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Discussion Starter · #1 ·
So I have 2 jl audio w3 12" subs. I bought a package (with a crappy amp). On the side of the box it says 2 ohm. I think the amp is 4 ohm. The subs rms is 300 max each, so 600 for the pair. I was looking for a 2 ohm stable mono amp putting out around 600 rms.

I go to the audio store to see what they have. Guy tells me is (2) 4 ohm subs are wired in series (not sure what mine are, bought em used) that I will need a 1 ohm stable amp? He also thought i would be okay with a 600 rms amp for 150-300 rms subs, so he could be wrong.
 

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If your subs are 2 ohm subs and they are wired together you will either have 4 ohms at the terminal, or 1 ohm. If they are 4 ohm subs and they are wired together you will have either 8 ohms or 2 ohms at the terminal, all depending on how they are wired up (series vs parallel). You need to take an multimeter and test what the ohm load is at the terminal (if you have one terminal), if it's 8 ohms with both subs wired up (to one terminal) it needs to be rewired down to 2 ohms ( or if it's 4 ohms at each terminal than twist the positive connection and negative connection together and you should have 2 ohms) and you need a mono block amp stable at 2 ohms which isn't hard to find, you can pick one up on C-List in your power range for pretty cheap (600 watts is a good rms rating for two 300 watt subs together). If it's 4 ohms with both subs wired up (at one terminal) than you'll want to find a two channel power amp that fits your needs. Not to hard but it's gonna take a little more searching. With the two channel you're gonna want to look at the "bridged" power output since that's what you'll be doing, bridging down the two channels into one to run the subs.

Hope this helps?
 

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Discussion Starter · #3 ·
Yeah it does. Right now I have one of those cheap flea market amps that claims its 1000w x2. If i turn the music up, even at low gain, the amp goes into protect mode. And Im almost positive the subs are at 2 ohm and the amp is 4. Ithink the subs are in parallel (2 ohm) and series would make them 8 ohm. Just wanted some clarification, Thanks.
 

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Yeah there are a lot of bs amps out there that have HUGE numbers stamped or painted on the cases. When there RMS rating is maybe 1/4 that. But yeah if you've got 2 ohms with your subs "bridged" (wired together with + and -) than your best "bang for your buck" will be a mono block amp. One with a 300 watt 4 ohm rms rating, because at 2 ohms it will put out damn near double that.
 

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Discussion Starter · #5 ·
Ok, just had a thought.

So I have (2) 4 ohm subs. 300 rms each, 600 rms total.

They are parallel so now they are at 2 ohm.

Does my rms change? Would my amp have to be 300 rms @ 2 ohm, 600, or 1200?
 

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What you want to do is pop one out & confirm it's identity. The cheap amp is probly going into protect due to circuit mismatch (amp not seeing the ohm load it's set for).

Once you have a positive ID of the specific model you have ;12W3v2-D2, 12W3v2-D4, 12W3v2-D6. Dx stands for Dual voice coils, each being of x ohms i.e. Dual 2ohm/4ohm/6ohm. Then you need to go here -> mobile.jlaudio.com/pdfs/12w3v2_MAN.pdf (the manual to that line of subs) & double check the wiring job. Use the factory jlaudio wiring plan (series or parallel) & get an amp that will match that ohm load.

~psguardian
 

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It's not that complicated, you're only gonna have limited options of ohm load coming out of a bridged terminal.

To answer your Q, no your RMS wattage you subs can handle doesn't change depending on how you wire it up. What changes is the resistance they put on the amp. So for you, and your situation you're going to want to focus on the RMS wattage an amp put's out on a 2 ohm load. So...that's why I say look for a mono D class amp that is stable at 2 ohms and put's out 300 watts or so at 4 ohms (because usually the RMS wattage will damn near double on a 2 ohm load). I run an Alpine Type R DVC 10, so I have a 2 ohm load with my voice coils bridged. I have an Alpine MRP-M650 pushing that Type-R, my amp puts out 400 watts on a 4 ohm load, and 600 watts on a 2 ohm load. So my sub is getting more than enough power at 600 watts to run efficiently, and loud.
 

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Discussion Starter · #8 ·
Ok well the subs are 12 w3d4 so they are the OLD ones, dvc and are 4 ohm. So with two, i am pretty sure that i can wire them either at 1 or 4 ohm only and not 2 (what ive read)
 

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Ok with dual 4ohm voice coils you can either get 2ohms on a sub our 8ohms on a sub, then you have to "bridge" that down for a mono amp to either 1 ohm by bridging the 2...2ohm subs together or 4ohms when bridging the 2...8ohm subs together or run each on a separate channel on a 2 channel amp (not recommended). What I would do is wire them so you have 8ohms per sub, then bridge them down to 4ohms together. This way you can run a normal 2 channel power amp bridged down on it's channels without any trouble (most 2 channel amps can be "bridged" to give you a mono channel producing more power, this is done by combining the left and right signal with a combination of the + / - terminals). You might be able to do this with your current amp to get more sound for the time being.
 

