so i am hooking up the system in a week. i was looking at the amp and sub i have and i want to wire it right. it is a rockford fosgate amp punch 400s with two fosgate P3SD410 subs. they are 4 ohm subs. the amp output power ratings are 4ohm load 100 watts X 2, 2 ohm 200 X 2, or 4ohm bridge 400 watts X1. it is a four channel amp so i don't know how to bridge it to 1. the speaker lines are LF, RF, LR, RR. that is off the box. and on the back of the amp it says 50X4 at 4 ohms and 100X4 at 2 ohms. And the subs are dual voice coil. and the power handing watts are 300 RMS and 600 peak. can anyone help me out with this. and you lower the ohms of a 4 ohm to run it at 2 ohms with out hurting it. it shows a way to wire it at both 2 and 4. but how am i going to pull the power out of the amp. thanks

 

Why not get a mono amp? I have an alpine mrp-m450 amp that is 400 watts at 2 ohm for $110 shipped. Box and everything. It's less than three months used.

Here is a wiring diagram for the setup you are looking at
http://www.crutchfield.com/learningc...F4%2Dohm%5F4ch


Here is how you would do it with a mono amp
but you would need 2 ohm subs. don't know if you can wire 2 DVC subs with a 2 ohm load.
http://www.crutchfield.com/learningc...F4%2Dohm%5F4ch

Here are some wiring diagrams you can check out
http://www.crutchfield.com/learningc...rs_wiring.html

 

If the subs are 4 ohm DVC, about the best you can do with that amp is bridge it to 2 channel and run a sub on each bridged pair of channels. Wire each sub's voice coils in parallel and connect one sub to each bridged pair of channels on the amp. That will give a 2 ohm set-up on each channel. 200 watts RMS x2 into 2 ohms, and RF amps are always underrated. You cannot run that 4 channel to one channel.

In reality, 4 channel amps are not well suited for sub use, especially when bridging channels. Power supply issues are pretty normal. Just not designed for that application. I suggest using that amp for your "main" speakers and get a mono amp for your subs.

 

97F250!!!!!.......I havent seen you around here for a LOOOONG time, what have you been up too???

 

thanks man, that helped out alot. the subs are 4 ohms but the manual shows that it can be wired down to 2 ohm but what is up with the ohms if it is a 4 ohm sub but can run at 2 ohm. what is the difference between a 4 and a 2 ohm sub. i thought of just getting a mono amp. it is just that i just bought the truck and from my last setup from my sporttrac i had the 4 channel for my mids and highs and a 250 watts amp for my sub. and i have another RF amp from my wife old systems so i have three amp that i have to use just want to put them to use.

thanks

 

As far as I know, the benefit of getting to choose between a 4- or 2-Ohm sub is that if you have more flexibility in the amp you choose. For example, (2) 4-ohm DVC subs wired in parallel will put a 2-ohm load on 1 channel, whereas as (2) 2-ohm DVC subs wired in parallel would put a 1-ohm load on 1 channel. Most amps aren't necessarily stable at 1-ohm. Obviously, this math adds up the more subs you try to throw into the equation.

Someone feel free to chime in if I'm wrong, or if there are other benefits.

 

Hey Bartak1, what's up???

I'll avoid going into too many details about my absence, but the death of my brother in October put me in a bit of a tailspin, and somehow keeping up on the forums and such just didn't seem very important for quite a while. He suffered terribly with a brain tumor for 2 years. Puts a whole new spin on life in general and life in particular.

But I'm still into audio and I'll be around some.

Later!!

 

You ask a couple of good questions. Probably ones that others should ask before they detonate their equipment.

First of all, ohms are a measure of resistance to current flow. There has to be a certain amount of resistance to the current flow of the amp's output devices or they will burn themselves up(or the amp will go into protect/or both) trying to keep supplying the flow into a resistance that is too low. It's all about the design capabilities of the equipment.

Next, a 4 ohm sub can't be run at 2 ohms. What you have is not a 4 ohm sub. It is a dual voice coil sub with 4 ohms per voice coil. Huge difference. Connecting the two 4 ohm coils of one sub in parallel to get 2 ohms is the same to the amp as connecting two 4 ohm subs in parallel. The amp does not know the difference. The whole idea of dual voice coils is for flexibility of system design, but it' s hugely overrated. It can be useful, but it's not a necessity.

 

Im very sorry to hear that, my thoughts go out to you....