How to install an aftermarket subwoofer and amp in your Jeep Wrangler TJ

Hey guys! I didn't have time to write because I was busy working on my Jeep
Today way the TJ-day. I bought a sub box with integrated amp yesterday and finaly found time today to put it in. It took cca. 6 hours of work. I tried to do it as tidy as possible. Lost my nerves near the end but it all came out fine.
I also finally found time to investigate the rattles and found that both front sway bar links have a lot of play, like half an inch vertically. It was probably hard to see when the Jeep was on a lift at mechanic's.
I am sorry for posting dropbox links as it wont be online for long, perhaps a month or two. Also sorry for shaking the phone, its hard to record and sway the jeep
https://www.dropbox.com/s/xtkqam7e2kiqmmq/20180422_131719.mp4?dl=0

Is this the right part to order? Do I need anything else?
http://rover.ebay.com/rover/1/711-5...0001&campid=5337789113&icep_item=232394669503

When I was done with that I decided to shake everything I can grab and search for sounds and found a rattle in the steering column, where the axle enters the power steering hub. There is no rotational play, only vertical and horizontal, so I was thinking of maybe tightening the screw on top, it is visible in the video. Would that help, or I should replace some bushing or something?

https://www.dropbox.com/s/atnu4anur7d99kg/20180422_133054.mp4?dl=0

Unfortunately the focus was off when I recorded the exact point where the sound was coming from.

Now for the sub install...
I wanted to make the cabling as invisible as possible and not make any permanent damage. First things first, I found an entry point for the +12 V supply from the battery. There is a large rubber cap in the middle of the cabin below the console:

I pulled the rubber plug out and carefully cut a hole for the cable to come through. Piece of advice: Put a drop of dish washing detergent on the hole, the cable will slide through a lot easier.


Then I put the cap back, without connecting the cable to the battery.
Next came hiding the cable below carpet and routing it to the back. Take your time on this as it is important to not pinch the cable or route it in a way passengers would be stepping on it. I got 3 shorter cables with the sub so I had to connect them. As I didn't have my soldering iron on me I went to a hardware store and bought this:


It was perfect for connecting 25mm2 cable to 15mm2 cable as the pieces I had didn't have the same thickness. In some point in future I will solder them together and put heat shrink tubing on the joint to make it waterproof.
It came out fine


Next was the ground wire. I had a hard time choosing the screw I would use and broke one torx tool trying to unscrew different ones.

In the end I went for one of the screws holding the rear seat and it proved to be fine.

Thats about the point when I started losing my nerves.
Then came the choice of signal supply. Since my sub amp has a speaker level input I chose to route cable from front right speaker to the amp (speaker was also dead, I removed it and I am also planning to upgrade it as well as other speakers in the jeep)

Heres a few pictures of that:


I so wish I knew I could fold the rear seat forward in 10 seconds, it would have saved me at least half an hour.
Interestingly, I used pins extracted from ATX power supply (standard PC power supply), squished them and put them inside original connector so I didn't have to cut it off. When I install a new speaker I will solder the pins directly to the speaker and connect the speaker this way.

The pins fit tight and I insulated them with some electrical and fabric tape. It seems fine this way.
Here is everything connected. I used a lot of zip ties in the process and a lot of creativity

I forgot to connect the + and remote turn on as can be seen on the pictures but I fixed it later. Amp has the auto shutoff and activates when it senses signal on the speaker input. Great engineering JBL!

And only pic of the sub I have is from my instagram story, I hope you dont mind
https://www.dropbox.com/s/37o1r824g6ngfxl/Screenshot_20180423-010513_Instagram.jpg?dl=0

It fits perfectly with no space to waste, has around 1'' clearance to the trunk door. Only had to remove the steel protective bars sub came with. Now it vastly overpowers the sound bar speakers so they will have to be upgraded soon. If you think 150W RMS is not enough, rethink. It is almost impossible to drive when its on 50% power (perceptive 50%). You just cant hear the engine. On the max power it shakes my ass And thats coming from a guy that once popped his windshield with 2x12'' setup.
BTW I also used ATX power supply connectors to connect the speaker line to the amp (also a great fit and used zip ties to separate them).

