Need help on sub wiring

[twofoolish2b 10+ year member]

Hey guys, I need some help on wiring my sub. It is a Memphis Power Reference dual voice coil 4ohm sub. I'm trying to wire it for a 4 ohm load. I called crutchfield and asked could it be done and they said it can only be done in either a 2ohm load or a 8ohm load. The guy said I would need a 2ohm dual voice coil sub to be able to wire it at a 4ohm load. Is that true or what? How can I get a 4ohm load from a 4ohm dual voice coil sub? What would happen if I run it at a 8ohm load or what would happen if I only ran one voice coil? Please help.

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[jeeper07 5,000+ posts]

whoa first of all yes they are right second of all why do you want to run it at a 4 ohm load ??

 

[twofoolish2b 10+ year member]

Well the amp I'm using is a USAmps I/S 4085 4 channel amp. I'm going to bridge two channels for the sub but the manual says for bridge it is 270wx2 @4ohms. Do you think the amp can do a 2ohm load or I shouldh't try it? Also I thought the dual voice coil made it easier to wire is why I went with it to start, now I'm all confused. lol What's the best thing I can do?

 

[Prowler573 5,000+ posts]

Whatever CS representative you spoke to at Crutchfield was entirely correct. If you have a DVC 4 Ohm subwoofer your only available options are wiring the coils in parallel to a 2 Ohm final load like this:

OR

wiring the coils in series to an 8 Ohm final load like this:

The guy said I would need a 2ohm dual voice coil sub to be able to wire it at a 4ohm load. Is that true or what?

Absolutely correct.

How can I get a 4ohm load from a 4ohm dual voice coil sub?

You can't is the plain truth. It just simply will not happen.

What would happen if I run it at a 8ohm load

Your sub would see approximately half of the amp's rated 4 Ohm load output. In your case, being that the amp is rated for 270w X 2 @ 4 Ohms mono bridged if you were to present that bridged output channel with an 8 Ohm load you would be sending around 135w (give or take) to it.

or what would happen if I only ran one voice coil?

To tell you the truth I do not know for certain but I wouldn't advise it. Hopefully someone with a bit more technical knowledge than I have will pop in and address that last question.

 

[twofoolish2b 10+ year member]

Ok tell me will this work or not. Lets say I don't bridge the 2 channels for the sub but I just ran 1 channel to each voice coil? The amp is is stable at 2ohms at 135wx4 channels. Could something like that work?

 

[Prowler573 5,000+ posts]

Ok tell me will this work or not. Lets say I don't bridge the 2 channels for the sub but I just ran 1 channel to each voice coil? The amp is is stable at 2ohms at 135wx4 channels. Could something like that work?

Your sub has 4 Ohm voice coils.

If you wire each channel to its own amp channel you'll be showing those two amp channels a 4 Ohm load which is what....like 85 or 90 watts or so? You'll still be feeding the sub less than 200w which won't be nearly enough to get the full potential of the driver to come and play //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[twofoolish2b 10+ year member]

I think I see what you're saying. You're saying each voice coil on the sub is looking for 250w and if I only send 135w to each voice coil it would still only see 135w and not the 135w x 2 which would be 270w which is what I was thinking it would see?

 

[Prowler573 5,000+ posts]

Let's start here...

I am not familiar with the Memphis gear. What is the RMS input rating for that sub?

 

[Prowler573 5,000+ posts]

I gotta go run an errand....if this is still unresolved when I get back in an hour or so I'll be happy to pick up where I left off....

 

[twofoolish2b 10+ year member]

The RMS on that sub is 250w, the MAX is 500w.

 

[mikeyboc 10+ year member]

The RMS on that sub is 250w, the MAX is 500w.

The 250 is for both coils, not just one. If you bought the sub from Crutchfield, why not return it and get the 2 ohm DVC?

 

[twofoolish2b 10+ year member]

I didn't get the sub at Crutchfield, I got it at WoofersEtc. I have no problem with sending it back or even if I have to buy another sub. I was just trying to get everything hooked up over the weekend but now it looks like I'm not gonna be able to. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[mikeyboc 10+ year member]

I didn't get the sub at Crutchfield, I got it at WoofersEtc. I have no problem with sending it back or even if I have to buy another sub. I was just trying to get everything hooked up over the weekend but now it looks like I'm not gonna be able to. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

I think it will be easiest to either A) get a different dual 2 sub or B) get a seperate amp for the sub (make sure it puts out the power you need a t 2 ohms for the sub you have.) You could probably find an amp that puts out 250-300 @ 2 ohms for a good price.

 

[twofoolish2b 10+ year member]

Thanks for everything so far. Lets say I wanted to just keep the same amp and bridge it to a single channel at a 4ohm load. Would a single 4ohm voice coil sub work for what I'm trying to do? Something like this is what I'm talking about.

Also just to make sure that the sub will work this time tell me if this sub will do what I'm trying to do. http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=2143

 

[mikeyboc 10+ year member]

Thanks for everything so far. Lets say I wanted to just keep the same amp and bridge it to a single channel at a 4ohm load. Would a single 4ohm voice coil sub work for what I'm trying to do? Something like this is what I'm talking about.

Also just to make sure that the sub will work this time tell me if this sub will do what I'm trying to do. http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=2143

Single 4 ohm will work, or a 2 ohm dvc as stated before.