Sub wiring

Alright, a question that is a bit off the beaten path. Tried doing some Googling, but didn't get a good answer, so here goes....

I have an Solobaric S8L7 with dual 2 ohm voice coils, the amp that I am using for the sub is a Rockford 400.4 (100x4@4ohms or 200x2@4ohms). The front and back channels on the amp can be bridged, but they cannot be bridged across all 4 channels, i.e. I can't bridge it such that there is one output for the entire amp. As such, I have wired each voice coil on the sub to one of the bridged channels on the amp in order to get the entire power output of the amp to the sub.

I am having some problems getting the sub tuned so I am wondering if wiring each coil to an amp channel is not "acceptable". Any input?

The amp is 2 ohm stable btw.

 

Each one of your subwoofer's voice coils are 2ohms.

You stated that your amp can be bridged down to 2channels making 200x2@4ohms.

You're attempting to bridge them just like that but at 2ohms which is a big no no. I'm sure your amp is 2ohm stable but it's not likely 2ohm stable when bridged.

 

Understand, but I don't push it that hard. Would this setup cause problems in tuning the crossover? If I set the crossovers (lt and rt channels) to 80, I get very little output. If I raise that to 125, I get reasonable sub output. If I raise it to 250, it starts repetative "thumping". Was not expecting these results for a crossover setting.

Setting gains and/or bass enhancement has the expected results.

 

Was considering wiring the sub back up to 4 ohms and running it off just one channel to see if that changes anything. Sounds like I may need to do that anyway.

 

One more curiousity question, what happens when a dual voice coil sub is wired with only one voice coil powered?

 

Good idea

Wire both coils

 

Yeah, yeah, I know, but I was just curious what happens to a dual voice coil sub when only one coil is wired up? Acts the same, dead coil is a drag on the active coil, damages the sub, universe collapses, dogs dating cats,,,,,

Just a thought exercise.

 

Was also trying to see if anyone could explain the results I was getting, as they just don't make sense to me.

 

It wont damage it as far as I know. It just wont really work quite right.

I don't really have an explanation really. My guess is that the amp was protecting itself from putting out the power it would need to play the lower frequencies and overloading itself. But I really have no idea.

 

Thanks for the opinions and input, appreciate it.

Anyone else?

 

you need to have an amp made for a sub. trying to run 2 channels to a sub is bad, you need either a mono amp or a briged two channel, that is what i have in my truck.

trying to wire it to 4ohms then running it, you will not get proper sound out of the sub, as trying to run two channels to it bridged. and dont use the sub as a bridge, you will blow it up eventually and, as you said, it just doesnt act right.

 

^You can run a 4 channel amp on a DVC sub no problem. Not sure where you heard that. It would be simpler with a mono amp but it's not necessity.

 

Exactly. I'm running a 4 channel amp. The front channels run my components and my back channels are bridged to power my DVC sub.

 

Not quite my situation though. I have a 4 channel amp, which is bridgable for either, or both, of the front channels or rear channels, but not bridgable to a single channel with all the amp's power. I have the front channels bridged and feeding one of the voice coils, while the other channel is bridged and feeding the other voice coil.

I haven't seen a vendor config document that states feeding each voice coil from an independant amp channel (although the same sonic content, due to a single RCA feed) is an approved configuration.

Would have thought it would work out ok assuming that both channels are set the same for gains, crossovers and any bass boost. ItalianS has a point about it actually being 2 ohm stable when in briged mode though. Docs don't specifically say one way or the other on that.

I am going to rig the sub back up for 4 ohm, and run that off of one brigded amp channel and see what happens.

 

Most aren't 2ohm stable when bridged. It's rare that they are.

 

Fully understand your point, just hadn't seen that statement before. As soon as I re-configure my setup, I'll feedback. Again, thanks for the input.

 

I did find this reference to 2 ohm stable on the Rockford website for a Rockford T400-4:

Rated Power
(RMS Continuous Power)60 Watts x 4 @ 4-Ohms
100 Watts x 4 @ 2-Ohms
200 Watts x 2 @ 4-Ohms Bridged
2-Ohms x 2 Bridged Stable

 

OK, so I wired the sub back up for 4 ohm load and attached it to the rear bridged channels of the amp. Everything worked fine and I could tune as expected. So either it wasn't 2 ohm stable in briged mode, or it was having a problem with independant amp channels feeding each voice coil.

It's working fine now, so I'm done. Thanks for everyone's input.

 

Glad to hear it man. Enjoy the sub!

 

Like I said it's all working great now. I hooked my front components into the front channels on this amp and it was so much easier tuning the entire setup thru one amp.

Still bugs my as to what the actual problem was though. I did some more searching and it appears that this amp, Rockford T400-4,

http://www.crutchfield.com/s_575T4004P/Rockford-Fosgate-Power-T400-4.html?tp=115

IS documented to be 2 ohm stable when in bridged mode. Crutchfield even has it documented that way. So definitely not clear on what the real problem was/is.....