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Problems with Subwoofers

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Old Jul 22, 2015 | 03:34 PM
  #1  
Sethers775's Avatar
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From: East Bay, CA
Year: 2000
Model: Cherokee (XJ)
Engine: 4.7L Stroker
Default Problems with Subwoofers

I bought 2 12" crv kickers in a box that came with a 1000w amp, they were tested for me before i bought them off a friend so I know they work, once I put them in my cherokee, wired them up, and tried playing off them, they would (and still do) only go up to the power of about 1 8" sun before cutting out and only hitting for a second. So in order to use these beasts, I have to play music rather quietly. To try to fix this, I rewired everything, Bought a new stereo deck, checked the wiring on it, bought thicker speaker wire, redid all connections, and reground it. I then tested my battery with a multimeter, and I was only getting 9v when the car was running, so I replaced the alternator yesterday. Replacing the alternator did nothing for the subs (but did speed up the windows) anyone have any more ideas?? Considering just buying the little 8" kicker from quadratec that fits in the right pocket of the trunk, cause the box on these 12s takes up half the trunk space!
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Old Jul 22, 2015 | 03:59 PM
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Sounds like something is going on with the amp.
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Old Jul 22, 2015 | 08:42 PM
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What size wire did you run for the power for the amp?
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Old Jul 23, 2015 | 02:16 PM
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From: Orange County, CA
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Originally Posted by xjmarc
What size wire did you run for the power for the amp?
Lol I have a feeling this is the source of the problem.... I had this issue on my Suzuki, it was the fact I was trying to power a 1500W mono with 8AWG....

Now I just run 0 gauge, that way if I ever have to upgrade I know the cable can probably handle it and I don't have to pull up trim and re-run wire.
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Old Jul 23, 2015 | 05:28 PM
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From: East Bay, CA
Year: 2000
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Default Problems with Subwoofers

I have fatty wires for the power to the amp, 0 i think, and 16 for amp to subs

Last edited by Sethers775; Jul 23, 2015 at 05:33 PM.
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Old Jul 23, 2015 | 05:46 PM
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Are you using cheap RCA leads from the HU to the amp? When the amp "cuts out" does it go into protection, or just die completely?
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Old Jul 23, 2015 | 11:24 PM
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From: lake stevens, wa
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unhook one sub and tell me what happens
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Old Jul 23, 2015 | 11:53 PM
  #8  
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Originally Posted by XJlimitedx99
Sounds like something is going on with the amp.
x2
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Old Jul 24, 2015 | 10:32 AM
  #9  
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Originally Posted by Turbo X_J
Are you using cheap RCA leads from the HU to the amp? When the amp "cuts out" does it go into protection, or just die completely?
This is a good thing to look into.

Since you said they worked before you bought them that could indicate its in your wiring.

Do you have the same size ground as your hot lead?

If the amp is going into protection mode then it's not your remote because the amp is staying on. I'd follow Turbo's advice and look into your RCA cables.
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Old Jul 24, 2015 | 02:08 PM
  #10  
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From: Warren County , NJ
Year: 1996
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Engine: Inline 6
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I did the same thing. I went from 2 12" subs in the trunk to the Quadratec Woofer in the cubby. Very pleased with it. Plus I got trunk space back. My amp is mounted on the back of the rear bench and the wiring for the speaker is tucked under the mat.
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Old Jul 28, 2015 | 07:19 PM
  #11  
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From: Missoula, MT
Year: 1999
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Engine: Golen 4.6 Stroker, AFE Headers, 62mm TB, 24 LB Injectors, Brown Dog kit, HF Cat, 3" Exhaust
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I had a bunch of different sound system in my younger days... My last one disappeared after floating around in the back.

Anyways, like they said, It has to be in your wiring somewhere if they worked elsewhere. Possibly not a good enough ground? Try sanding some of the paint off and using a quality screw/bolt to ground it. Maybe you have the settings on the amp all messed up? If you can't get enough consistent power from the Jeep, add a cap.

