Is this the best way to wire this system?

[cgorman21]

I have an Alpine CDE143BT head unit, a Rockford Fosgate P400-4 4 channel amp, and 2 8" JBL GTO804 (4 ohm) subs. I have a set of speakers wired to the front channels. I bridged the rear for the subs. I connect the positive and negative from the bridged ports on the amp to the positive and negative terminals on sub 1, then connected the positive on sub 1 to positive on sub 2 and negative on sub 1 to negative on sub 2. It looks like pictured below . Is this the best way to wire them? My setup looks awesome, but I have not wired a system before and don't know the best way to do it with my equipment. Thanks for your help in advance.

View attachment 26544071View attachment 26544072View attachment 26544073

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[naughtyca 10+ year member]

that 4 channel amp is bridgeable i would bridge the 2 channel to one sub since your sub is 4 ohms

Four-channel amplifier delivers 50W x 4 @ 4-Ohms, 100W x 4 @ 2-Ohms, 200W x 2 @ 4-Ohms bridged RMS

 

[naughtyca 10+ year member]

Double post

 

[cgorman21]

I don't know how to delete the other one, started a new thread as you suggested. Sorry I am new here, just looking for a little help.

 

[naughtyca 10+ year member]

you are good, i accidentally did a double post lol, did you understand what i said to bridge your 2 channels pretty much making the amp 2 channel instead of 4 channels

 

[Jepalan]

The OP already said he was bridging the amp into the two subs in parallel. This is not good. This amp is not 2-ohm rated when bridged.

by wiring two x 4 ohm subs in parallel you have created a 2-ohm load on the bridged amp output. Your amp is only spec'd for a 4-ohm load when bridged, so you are likely overloading it this way and could blow the amp.

Your subs cannot be wired in an ideal way for this amp. The most foolproof way to run them is to wire them in series to the bridged output. The 8-ohm load wont get as loud but the amp wont blow either

 

[naughtyca 10+ year member]

the amp is stable on 2 ohms but he will get most wattage by bridging the 2 channel

50 watts RMS x 4 at 4 ohms (100 watts RMS x 4 at 2 ohms)

200 watts RMS x 2 at 4 ohms (4-ohm stable in bridged mode)

 

[Jepalan]

the amp is stable on 2 ohms but he will get most wattage by bridging the 2 channel50 watts RMS x 4 at 4 ohms (100 watts RMS x 4 at 2 ohms)

200 watts RMS x 2 at 4 ohms (4-ohm stable in bridged mode)

Nope. You are giving the OP bad advice that may blow his amp. The RF P400-4 is NOT rated for 2-ohms BRIDGED. Check the manual please. When bridged "minimum load impedance is 4 OHMS". Check the spec and manual here:Rockford Fosgate Punch P400-4 4-channel car amplifier 50 watts RMS x 4 at Crutchfield.com

If he wants to bridge the amp he should wire the speakers in SERIES to 8 OHMS load.

Note: he has TWO 4-ohm subs. There is no way to wire two 4-ohm subs and get a single 4-ohm load.

 

[bbeljefe]

↑↑ This is correct.

When you bridge a two channel amp, you are introducing half of the total load to each of two channels. So, an amp that is only stable at 2 ohms in stereo can only be bridged to see a 4 ohm load. This four ohm load equals 2 ohms per channel, which is the lowest impedance this amplifier can handle per channel.

The way you have it wired now, OP, is causing the amplifier to see 1 ohm per channel, which is too low for that amp. Do like Jep said and wire the woofers in series. Either that or find yourself some two ohm woofers and wire them in series for a total of a four ohm load on the amplifier. That way you'll be able to get as much out of the amp as possible.

However.... I've used those GTO 8's before and they sound very good on low power. They'll also take a **** load more power than they're rated for but your amp won't like what you've got now.

 

[naughtyca 10+ year member]

Nope. You are giving the OP bad advice that may blow his amp. The RF P400-4 is NOT rated for 2-ohms BRIDGED. Check the manual please. When bridged "minimum load impedance is 4 OHMS". Check the spec and manual here:Rockford Fosgate Punch P400-4 4-channel car amplifier 50 watts RMS x 4 at Crutchfield.com
If he wants to bridge the amp he should wire the speakers in SERIES to 8 OHMS load.

Note: he has TWO 4-ohm subs. There is no way to wire two 4-ohm subs and get a single 4-ohm load.

look at what i wrote, bridge the 2 channel to 1 channel for 4ohm per sub, his sub is single voice coil 4 ohm. so his total impedance per sub is 4 ohm which will yield 200 watts per sub at 4 ohms

 

[Jepalan]

look at what i wrote, bridge the 2 channel to 1 channel for 4ohm per sub, his sub is single voice coil 4 ohm. so his total impedance per sub is 4 ohm which will yield 200 watts per sub at 4 ohms

Read what the OP wrote -> "I have a set of speakers wired to the front channels."

With your advice he will have two kick-a$$ sounding subs and no front speakers, so you didn't really answer his question.

That said - you are correct. I missed your point about using all four channels of the amp and bridging to the speakers individually. That will work with no harm to amp, but as above, he will need another amp for his fronts. He asked how to wire the system he has.

Sorry about the amp blowing comment though.

 

[naughtyca 10+ year member]

that is correct he will need to get another amp for either the sub or the door speakers.

OP if you decide to get a new amp i would suggest to get a decent powerful sub amp and use this RF for your doors, so if you decided to upgrade your subs it will be less expensive.

 

[naughtyca 10+ year member]

that is correct he will need to get another amp for either the sub or the door speakers.

OP if you decide to get a new amp i would suggest to get a decent powerful sub amp and use this RF for your doors, so if you decided to upgrade your subs it will be less expensive.

 

[cgorman21]

Thanks for your help guys. If I get another amp for just the subs and use the RF for both sets of speakers what should I be looking for as far as power/specs? I appreciate the advice.

 

[cgorman21]

Also, i only have 2 pre amp rca outs, how would i got about connecting two amps with 3 sets of inputs?