I have a two channel amp that is 300 watts at 4 ohms, bridged. I need to connect it to a duel 4 ohm subwoofer. How does it need to be wired to keep a 4 ohm load on the amplifier?

 

You can only run that subwoofer at an 8ohm or a 2ohm load unless you want to put 1 voice coil per channel which would not be bridged.

 

No 4ohm load possible, with the exception of running only 1 voice coil, which you really don't want to do. Also do not run one voice coil to one channel and the other to the other channel. The voice coils need to see the same exact signal at the same time, this is why you run them both off of one channel or both with the amp bridged to one channel.

You can run the voice coils from different channels if you have an amp with balanced inputs. If they are not balanced inputs then the voice coils will be in essence fighting one another.

So your options are:
1) run sub in 2ohms off of one channel
2) run sub in 2ohms with amp bridged to one channel. Sounds like your amp is probably not rated to handle this and this could damage the amp.
3) run sub in 8ohms with amp bridged to one channel. This may be your best option depending on the RMS of your sub and what your amp puts out.
4) Buy a new amp that is able to run 2ohms mono
5) Buy another dual 4ohm sub (same kind as what you have now) to get a 4ohm load at amp, each sub at 2ohms.
6) I know that Fosgate use to make a “pot” that you put inline between your amp and your speakers that would allow you to in essence dial in your desired resistance you wanted your amp to see. I didn’t see these take off that much because amps now a days are capable to run 2ohms, 1ohm, or 1/2ohm mono.

 

My sub has a 300 watt RMS. So, will #1 or #3 keep 300 watts going to my sub, while keeping a 4 ohm overall load on the amp? I only want to use one sub.(Sorry for the dumb question, I have very little knowledge about this stuff)

 

You will not be able to get the 300 watts out of the amp if that is the bridged rating. If you list the amp, maybe we can be more specific. Reese is correct in that you do not want to hook one coil to each channel but, only if you are sending it a stereo signal. If your head unit has a subwoofer output, you can use it. If it has one output, ie...one rca, then run a y adapter from it to each amp channel. This would give both channels the same sub signal. But, you are still only going to get whatever power your amp does at 4 ohm stereo.

 

Thanks for the input, guys. Sounds like with my experience level, I'm better off to get rid of the v2 D4, and go ahead and get a 12W3v3 - S4.

 

what is the amp????

 

Well it all depends on what you want to spend your money on. I would try hooking your sub up at 8ohms with your amp bridged to mono. Also post what amp you got.

You have a trade off if you want to either get a new sub or amp. I would opt to get a new amp especially if your current one doesn't have a level **** that you can mount up front (this is a **** that allows you to adjust how much bass you have) and if it is not a classd or classbd amp (these are more efficient amps and are designed to run subs). Also you can pick up some nice 5 channel amps (with sub channel classd) that allow you to run your entire system off one amp for a good price. This might also give you some more adjustments for your mids/highs, depending on what you are doing there.

But if your sub is old and has been used a lot then it might be better to get a sub to match your amp. Again it all depends on what you want to spend your money on. I would still try hooking up the sub at 8ohms and seeing how this will sound. Your amp will only put out about 150watts and your JL sub should be fine at this power. You would probably need to make some adjustments on your gain to the sub amp and the one to your highs/mids (if you are running one to them as well). This way no money spent.

 

It's a RF 3002.

Yeah, I bought the sub from one of my buddies. I have another friend that's willing to give me just about what I paid for it, so I'm really not going to be out any money by getting rid of it (I want to get the full 300 RMS since I'm only going to run a single sub). And the amp is almost brand new. So with that being said, I guess I'll go with the new sub instead of a new amp. Plus, I'll have a v3 instead of a v2, even though I don't know how much better they sound.