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Discussion Starter · #1 ·
Okay, so I am now bordering on annoying with my questions. Sorry, guys... :pc-ouch:

I have replaced all four speakers with Polk DB521s and the improvement is amazing. I will be stuffing polyfill in later today after a quick trip to Wally World.

I have the sub box pulled and have finally cleaned the nasty, sticky thing up. (PO seems to have repeatedly spilled sugary beverages into the box with no sub in place, so the entire internal box "floor" and all of the lower section of the sub indentation were covered with a sticky sludge with years of dirt mixed in with it. Gross. Thanks, PO, for yet another wonderful surprise!

I removed the stock amp and harness and plugged it in with an old POS speaker to test the four leads.

Both sets work fine, I am happy to report.

However, my wife said that the stereo sounded even better than when we added in the Polks yesterday. The nearly blown Alpine that was plugged into the sub harness was not putting out much sound on its own, so that was not it.

1. I have been running with the amp disconnected so that I could clean up the box and such. DOES THE STOCK AMP POWER THE FOUR SPEAKERS? If I plug the amp in does the system change in its power or does the amp really only power the sub itself? (The pin diagram I read shows wires to all the speakers. And it does have eleven pins active in the harness. Which leads to question two...)

2. If the amp does indeed enhance the speakers up front and above, why do they work with it not connected?

3. Since I will probably be getting the Kicker 6.5" sub and running from the stock HU and amp, it has to be a 2 ohm model. Yes?

4. WHICH ONE do I need? Again, stock HU, amp and wiring harness, 6.5" kicker sub, again, assuming 2 ohm...

5. I have read that I need to twist one of the pairs of wires to cancel the signal "from the chip". I am assuming that in need to put about ten twists into the pair that I will be using and not the other pair. Or do I even need to do this?

A quick response to question four would be great. I would like to go get this speaker today. I do NOT want to add an amp right now. All stock save for speakers is what I am aiming for.

Yes, I searched for a long time, but could not find questions answered directly, usually having answers that suggested other things or encouraged the asker to add an amp and get a better speaker. I am getting righteously confused here, guys... ;-) But I *will* keep searching. If you can help me as I am dredging the archives it would save me many hours. But I am searching. I promise!

Thanks!
 

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Okay, so I am now bordering on annoying with my questions. Sorry, guys... :pc-ouch:

I have replaced all four speakers with Polk DB521s and the improvement is amazing. I will be stuffing polyfill in later today after a quick trip to Wally World.

I have the sub box pulled and have finally cleaned the nasty, sticky thing up. (PO seems to have repeatedly spilled sugary beverages into the box with no sub in place, so the entire internal box "floor" and all of the lower section of the sub indentation were covered with a sticky sludge with years of dirt mixed in with it. Gross. Thanks, PO, for yet another wonderful surprise!

I removed the stock amp and harness and plugged it in with an old POS speaker to test the four leads.

Both sets work fine, I am happy to report.

However, my wife said that the stereo sounded even better than when we added in the Polks yesterday. The nearly blown Alpine that was plugged into the sub harness was not putting out much sound on its own, so that was not it.

1. I have been running with the amp disconnected so that I could clean up the box and such. DOES THE STOCK AMP POWER THE FOUR SPEAKERS? If I plug the amp in does the system change in its power or does the amp really only power the sub itself? (The pin diagram I read shows wires to all the speakers. And it does have eleven pins active in the harness. Which leads to question two...)

2. If the amp does indeed enhance the speakers up front and above, why do they work with it not connected?

3. Since I will probably be getting the Kicker 6.5" sub and running from the stock HU and amp, it has to be a 2 ohm model. Yes?

4. WHICH ONE do I need? Again, stock HU, amp and wiring harness, 6.5" kicker sub, again, assuming 2 ohm...

5. I have read that I need to twist one of the pairs of wires to cancel the signal "from the chip". I am assuming that in need to put about ten twists into the pair that I will be using and not the other pair. Or do I even need to do this?

A quick response to question four would be great. I would like to go get this speaker today. I do NOT want to add an amp right now. All stock save for speakers is what I am aiming for.

Yes, I searched for a long time, but could not find questions answered directly, usually having answers that suggested other things or encouraged the asker to add an amp and get a better speaker. I am getting righteously confused here, guys... ;-) But I *will* keep searching. If you can help me as I am dredging the archives it would save me many hours. But I am searching. I promise!

Thanks!
It would really help to know what year Wrangler and what stock sub you are talking about to be sure. But, since you are using 5.25 speakers, I am going to assume it's a TJ with the stock console 6.5 sub.

The reason I ask is because this happened before recently. The OP said it was a 6.5" sub and it was actually a 8" sub.

If your amp is disconnected then obviously it isn't powering the speakers. I believe what you are experiencing with the wiring is that the amp gets its signal for the sub from all four of the speakers.

When you say that the sound improvement is amazing and then you say that your wife said that it was better before, I'm a little confused.

Maybe you feel the sound is clearer and your wife is thinking that better means louder. And, the 2ohm speakers probably sound a bit louder than the Polk 4ohm speakers.

As for the Kicker, I believe the 2ohm model is the recommended one. Since the stock is a DVC sub the Kicker 2ohm DVC seems the best choice.

Kicker 40CWRT672 CompRT shallow-mount 6-3/4" subwoofer with dual 2-ohm voice coils at Crutchfield.com

The idea with the speakers is to stay away from cranking it up and pushing the loudness button. This will add horrible distortion to your speakers and you risk blowing them. You probably didn't hear that much distortion from the crappy stock speakers because they had less frequency range.

The proper way to power the speakers is to stay away from using the internal amp on the HU, via the loudness button, and get a clean external amp. This way you will have all the power of the high power HU, but you will have clean power. Also, make sure your speakers are in phase. This is critical to good sound.

