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dbackfan12

Impedance Problem

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So today I smelled something burning in my car when I got home and when I opened my trunk there was smoke coming from the port of my box. I have a dual one-ohm 12 in DC XL in a 2.5 cubic foot slot ported box and I believe I had it wired at two ohms (positive to negative, negative out positive out). I pulled the sub out and it looks fine, the cone is intact and there's no visible damage but there is a strong burning smell coming from the magnet. Now the sub was still hitting hard when I first smelled the burning.

So here is the crazy part, when I check the resistance of the sub with my voltmeter it is at roughly 2.4 ohms so about 2 ohm. Is it possible that a sub could have somehow changed impedance on me? I did check the voltmeter on my other dual one-ohm sub and it checked outhe at about 1.2 ohms so the voltmeter is working properly. Any help would definitely be appreciated

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you are running a 12" xl in that big of a box.... sounds like its unloading on you.... when you go big box you lose power handling, how much power you running because you might be stressing the neck on it.... rusty told me to not do more then 1.75 on my level 3 if I wanted to push it to 1200rms..... XL is recommended at 1.5cuft so I would say 2.0 is really pushing it if you are putting 2000rms to it

how did a dual 1ohm sub read 1.2, did you only check 1 coil?

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Yeah, sorry for the confusion guys. I actually had it wired at 2 ohms, one wire going from positive to negative on the sub and a positive wire going into the amp and another negative wiring going into the amp. And yes I only checked one coil on my other dual one ohm sub to make sure my voltmeter wasn't going out on me.

And I actually blew the cone on this sub in the past but had it reconed by DC Audio. They also stated my box was a little too big as I am using a Fosgate T2000.1 at two ohms, and recommended an AR cone upgrade which I did purchase. I'm hoping the sub isn't done for as it was still producing some good output even with all the smoke but the fact that both of the coils are reading about 2 ohms when it should be one really worries me.

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You really should look at shrinking that box down. 1.75ft3 net would be the max I would want to see.

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You really should look at shrinking that box down. 1.75ft3 net would be the max I would want to see.

I was literally planning on making a new box to fit two of the XLS and have it at about 3.5 net cubic feet this week. They were both dual one-ohm subs so I was going to wire them up to one-ohm but now that this one is mysteriously reading 2 ohms Im not too sure what to do.

Update: So I double checked both coils on the sub that was burning and found that only one coil read's at 2 ohms and the other is still at one ohm if that changes anything. I also wired it up again the same way I had it wired previously and the load was reading roughly 3 ohms instead of two like it should have. Does this mean I cooked one of the voice coils?

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The XL coil is a 8 layer quad coil, the coils are parallel under the cap so the D1 woofer has a quad 2 coil in it. Thats why one side is reading 2 and not 1, that side has a smoked coil on it

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Some additional info. T2000 amps are more efficient at 2ohm. On average the birthsheets show 2400ish @2ohm and 2300ish @1ohm. Also infrsonic filter is 28hz, do you have it turned on? Are you trying to play below tuning? I not sure what the power rating is for the XL.

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XL subs are rated to 2200rms so you are running the right amp to it, so the only thing i could think of is you were running it way below tuning and unloading it with that big of a box.

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