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Ok so you have two 12" W3v2-D4 subs. Lets look at the wiring options (for those who can't view the pdf linked above); if wired in series they will provide a 4 ohm load to your amp, if wired in parallel they will provide a 1 ohm load to your amp.

The amp will run more efficiently on it's lowest impedance setting, i.e. an amp that does 300w @ 2ohm & 500w @ 1ohm. Think of a higher impedance load as driving into a head wind, vs driving with a trail wind, the drivetrain has to work harder & can't go as fast.

Dual voice coil speakers have four terminals on them, +/- for each coil.

Terminals:
AMP +/-
SUB1vc1 +/-
SUB1vc2 +/-
SUB2vc1 +/-
SUB2vc2 +/-

Linking the subs in single channel (mono)

Wiring two dual voice coil subs in series (4ohm):
AMP+ to SUB1vc1+ & SUB2vc1+
AMP- to SUB1vc2- & SUB2vc2-
SUB1vc1- to SUB1vc2+
SUB2vc1- to SUB2vc2+

Wiring two dual voice coil subs in parallel (1ohm):
AMP+ to SUB1vc1+ & SUB1vc2+ & SUB2vc1+ & SUB2vc2+
AMP- to SUB1vc1- & SUB1vc2- & SUB2vc1- & SUB2vc2-

There are other options for going two channel, but I won't put those up unless you want them (if they share enclosure space keep them mono, if they have individual chambers you could go 2 channel)

What make/model of 'flea market amp' do you have? I'll try to find the specs on it also, you may just need to change wiring schemes rather then amps.

~psguardian
 

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Discussion Starter · #11 ·
Actually my subs are not the v2, but the original w3's. And the amp just says "Metric audio, 1000 x 2" That is THE only thing listed on the amp.
 

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Discussion Starter · #12 ·
jaydubya2003 said:
Ok with dual 4ohm voice coils you can either get 2ohms on a sub our 8ohms on a sub, then you have to "bridge" that down for a mono amp to either 1 ohm by bridging the 2...2ohm subs together or 4ohms when bridging the 2...8ohm subs together or run each on a separate channel on a 2 channel amp (not recommended). What I would do is wire them so you have 8ohms per sub, then bridge them down to 4ohms together. This way you can run a normal 2 channel power amp bridged down on it's channels without any trouble (most 2 channel amps can be "bridged" to give you a mono channel producing more power, this is done by combining the left and right signal with a combination of the + / - terminals). You might be able to do this with your current amp to get more sound for the time being.
Currently, this is what I am doing (bridging the 2 channel amp.) I was looking at a new amp and stumbled across the mess or a wiring job. The guy TIED the wires onto the speaker terminals, has 3 wires going to one terminal, and none on the other, and has SCOTCH tape all over the place. I got a great laugh out of it.
 

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Skipping coils & scotch tape?! Yipes!!! That explains going into protect mode, it was saving your equipment from letting out the magic smoke....
What's that amp you're looking at? (& the one you have)

~psguardian
 

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dryvr12 said:
Currently, this is what I am doing (bridging the 2 channel amp.) I was looking at a new amp and stumbled across the mess or a wiring job. The guy TIED the wires onto the speaker terminals, has 3 wires going to one terminal, and none on the other, and has SCOTCH tape all over the place. I got a great laugh out of it.
Well it sounds like you've got things under control ;-)
 

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Discussion Starter · #15 ·
Haha I think i understand the basics, but there are parts that stump me. I looked on crutchfield for a wiring diagram. The way they were wired before, has 1 ohm imp. The way i am looking to do it is 4 ohm. I am hoping that if i wire at 4 ohm, and the amp is 4 ohm, i will be okay with what i have. The 2 ohm amp i was looking at was a sony xplod xs-1 i think. Now knowing i will need a 4 ohm, i have not begun to look into those.
 

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If you can properly wire them & the amp for 1ohm you will get more kick out of the amp & less heat. (lower resistance = higher efficiency, higher efficiency = less heat) if your current amp only does 2ohm/4ohm then yea wire it up for 4ohm.

~psguardian
 

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Your protect problem is definitely that crap wiring job. Fix that and wire so your amp sees a 4ohm load and it should at least play. Then when you decide you need more power, look into amps that are 1ohm stable and rewire down to 1ohm with the new amp.

Let me know if you to decide to start looking for a new amp, i can recommend some options that will be much better than anything sony makes for the same price :D also probably a better deal than anything you can find on crutchfield
 

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Time out guys, the "lower" (meaning lower #) the impedance the MORE heat will be created because the amp has MORE resistance thus working harder. dryvr12, to get the best results and make it the easiest to work with. Either go down to one sub wired at 2ohms, or stick with the 2 subs wired at 4ohms (8ohms per-sub) so that you can bridge a 2 channel power amp of any type and get some sound out of it.

The reason your amp was going into "protect" mode was because of the 1ohm load. If an amplifier is given a load it's not rated for it will only work (if at all) for a very short time as it heats up and either burns itself out or if it has it goes into "protect" mode.

If you wire them for a "bridged" 4 ohms, they will work with your current amp and many others if you feel the need to upgrade.
 
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