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Confirming the TJ's subwoofer impedance is 1 ohm....

Discussion in 'TJ General Discussion' started by Jerry Bransford, Apr 8, 2017.

  1. Jerry Bransford

    Jerry Bransford TJ Guru
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    I have read that the TJ's factory subwoofer is only 1 ohm and that the factory amp is 75 watts into that 1 ohm impedance.

    Can someone confirm it's truly a 1 ohm speaker? The replacement 6.5" subwoofers I have found are all either 2 or 4 ohms at the lowest.

    I understand impedances and their effect on power etc., I only want to confirm that 1 ohm spec for the factory subwoofer.

    NO, I'm not upgrading the subwoofer to something bigger... at my age I just don't want or need a bigger subwoofer, please don't waste your time trying to convince me. :)

    Edit: Just found more info that makes sense... it appears the stock subwoofer has dual 2 ohm voice coils wired in parallel which is how it gets its 1 ohm impedance. This sounds reasonable as 6.5" subwoofers with dual 2 ohm voice coils are fairly easy to find.

    The least expensive 6.5" dual 2 ohm voice coil subwoofer speaker I have found is $90 but considering my limited needs is more than I want to spend for just a low-use subwoofer. http://rover.ebay.com/rover/1/711-5...0001&campid=5337789113&icep_item=222455261918

    Has anyone replaced their TJ's subwoofer with a direct replacement they can recommend with a link?
     
    #1 Jerry Bransford, Apr 8, 2017
    Last edited: Apr 8, 2017
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  2. derekmac

    derekmac TJ Addict

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    I think I remember reading a good thread on this subject here, but for the life of me can't find it. Maybe @Chris will be able to find it.
     
  3. Chris

    Chris Administrator
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    Jerry is going to replace it with some big subs and really blast his bass heavy hip hop, I can picture it now.

    This is what I used Jerry:
    https://www.amazon.com/dp/B0036MOQAE/?tag=wranglerorg-20

    If you read the reviews, you'll see it's a popular option for a replacement sub for our TJs, lots of guys with TJs have left reviews.

    So while I can't comment on the ohms of the stock speaker (looks like you figured that out), I can confirm that this speaker does indeed work, and sounds good!
     
  4. Jerry Bransford

    Jerry Bransford TJ Guru
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    Thanks Chris. The only problem with that speaker is it has a 4 ohm impedance which would reduce the TJ's subwoofer amplifier's wattage level. The TJ's subwoofer is designed for a single 1 ohm speaker. See my answer to Bad Lieutenant's thread on this subject.

    I did find a good direct replacement subwoofer speaker but it's $90 which I won't spend for a subwoofer for the Jeep.
     
  5. JMT

    JMT TJ Addict
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    Here the speaker Chris mentioned in stock for cheapest I could find.

    https://www.newegg.com/Product/Prod...gclid=CNbO0rDFltMCFR25wAodVzoFbQ&gclsrc=aw.ds
     
  6. Chris

    Chris Administrator
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    Which goes to show how little I know about electronics... Haha.

    You could always buy the replacement from... Ugh... I'm about to say it... Quadratec!
     
  7. cliffish

    cliffish Member

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  8. Head Lice

    Head Lice TJ Enthusiast

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    Which is what I did. Did read the reviews both pro/con about this speaker. Mine seems fine.
    After operating logging equipment 40+ years, my old ears aren't that refined anymore.
     
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  9. JeepZilla380

    JeepZilla380 Member

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    I've used this one in Two of my TJs and have been pleased overall. It beats the OEM one, and does alright for the music I listen to (classic rock, alt rock). Can't beat the price. It does take a bit of dremel action to get it to fix, but nothing to terrible.
     
  10. ohiopatriot

    ohiopatriot Member

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  11. Shwane

    Shwane Overlander
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    +1 for this one.

    This one is actually the "RT" Its weather proof and is stable at 1ohm. It's a dual voice coil 2 ohm speaker designed for tight spaces. You;ll have to trim a little bit, but nothing drastic.

    Look it up on amazon, a few wrangler guys use it.
     
  12. VallenMaes

    VallenMaes TJ Enthusiast

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  13. Jerry Bransford

    Jerry Bransford TJ Guru
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    How is that sub connected? Was it a replacement for the OE factory center console sub? Have you also recently installed a new aftermarket head unit? There is a power lead (gray with an orange stripe) from the OE factory subwoofer assembly that has to be connected to a switched sub or antenna power lead from the head unit to provide power the OE factory sub amplifier. And make sure the black wire from the subwoofer assembly is grounded too. The OE factory subwoofer amp was only an option for 2003 and newer TJs.
     
