I need some clarification on Series and Parallel

[Camry2000]

I understand the concept but I would like to know the results as in which setup is better for me and why.

OK Here is my setup. JL 300/2 and JL 12" W6v2 4ohm DVC.

I am running the 300/2 bridged and the specs say
Rated Power (bridged):
300 W RMS x 1 @ 3 ohm-8 ohm
(11V-14.5V)

Here is my question for best SQ, Should I run in Series 8 ohms or Parallel 2 ohms?

If 2ohms is better but the JL is not rated to run at 2ohms, would this damage the sub or amp?

[SilverRide]

Rule #1

NEVER run an amp at a lower impedance (ohms) than it`s rated at!
Yes, it`s possible you can damage your amp.

[kabal57]

If I understand correctly from the jl website, that amp will make 300x1 at any ohm load from 3-8 ohms? thats a new one to me. but anyway, if it does give 300 at say 4 ohms with as close to 14.4v as you can get, you'd be running pretty safe there.

I'm assuming you have only 1 sub? if so, I'd wire it series/parallel which will present the amp with a 4 ohm load. It may not give the full 300 watts, but it will be safer on the amp.
take the + from 1 coil and run it to the - on the 2nd coil, then hook up the left over + from one side and the leftover - from the other side and hook those to the corresponding +, - on the amp.
if that makes no sense, heres a site that may help as far as figuring impendance:

www.eatel.net/~amptech/elecdisc/spkrmlti.htm

If all else fails email the site admin and ask him about it, make sure you give all the specs on the speakers and amps
he emailed me back the same night I had a question for him.

[Camry2000]

Yes I only have one sub. The only way I can get this setup would be to add a second speaker terminal correct? That way I can run the amp in stereo mode and send 150 watts @ 4ohms to each voice coil.

http://www.eatel.net/~stentorian/elecdisc/spk1dvcn.gif

My other question is since the 300/2 can produce 300/watts between 3-8ohms, what is better SQ wise. Is it better to run at 4ohms or 8ohms? Power would be the same with both setups correct?

Currently I am running it in a series at 8ohms. I do have a 1 farad cap if that makes any difference. Thanks for your help so far.
http://www.eatel.net/~stentorian/elecdisc/spk1dvcs.gif

[J3adSeed]

i'd stick to 8 ohms. generally, the more ohms the better. decreasing the ohms will add distortion, even if its not much. the power will be the same no matter what on a jl audio amp (there are slight variations in real life, but in real life you're pushing closer to 400 watts anyway, all ohm and voltage loads are within 10 watts or so on a jl amp though). but one thing you'll notice is they don't say the distortion is always the same, they say its a certain amount at 4 ohms (if i'm not mistaken...). i think the more resistance you add the more control it has over the speaker, so just stick with 8 ohms, on a jl amp thats your best setup. also the capacitor will not change your sound at all, the only reason you'd need it is if your lights are dimming or something, because like they say, voltage doesn't matter w/ their amps. i have a jl 300/2 pushing subs temporarily and i have no dimming whatsoever, so i doubt you'd need a cap.

[Camry2000]

Koo thanks for the input.

I got a cap because my lights are dimming. The cap helped but it still dims if I crank it all the way up.

My Alpine HU is 60wx4 and my amp is 300watts, so I am running about 540watts, more since the JL pushes near 400watts. I may upgrade to a 500/1 amp later on.

[S|Lv3rBu||et]

quote: "i'd stick to 8 ohms. generally, the more ohms the better."

well man, I hate to burst your bubble, but that just aint so.
decreasing the impedance will produce a minimal amount of distortion due to the increased temerature that the amp is running at, however, as long as you stay above the minimum impedance of your amp (in your case 3 ohms), this distortion should stay within acceptible limits.

also, unless JL has found a way to break ohms law, it is not possible to deliver the same amount of power to a varying load at the same voltage. I think what the what spec you put down means is that the amp will deliver 300W at 11.0V into a 3ohm load. However, at an 8 ohm load, with 14.4 V, it will also deliver 300W. Only because the increase in voltage supply will compensate for the increase in impedance.

So, all in all, no... increased imedance (resistance, or ohms) WILL NOT give the amp more control over the speaker. The less impedance you have, the more easy it is for the amp to deliver the power to the speaker (because the speaker is offering less resistance to the power being put out by the amp).

What should you do in your setup? Well, if the minimum impedance on your JL amp is 3 ohms, wireing the two coils in parallel is out of the question, that would put you at two ohms and that could very well fry your amp. Wireing it like Kabal57 said will in fact present an 8 ohm load to a single channel of your amp... producing pretty much the minimum power output.... if thats what you want, go for it. It seems to me that the maximum power you could get out of this amp would be at 4 ohms (driving one coil), bridged. That would be pushing the most power through the least impedance therefore produing the most sonic output.

For more info on this topic, check out my post on "question on AMPS and SUBS"

[Camry2000]

S|Lv3rBu||et, what you said made sense. In a sense I think we are all trying to say the same thing but in different words.

I'll stick with 8 ohms as I do have a cap and do get 14.4 volts so I am not losing too much peak power. Anyway I will rather have SQ over SPL any old day. Thanks for your help guys.

[S|Lv3rBu||et]

Werd, SQ is #1.

But dB Arent bad either....
:thumbup:

[kabal57]

heh he is right, I goofed :/
Instead of doing series/parallel like i said above,
it should actually be one jumper from the - on 1 coil to the - on the other, and the same w the positives, and the leftover pos and neg to the amp
im a tard

[S|Lv3rBu||et]

Actually man, he would want to do that either, that would present a 2 ohm load and (from the specs he gave) could fry his JL amp. Even though it seems to me that most JL amps are 2 ohm stable, if his manual specifies 3 ohms minimum.... he shouldnt wire the coils in parallel like you described.

Like I said before, the best wireing for his setup is bridging both channels of the amp to one coil of the sub. The way he has it now (running the coils in series = 8 ohms) will work fine too, it will just result in less overall output given the same voltage supply.