zehnd

I want to make sure my Subs are getting the right power. I can't seem to get this stuff into my head.

I recently picked up two of these subs. JL 8W1v2-4

Specs are here. They say I should have 125 watts powering them for optimum, 50 watts minimum.

JL site

I have a Alpine MRV-F340 4/3/2 Channel Amp. Two channels supply my fronts. The other 2 are supplying my Subs. Each sub on 3 and 4 channel.

Specs of the amp.
Power Output: RMS Continuous Power (at 12.0V, 20 Hz to 20
kHz)
Per channel into 4 ohms MRV-F340: 35Wx4
Per channel into 2 ohms MRV-F340: 45Wx4
Bridged into 4 ohms MRV-F340: 90Wx2

With the way I have them hooked up, I don't think they are getting the minimum required. They do sound good right now.

Should I bridge the subs? If I should bridge them. Would both positives of the sub go to the + of the amp, and both negatives of the subs go to the - of the amp?

Thanks

white924s

In a word, no. The 8w1's aren't huge subs, but I'm pretty sure that you'll need more than the 40 or so w. that the Alpine is putting out. Do you really want 2 subs? You can probably run just one sub off the rear channels bridged and get good sound out of that, particularly if you're running 4x6's or similar up front.

I would strongly recommend against running them in the setup you drew in black. You're basically running them in parallel, which drops the overall load that the amplifier sees to 2 ohms (if my math is correct). That's much lower than what the amp is rated for and you'll overdrive the circuits and blow your amp pretty quickly.

If you really want to run 2 subs, you'll need a bigger amp, or you'll need a separate amp for the fronts. If you go the latter route, you should bridge 2 channels for each sub

zehnd

Thanks, I'll try the single sub. If I decide for two, I've got a older second amp I may be able to use.

jpk

I had a simmilar setup in my early car - Alpine head unit and a bazooka tube sub. At first, I was running all four 4x6 speakers of the front channels of the amp (using the external fader)
I then got a seperate amp (el-chepo $49 100w x2 amp from pep boys; in Canada it would be whatever they have at Canadian Tire or even Princess Auto) and hooked it up to the Alpine's subwoofer outputs and bridged into the bazooka tube; Also, I re-wired the rear speakers to the rear amp of the head unit.
The difference was night and day; The key being that the Alpine has a selectable crossover frequency and level for the sub output, so the 4x6's aren't trying to do the low frequencies. Even if you're just running the one sub, use the external amp; you'll be happy.