    #13 Jerry Bransford, Nov 15, 2017 at 11:08 AM
    Last edited: Nov 17, 2017 at 10:20 AM
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  14. JMT

    JMT TJ Addict
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    x2^^^. We need to know more information. The more you give us the easier it is to diagnose how to set up!
     
  15. bobthetj03

    bobthetj03 TJ Addict
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    Not to stray, but where is the factory sub amp located? Is it in the center console next to the sub? And, can you still use it with an aftermarket head unit, or are they proprietary like BOSE does on some factory car audio systems?
     
  16. Jerry Bransford

    Jerry Bransford TJ Guru
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    The factory sub is in the center console and yes it can be used with an aftermarket head unit. I'm running mine with my Sony radio.
     
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  17. VallenMaes

    VallenMaes TJ Enthusiast

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    I have an aftermarket header. Its a Pioneer. i havent even been able to look at anything because i cant get it apart. I think the PO used some glue. I know the sub works as ive tested it on my buddies system in his car while he was putting it in. To be honest thats about all i know. Ive never dabbled in putting audio together in a car. I do know that the factory sub was so degenerated that the cone fell apart as i pulled it out. Not sure if any of this helps but thats what i know.
     
  18. fyr145

    fyr145 New Member

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    I just replaced my OEM sub speaker with the quadratec speaker, then reconnected it. Still no luck. I have a pioneer head unit as well but looked at the wiring diagram then tore apart the dash but couldn't find the "radio choke relay" it shows in the diagram. I did see the power from the fuse block is #3 and that's fine so I'm stuck.:(
     
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  19. Jerry Bransford

    Jerry Bransford TJ Guru
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    There is no "radio choke relay", there is however a power lead from the radio that turns on with the radio to power the OE factory subwoofer. That power lead is called various things like 'aux amp', 'antenna', 'switched power'. 'amplifier turn on', etc. but unless the OE subwoofer amp input power lead receives 12v from one of those wires, the amp won't turn on. It is off unless turned on by a power lead from the radio. Take a look at my post #13 above.
     
  20. RangerRick

    RangerRick TJ Enthusiast
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    @Jerry Bransford
    I stand corrected as I measured the speaker in my original article so here's the result:
    The factory sub was 2 Ohm per voice coil. BTL they come to 1 Ohms total. If you use a 1 Ohm per coil speaker, the resulting load on the amplifier will be 1/2 Ohm and I highly doubt it will be stable at that rating. I recommend using the 2 Ohm DVC speaker making 1 Ohm BTL total load seen by the design of the IC amplifier chip for stability even though total it is 1 Ohm for stability and heat reasons. The IC amplifier chip will get very hot running into two 1 Ohm coils since it will look like 1/2 Ohm load to the device and several audio folks don't recommend that low of an impedance to amplifier IC's unless they are designed specifically for this. Examples would be Class D subwoofer amplifiers in the aftermarket world can run into sub 1 Ohm loads and make gobs of stable power. Read my how to post showing how I replaced mine with a Kicker comp speaker available with dual 1 or 2 Ohm voice coils. You will have to trim the small ribs from the inside of the factory sub enclosure for the much larger magnet to fit and seat properly. I ended up totally bypassing the factory amplifier module because it is really in reality only a 30W audio device operating into that load absolute peak power with a hurricane blowing it down hill. I purchased a Kicker amplifier made for ATV's and off-road motorsports that drives the sub much better than the factory weak stocker amp. The amplifier Kicker makes is so small, it fits up under the dash near the radio and is totally up out of harms way, plus it was made for mud & dirt to get on it a little without frying it instantly like other non-marine grade equipment. I am very happy with the results and would do it again because nobody can tell it's not stock so the thieves don't get tempted and no cargo space loss from aftermarket sub enclosures etc.....

    Speaker part numbers: 43CWRT672 for the 2 Ohm, 43CWRT671 for the 1 Ohm per voice coil.
    Amplifier part numbers: 42PXA300.4 300 Watt 4 channel amplifier, They also make a 2 Channel but I wanted 2 extra channels for the waterproof wake board can speakers mounted on the rear roll bar.

    Link here to my post on replacement: LINK
     
    #20 RangerRick, Nov 17, 2017 at 9:16 AM
    Last edited: Nov 17, 2017 at 9:52 AM

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