If everything is correct, your amp is probably shot.
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Old Jul 29, 2015 | 03:08 AM
  #12  
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Year: 2001
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Did you clean the metal surface you used as a ground from paint rust etc?
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Old Aug 12, 2015 | 08:44 PM
  #13  
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From: Middlefield, Ohio
Year: 2000
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I agree with what everyone says about the ground but also how high is volume set on the amp? If set to high, it will keep tripping. Start low my friend...
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Old Aug 13, 2015 | 10:21 AM
  #14  
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first, you do not need 0 gauge wire for an amp. even a 1000 watt amp-- unless you're telling us that's its rms rating, is never going to run at 1000 watts continously. it's only going to run at around 650 -- maybe. So don't buy into the "gold plated, platnium core, helium filled -2 gauge wire". It's the stereo market's attempt to get us to buy $200 wiring when $20 wires will do. The only thing sillier is getting gold-plated hdmi or dvi wires... but I'll stop the rant right there. use decent braded 2 gauge, and that will be MORE than enough for what you're doing (even if the amp was drawing 1000 watts continuously). and don't bother with the gold plated monster crap, it's a waste of your money.

Anyway, with the issues you described, and assuming the amp is working properly --

1) Ground, ground, ground!!! Ground the amp as close to the amp as possible. Use a good, 2 gauge braided wire. More importantly, gound it to a good SPOT... if you're in the cargo area, cut away a portion of the carpet, find a good, solid bold into the body. Sand all the paint off that spot, get down to bare metal. and ground. DO NOT run a wire to your radio. Do NOT ground to some random bolt. 2/3 of most newbie amp issues arise from poor grounding.
2) how are the speakers wired ? Assuming you're grounded properly, are you running them in series or in parallel? A series connection will give you higher impedence, and will draw less current. a parallel connection will present a lower impedence to the amp, but will drive it harder. (if you're interested, for a series connection [i.e., "-" terminal of one speaker to the "-" speaker terminal on amp, "+" and "-" terminals on the speakers connected, then "+" terminal on speaker connected to the "+" speaker terminal on the amp], impedence is calculated by just adding up the impedence of the speakers -- so if you're running two 4 ohm speakers, a series connection will present an 8 ohm load to the amp. If you ran the same speakers in parallel, you average -- so you're get 4+4/2, you'd be presenting a 4 ohm load to the amp. Since parallel loads present a lower impedence, it allows the speakers to pull more current (rembmer, current = v/r. We're keeping voltage constant, and decreasing the "r"), but will drive the amp harder-- I've seen many name brand amps that say they're "1000 watts" but they're really only publishing peak watts, and they fall apart when driving a low-impedence load... anyway..)

TRY connecting just a single speaker to see if this is an issue. If you connect a single speaker, and this clears up the problem, try running the speakers in series connection and see if that remedies the problem.

3) actually, as a first step, check the gain setting on the amp. Is it maxxed out? Lower it to the lowest setting. If that helps, then raise it until it starts cutting out again. Again, this is indicative of an amp being driven too hard.

4) also, as someone else said-- if this is a qulity amp, there should be a "protection" LED that lights up when it is being driven to hard and shuts off-- check to see if that led is lit up.

If you decide to get a new amp, always, always, always go by the rms rating, not peak. Manufacturers will spill "1000 watts" all over the packaging, and bury in the specs that it produces 1000 watts only in peak spikes, and produces only 500 watts rms. AND, keep in mind what load you're running. They also typicall will publish 8ohm loads. For a low range amp that's producing 500 watts into an 8ohm load, that same amp may only ba able to produce 300 watts into a 4 ohm load. AND, that will likely only be in mono mode-- if you need it for stereo for any reason, that same 300 watts is now 150. So, very ,very quickly that nice, brand new 1000 watt amp is really just 150 watt amp.

There's a TON of misinformation out there... and a lot of good forums just like this (carstereo.com is a really good forum-- I'd suggest you post over there for more detailed advice-- those guys will jump all over your issue. Heck, you can even just give them the model name of the amp and they'll tell you if it's worth the time to salvage it).

Last edited by jmg; Aug 13, 2015 at 10:28 AM.
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Old Aug 13, 2015 | 10:58 AM
  #15  
Sethers775's Avatar
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Thanks for the mass of info, I will be testing my amp this weekend, and confirming how well the ground is set.
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