The Rockford Fosgate Prime 50wattsX4 @4ohm, is a great match for the 45wattRMS Polk DB521's.

If you want even more fidelity, I.E. better sound, I would recommend a clean external EQ. The Clarion EQS746 is perfect for the TJ Wrangler because it fits into the space left by the single din aftermarket radio, and it is only $60. Plus, it is 0.005% Total Harmonic Distortion. You can really tweak the clarity and fidelity of your sound with this EQ. Most great home stereo systems will have an external EQ. Why should our vehicles be any different, if we want that same greatness?

Sorry, to say, but I'm sure you understand, that if you want better quality sound, you have to pay something for it. Note: There is a risk buying electronics online. If the box is damaged, I recommend sending it back.

Amazon.com : Rockford Fosgate R300X4 Prime 4-Channel Amplifier : Vehicle Multi Channel Amplifiers : Car Electronics

Amazon.com : Clarion EQS746 1/2 DIN Graphic Equalizer with Built-in Crossover : Vehicle Equalizers : Car Electronics

There are tons of write-ups for the sub replacement. Here are a few of them below. Hope this helps to answer your questions.

How To Replace The Factory Subwoofer - JeepForum.com

Center console subwoofer - JeepForum.com

http://www.wranglerforum.com/f40/replaced-my-blown-subwoofer-43529.html
 

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Discussion Starter · #3 ·
I meant that my wife commented that with the amp harness connected that the four Polks sounded even better than when we were running with amp removed from the TJ.

And yes, this is the same 2003 TJ with the missing sub that I have been on about in my other threads in this forum. Not my 2013 JK, which sounds just fine to me with the hard top on.

I was asking whether the speaker minus the sub worked better with the amp, as mine were disconnected and sounded pretty decent. (The four Polk DB521 speakers.) I had made a check of the four leads to the sub to see whether they actually worked. I plugged in one of the crappy 5.25" sound bar units that I had removed, just to see if the red/black and brown/gray pairs worked, which they did.

Later we went to purchase a Kicker. It was the wrong one. The dealer said that the Kicker 6.5" CompVT Car Subwoofer 2 OHM (10CVT652) had been discontinued and that this one was the replacement. It was the CompRT 67 6.75" compact sub. This speaker has the same four wire system with dual voice coils. It works GREAT, but it does not fit AT ALL. I had to cut a hole in the top of the box to get it to fit. It has eight screw holes and all are about 1/4" to 3/8" too far inboard. The very thin lip has a thick ridge at the edge which prevents the use of those metal nutsert things, so I have eight screws just barely holding this thing in place. I mangled everything to see if this was worth all the effort. Short story - it definitely is. I will build a box for the sub and figure out how to mount it. Wrong speaker, but still quite nice, and it is VERY loud with the stock system and amp. It is the 2 ohm, again with two coils and four wires like the stock system, but it does not fit at all like stock. Nothing like the one it replaced...

So this was a good experience, aurally, but not engineering-wise. I will fix the problems now that I know how much better this system can sound for so little money.
 

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I think I understand what you are saying about the wife now. She is saying that the Polks sound better when connected through the amp, whether or not the speaker is connected. This might be true because it probably completes some circuit.

Regarding the new subwoofer: I seem to remember that there was a writeup about how to install that slightly larger subwoofer into the stock location. If no one else chimes in with the information, I will look it up.
 

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I read this review of the Kicker 40CWRT672, which is 6.75" and has the eight holes. Everyone seems to say that it drops in with slight modification.

Kicker 40CWRT672 CompRT 6.75" Dual 2 Ohm Subwoofer at Crutchfield.ca

Here is one such comment.

I purchased this speaker as a replacement for the factory sub (which failed) in the factory center console of my 2004 Jeep Wrangler. The fit requires some trimming of the interior support ribs which took me about 5 minutes to accomplish with a Dremmel Tool, you will have to drill 4 new speaker mounting screws as well. The fit looks factory and the sound is far superior to what the factory speaker put out. I used the factory amp as well wired up on the 2 ohm side and am very pleased with the clarity, price and performance of the speaker. For a small sub it hits pretty good and sounds nice and clear with the factory radio/amp set up. I would and have recommended this to every Wrangler owner I know.
 

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Discussion Starter · #6 · (Edited)
At about 3:22 in the video you can see how these do NOT just "drop in" since the screws have to be placed so close to the edge. Maybe some kids think this is adequate, but for something that vibrates like a sub this will break pretty easily.

This one has the same size screw ring as my model. The screw holes have to be drilled so close to the edge that they will surely crack and come loose in the future. It is not a simply drop-in replacement as far as the mounting screws are concerned. Dremel-ing off the fins in the box is fine. That would fall under "minor modification" in my book, but destroying how the speaker is mounted to the box is not; it is very weak when mounted like this. Also, the diameter of the rear cover on the current version of the 2 ohm CompRT67 requires that you cut a chunk of the box's wall out to fit it. It is larger than it used to be, obviously. The current version no longer fits without a lot of modifying and compromising. Unless you can get the older version of the speaker I would not get this one. It sounds really great, but it also will probably bust loose from its box and become seriously damaged.

I need to either build a special box just for this sub or get another stock box and try a different speaker in it. If I build a box I guarantee that I will not use this small sub but will move up to a 10" one. If I get another stock, plastic box I will not use this speaker as it does not fit at all unless the box is mangled to that it is no longer a sealed cabinet.

Either way, I am pleased with what I got, as it is now working well. But I fully expect the box to break and the speaker to become damaged some time before this coming Fall.

This Kicker is a really nice speaker, and I will probably end up using it in my house for something.

https://www.youtube.com/watch?v=u7yd-MbNpyI
 
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