Added second sub and amp, no louder

[SteadyMobbin]

First post, but been following SMD Facebook and YouTube for a bit. Please correct me if I posted in the wrong area...

I just added a second amp and sub woofer that mirrors my original install exactly, but there is no perceivable difference in volume and the lowest bass notes are weaker. If I unplug either of the subs my overall volume stays the same and the lone sub seems to perform like it should. I am wondering if I am at some limitation from the vehicle's acoustics, or if the addition of the second amp is using all of my available power from the battery.

Original set up was a Polk 15 inch MM1540 4 ohm in a 1.5 cube sealed box (per spec) powered by a PPI 600.2 bridged at 4ohms clamp tested at about 480 watts, hooked up with OFC 8 gauge power wire.

New setup is 2 Polk MM1540's, both in separate 1.5 cube sealed boxes, both have their own PPI 600.2 bridged to 4ohms, 4 gauge ofc power wire split with D. block into 8ga. Ground is 8ga leaving amps into 4 ga with one ground point. RCA signal comes from Kenwood HU into first amp, and then output into second amp. Both subs are in phase with each other also.

I drive a Saturn Vue, and both subs face the rear with about 8-10 inches of space between them and the rear hatch. PPI amps are small and sit in cubbies under rear passengers.

Any help to get me louder is greatly appreciated.

[BboyTaktix]

do you have a spare battery or have you done the big 3 upgrade to your electrical system? do you also have a 4-channel amp pulling juice? If you are maxing out and pulling over 1000wRMS total then you are probably being limited by your car's electrical. Not sure what size your stock alternator is either. I don't see cancellation being an issue since they are both facing the rear of the trunk....

[SteadyMobbin]

I don't have a 4 channel amp hooked up, or any other accessories. Factory alternator is ~ 130 amps could be 120, and I only have a newer stock rated single battery under the hood.

I've added 2ga ground from the battery to the chassis, and from the battery to the engine. I've been hesitant to finish the Big 3 because my alternator positive wire runs into the vehicle wiring harness and then into the large fuse box under-hood before connecting to battery. I suppose I'm just scared to run the wire directly to the battery because the manufacture didn't do so and this is my daily driver.

[79 cutty]

upgrading that wire to ensure you can supply the amps with enough power should definitely help.

[Wicks]

Doubling power AND cone area should net you +6dB theoretically.

That should definitely be perceivable.

How's your voltage drop at the input to the amps?

[jarrius]

Keep the stock wire from your alt to your battery and just add the 2gague from the alt to the battery. Your not taking away you just adding

[Ben Fultz]

I believe the Saturn Vue has a 105 amp alternator. Most cars use around 40-50 amps to run the car and its accessory's. That leaves you around 60 amps, roughly 600 watts worth of alternator charging. If your clamp results are correct your around 400 watts over what your alternator can supply. I would guess its not louder due to the amps are starving from low voltage.

[goldeneye4564]

im assuming you have both amps gain matched already..

you could make a box for both subs...

... good, now that you want to make a new box, make it ported! and add another battery back there!

[BigManAC]

Yeah that wire will ensure you have sufficent power going to the amps. Are you running them off if a d block? Also welcome to the forum and its great to see another Saturn owner in here!

[notorious97200]

Not enough power to say it's an electrical problem.

Box problem.
You may have a cancellation issue.
Try to move the boxes around. Don't face them. They are very small for such big subs, but if you fire them both elsewhere, you can hear changes.

Be sure to have them in the SAME direction.

Good luck