Subwoofer wiring help

[Phillips_211 10+ year member]

Ok I have 4 rockford fosgate 10" S1 prime series subs, they rms at 150 and max at 300. I have a jl audio g1700 (JL Audio G Series G1700 Mono subwoofer amplifier — 700 watts RMS x 1 at 2 ohms at Crutchfield.com) specs here. The amp is a monoblock amp but has two positives and two negatives almost like a 2 channel amp. The subs are in one box that has two chambers (so two subs per chamber). Each chamber is about 1.5 cubic ft. I had the subs hooked up to the amp by just running 4 sets of positive and negative wires. 2 sets of wires were hooked up to one of the positive and negatives on the amp and the other 2 sets of wires were hooked up to the other positive and negative on the amp. They were pretty loud, but then I got to wondering how much louder they would be if i hooked them up like the rockfordfosgate website told me to to wire them down to 4 ohms (Rockford Fosgate® - R1S410). Once I hooked it up this way they subs were not anywhere near as loud as before. I know i can just switch it back but I would like a reasoning as to why it's not as loud, and if anyone has a better wiring setup i would really appreciate it.

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[sacsking916 5,000+ posts]

cause your not getting the same amount of power from a 1ohm as a 4ohm load

 

[Phillips_211 10+ year member]

cause your not getting the same amount of power from a 1ohm as a 4ohm load

The subs were never wired to 1me ohms? And the subs r wired to 41me ohms and they are not loud at all

 

[Z1NONLY 10+ year member]

Your original description;

4 sets of positive and negative wires. 2 sets of wires were hooked up to one of the positive and negatives on the amp and the other 2 sets of wires were hooked up to the other positive and negative on the amp.

^On a mono-block amp, that's 1 ohm. (Because electronically speaking, you connected all 4 positives together and all 4 negatives together.) That's 4 4-ohm subs connected in parallel and that's 1 ohm.

 

[THATpurpleKUSH 5,000+ posts]

Sounds like you could have went from 1 ohm to 16 ohms but that still doesnt sound right.

 

[Z1NONLY 10+ year member]

Your link just goes directly to the speaker on RF's website.

You were at 1 ohm. If you wired for 4 ohms, you should have much less power now.

I don't think your amp isn't rated for 1 ohm, so "much less power" is better than turning your amp into a blue-smoke generator with a 1 ohm load.

 

[dB-SPL 10+ year member]

That amp is only 2-ohm stable.. Check the specs. You only have two options of wiring those subs. Either 1 or 4 ohms and as previously stated by Z1.. All Pos to Pos and Neg to Neg is 1 ohm. Say for example every time your impedance (final ohm load) doubles, you get half the power you had before. So, you wired them UP to 4 ohms.. Not down. You might want to keep it that way unless you want to buy a different amp (which you should anyway 'cuz those subs are way under-powered).

EDIT: Just reread the amp specs. Not underpowered..

 

[THATpurpleKUSH 5,000+ posts]

If he is wired for a 1 ohm load, he is probably getting just enough box rise to keep the amp out of protect mode.

You can only wire one of 2 ways:

 

[dB-SPL 10+ year member]

Either

1) Run it at 4-ohms with little power

2) Run it at 1-ohm and risk frying it when you start crankin' on it

3) Buy another one of those same amps and run two subs to each amp at 2-ohms each

4) Buy a whole new amp that will do 600+watts rms at 1 or 4-ohms.

I think those are your only options..

 

[Phillips_211 10+ year member]

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not the best picture, but this is what i had first

I have two places to put +, and - Wires

 

[Z1NONLY 10+ year member]

On a mono-block amps, both +'s are electronically a single + and the same goes for both negatives.

They make them that way to simplify the connection of subs and manufacturing of the amp.

It would be a PITA to connect four 12 gauge conductors from two subs to two holes on an amp. And since most manufactures have a few 2ch amps in their lineup, the connection point for "two positives and two negatives" are already in their proverbial parts bin.

So they bridge the connections internally, use the end plate(s) from the same two channel amp, complete with RCA's and/or power connections, some different amp guts and maybe even a different size casing and TA-DA!

They have a mono block amp with two +'s and two -'s