Help with Sub Selection (Leenjen)

[sirhk100]

I'm looking over the book for my amp and here's the info I have to go with. I'm looking for a single 12" sub. My amp test sheet says it's putting out 225W/channel tested at 2 OHM. Does this mean they tested it with a 2 ohm resistor on each channel? I also think that's a max rating because in the book for the amp it's saying it's RMS is 100W/channel with a 2ohm load. Here's wher my questions start. I've got a couple options, I think. The manual says that I can run a two 2ohm speakers and push 100RMS to each or bridge it and run a 4ohm minimum sub at 200watts. Does this mean I could run a 2ohm DVC sub and run one channel to each set of leads on the sub? I'm always confused on this ohms thing and don't want to kill my amp. Here's the direct wording from the book.

RMS continuous power per channel both channels driven into a 2ohm load from 20 to 20,000Hz with less thean .1% THD = 100Watts

RMS continuous power mono into a 4ohm load from 20 to 20,000Hz with less thean .1% THD = 100Watts

Also on the wiring diagrams it says that if I'm running 2 subs wired normal to run 2ohm MINIMUM and if I'm bridged run one 4ohm MINIMUM sub.

Basically what options for subs do I have. If I have to run just a normal 4ohm sub bridged I'm leaning towards a Fosgate RFP3412. Can I run a DVC sub with 1 channel going to each set of leads? If so, what Ohm rating does the DVC sub have to hav minimum to keep from killing my amp? If I can run a DVC wired like this I'm looking at going with a JL or Fosgate sub preferably no more then $150. Thanks for the answers to my many questions!! If some one can give a quick tutorial to how Ohms are changed with bridging and DVC subs etc... that would be great. I have the Amp book in front of me so if you need any more info please ask!!
Khris

 

[leenjen]

the best way to run a subwoofer with Dual 2 ohm voice coils is to run the coils in series to create a 4 ohm mono load.

 

[Flyhalf]

anyone care to fully exaplin the whole ohm's thing?

thanks

 

[ChuckyD]

2 WORDS:
KICKER SOLOBARIC!!!!!!!!!!!!!!!!!!

 

[brent239]

an ohm is basically a load on the amp. when you bridge an amp you create a 2 ohm load, what everybody considers 4 ohm mono. if you ran a 2 ohm dvc with each channel running a coil then your amp is pushing a 2 ohm load. if you run one 4 ohm svc bridged you are making the same amount of power. the reason the make 2 ohm dvc is to pull serious power from stable amps. if you run a 4 ohm dvc with your amp bridged to each voice coil your amp is runnning a 1 ohm load, which I did with two 4 ohm subs and the punch 60, which is very similar to your amp but smaller, and the amp had no problem at all. rockford makes a solid amp and my professional opinion you shouldn't have any problems. however if you slam it alot and have your amp gains cranked up, then dont do it, thats too much of a risk. but a solid setup would be a single 4 ohm and youll be set. let me know if you have anymore questions

 

[leenjen]

Originally posted by brent239
if you run a 4 ohm dvc with your amp bridged to each voice coil your amp is runnning a 1 ohm load, which I did with two 4 ohm subs and the punch 60, which is very similar to your amp but smaller, and the amp had no problem at all

dual 4 ohm voice coils can't possibly create a 1 ohm load.
parallel will give you a 2 ohm load, and series will give you an 8 ohm load. just like two 4 ohm SVC subs will create a 2 ohm mono load in parallel, and an 8 ohm mono load in series. until last week i was running four 15" SVC (4 ohm) in parallel to create a 1 ohm mono load.
i am gutting my current system and i sold two of them, so now i am running two in parallel @ 2 ohms mono.

my next subwoofer will have dual 2 ohm voice coils, and i am going to wire it in parallel to create a 1 ohm mono load (series would make it 4 ohms mono).

 

[brent239]

you are right leenjen. I'm sorry you must have misunderstood. with the setup you explained with the four 15's into a one ohm mono load, you are right that is one ohm mono which is making your amp run at a .5 ohm stereo load. when you bridge a sub your power doubles b/c it dropped it your ohms by half.