1084382075 you may have cut the remote wire off the old deck and not wired it up for the new deck. As far as sound goes that is usually in the settings of the deck itself. As far as finding the amp goes just follow the rca lines from the back of the deck to the amp, its almost always located close to the sub and it has to be connected to it via speaker wires. Depending on the size of the sub it could be mounted under the driver or passenger seat, but usually they are in the trunk. The way it was wired was for the bridge most likely and thats why the sub will not put out right.

[thumpinmx]

the shop probably bridged the rear channels on the deck... stupid move to beging with... then installed a inline low pass filter.....

[hpcbmw]

Thanks for the link to the manual. I wired the old Rockford Fosgate amp up to the sub and it sounds great now! Thanks!

I think you are right about "bridging" the channels to the sub, but i didn't find any type of low pass filter between the head unit and the sub - go figure.

Thanks

[tmac4t4]

let this be a lesson....sometimes its easier to do some research, and do the work yourself rather than pay some shady mechanic...especially when it comes to car audio...its really pretty simple to hook up..i mean, its color coded and labeled 99% of the time!

[hpcbmw]

thank you tmac, o learned one...