jawzforlife1

I have two Rockford Fosgate XCL 12" subs (RMS 500 watts, max 1000 watts, if I remember correctly) and I also have 2 rockford amps a 500 watt and a 250 watt (both 4ohm if I remember). What would be the best way hook my subs to my amp. I've done some diagrams but if there is a better one than I've shown please let me know.
I also have some standard rockford punch 12" subs put that really doesnt matter.

si_camaro

You won't see much difference between diagrams 2 and 4, you'll either have 1 sub at 500w or 2 at 250w each. No real difference as they'll be mono. Diagram 5 might be interesting, Personally I would save that 250w amp for powering the 6x9s or equivalent speakers you have for the midrange and bass. 1 would work, but subs work best if they're bridged in mono. 3 wouldn't be a good idea as everything is 4 ohm and wiring them in series will double the impedance to 8 ohm and they won't put out as much.

To summarise, I would do number 2.

82berlinetta350

I'd say that running them at 8ohms on bridged would be your best bet. If I remember right, your am will still be pushing the same at 8ohms as if there were a 4ohm load when it's bridged. That's just my ramblings. But I'd say go with wiring them in series in bridged mode.

jawzforlife1

so #2 is "bridged". Is each speaker still at 4 ohms each in #2 is is it dropped to 2 ohms each

82berlinetta350

By running them as shown in #2, you'd be running at 2 ohms, and more likely to fry something. By running them like #3, they'd still be getting the amount of power the amp is rated for in bridged.

si_camaro

You won't fry anything if the amplifier is 2 ohm stable, which most are nowadays. Running them in series like in #3 will indeed push the impedance up to 8 ohm which will not allow them to run at their full potential.

Eric86TA

Is the 500w amp a two channel output amp? If so, you need to consider what each channel is seeing. In #3 the over all load is 8ohm but it is bridged across two channels. In that case, each channel sees a 4 ohm load. If you hook the subs up in parallel then the over all load is 2 ohm and each channel is going to see a 1ohm load on it. That is why you see amps list a (for example) 2ohm max load and then a 4ohm max load bridged. If the amp is a mono block then you don't have to worry about it but your diagrams show a two channel amp.

Eric86TA

Basically, if your amp isn't 1ohm stable the either #1 or #3 is your best bet and there is no difference between the two except for ease of installion. Personally I would run each channel on its own sub. That way if you have problems later, you can take one out and still play the other one without having to rewire the whole thing. IMO.

jawzforlife1

its is a 2 channel amp. And I dont have to worry about if 1 sub gose back and rewiring, Its not that had to run a wire fom the sub to the amp.

I think I'm just going to do the one sub with the 500 amp. That way I save alot space in the back of the car. And I can send all the power of my amp to one sub and the ohms will be safe.

What do you think.

82berlinetta350

The fact that the amp is a two channel is where the problem with 2 ohms comes in. You can run the channels themselves at 2 ohms. But most amps cannot handle 2 ohms bridged for very long. I tried it before. And about them not running full potential. That's crap, I ran dvc's in series bridged, and they worked loads better than running them on seperate channels. It's the fact that the amp sees a 4 ohm load even if the impedance is 4, 8, 16. It's the fact that you're connecting the ouput of the 2 channels.

Boxeat2469

1 and 3 are basically the same. Option 2 would be the best, but only if the amp is stable at 1 ohm. I would definitely try to utilize both subs. Doubling the power is worth a 3 db gain, but doubling the number of speakers is a 6 db gain.

Eric86TA

How exactly does the amp see a 4 ohm load even if the impedance is 4, 8, or 16 ohms. If I could make that happen, I would be a rich man. Am I misunderstanding your statement. If the load is 4 then each channel sees 2. If the load is 8, each channel sees 4, and if the load is 16, each channel sees 8.

82berlinetta350

What I was trying to say, is that when the amp is running in bridged, it is going to see a 4 ohm load, unless you go to a higher resistance. Therefore, if you run 2 - 4 ohm subs in series, bridged on the amp, you're going to be running at what the amps brdige rating is. Regardless of wether you're running at 8 ohms or 4. If you run at 2 ohms on bridged however, you're going to be heating the amp up too quickly, because the resistance is going to be higher, and it is pushing out more power. I've tried running below 4 ohms in bridged, and it doesn't take long to either set off the thermal protection, or blow the amp. I did however, just hook up a set of 4 ohm dvc subs to a 4 channel amp. And the subs hit a lot harder, and the amp stays cooler, if you run in series on bridged.

AJ_92RS

Once again Eric's right (as in a previous thread. It must be that "Blue Grass" ).

#1 and #3 will give you the same output as far as watts. #1 would be better if you had each sub in seperate enclosers (or divided). #3 is better for one enclosure for both subs (or undivided).

The reason for #1; Even though most bass in music is recorded in mono format, some digitally recorded CD's have bass in stereo. By using seperate enclosures, you won't have to worry about one sub fighting the different frequencies of the other if they're not reproducing the exact same sound. The other reason is (as Eric said) if you blow one sub, then you just unhook it (and can even take it out) and you still have another sub in the proper size enclosure to run all the amp's power to.

The reason for #3; Regardless of how the music's recorded, you'll always have mono sound going to both subs in equal amounts. If you do blow one though, you'll have to replace it right away because if you take it out, you'll just have a big hole there. If you unhook one and leave it in the box, you'll not only double the size of enclosure the single sub uses, you'll increase the area even more because the dead sub will act as a passive radiator. That would sound awful.

#2 will hurt the amp if it's not able to handle a 2 ohm load while bridged. If it can handle it, then you'll get the most power (watts) and the highest SPL (loudness).

#4 is fine if you only want one sub. I only have one, and I'm happy with it. *shrug*

#5 is pointless. You'll barely hear the sub with the 250 watt amp (if at all) unless you cross it over at a higher frequency range (i.e. bandpass) than the one with 500 watts. However, even that doesn't work well unless the higher frequencies are sent to a smaller sub like an 6", 8", or 10" If you were to use 12" for both, then they would certainly need seperate enclosures and I would recommend a smaller one for the higher frequencies.

Eric86TA

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trans_am_ta_84

ok so while we're on the subject i have 2 mtx thunder 6000 12". so their 4ohmz each. my amp is a pyrimid 1400watt amp which is 2 ohmz, so which diagram would be the best setup for my speakers? i just used number 1 but now i see all these choices?

AJ_92RS

Unless your amp is stable at 2 ohms bridged (which I doubt with a Pyramid), number 1 and 3 are your only options.

Some amps that are labelled "Sub amps" or "Bass amps", or even higher priced amps that advertise that stuff can run 2 ohms bridged, but they're not cheap, nor are there lot made.

Night Hawk

I have a JBL 600.1 sub amp. It says it will push 300w @ 4 ohms and 600w @ 2 ohms.

Does anybody know if this amp is 2 ohm stable bridged? Would diagram #2 be my best bet? Right now it is hooked up like in diagram #1.

The subs are Kicker Solobaric 4 ohm subs.

Eric86TA

The specs say that the amp is 1ohm stable but 2ohm optimized. You can run diagram #2 if you want to. It will give you the most power but I suspect the 2ohm optimal means that there is quite a bit more distortion at 1 ohm. Personally I would leave it like you have it. IMO.