Have a nice day, I hope I helped somebody!
Heres the link for the sub:
https://www.amazon.com/dp/B007GYU30K/?tag=wranglerorg-20

Thanks man, I did my best to describe it in the most detail I could. Stock speakers are terrible...I hope to change the dash and sound bar speakers with 2-ways later this week, it should make a drastic change. I am also waiting for 1-DIN adapter to arrive so I could fit a multimedia system with bluetooth, GPS, etc. I will keep you guys posted!

That seems well matched!
I managed to find some Hertz speakers used for about 50$ (DCX130) for the sound bar. They are 40W RMS - knowing Hertz, they should be good for at least 50W RMS. Unfortunately I missed another pair of 4'' speakers for dash speakers from the same DCX series. I hope to find another pair soon. The plan is to replace the speakers and later get a small, high quality 4x50W RMS amp and put it somewhere in the dash. I am really surprised with how much space wrangler has everywhere under the plastic, so fitting it shouldn't be a problem. I think I will stick with the stock head unit for now because I love the retro look of it.

Thats exactly the kind of amp that I had in mind (not the marine option however). I think I'll have it summer ready in a month or so, so stay tuned
@Chris if I learned anything from my car audio modding mistakes its don't change it if its good enough. If you like your sound, stick with it. However, your speakers could handle more, in your place I wouldn't be able to resist putting some more kick in with a dedicated amp

I sincerely doubt that they would take 100W RMS for a long time. They don't look that way, more like 50W RMS and that much in a mid/high driver (speaker) should be more than enough for anybody.
And a bit of education - RMS means root mean square which is three fancy words telling 'average power'. With continuously changing signals like music it is probably the most descriptive and true rating of real power of an amp or driver.
You can also find other ratings as 'music power' or 'peak power', but they are very unreliable because they actually tell you nothing. There is no standardized methodology for measuring 'peak power' and manufacturers write whatever they want.
For an amplifier they could take an average max power the amp could put out for a milisecond or so and it would really peak there, but it actually means nothing. RMS is usually determined by feeding the amp or driver a perfect sinusoidal signal until the distortion reaches 1-5% THD, I don't know the exact numbers. THD stands for 'Total harmonic distortion' which means how much the output signal has deviated from the input signal. The important number is RMS power with 0.1% THD because that's where you want to be.
Analogy could be made with car power where they tell you the horsepower and torque numbers but do not take into consideration the torque curve which is the graph that tells you how the engine will perform in real life conditions. They also don't tell you the transmission gear ratios or fuel consumption at certain RPM and load, or speed, a figure which I would really love to see in a catalogue.
Since I don't feel like sleeping and haven't got decent sleep in days I'll keep writing, perhaps someone will find it interesting.
Would you like to know what destroys your speakers?
You could really put too much power in them but that is rarely the case.
Two main causes of speaker destruction are:
- Coil overheating from amplifier clipping. Amplifier is simply a voltage multiplier and it takes input signal and multiplies its intensity by a number. Multiplication factor is determined by design and potentiometer (gain/level knob). However, when the number is too high, output voltage exceeds amplifier's supply voltage and the signal flats out (if it was fed a sinusoidal signal it cuts the top or bottom of sinusoid off). That results basically in short circuit in your speaker and those are really bad because all of the applied power is converted into heat and no sound is being produced at that time. Try connecting a 9V battery to the speaker, you will hear a brief pop until the magnetic field has stabilized and then its stops moving. Current is still going through the coil and all of it is being converted to heat. Sound is being made by a constantly changing magnetic field, the same principle as an AC electric motor. Speaker is a motor of sorts. It converts electrical energy to movement. So getting your amp maxed out means that you are certainly getting into the clipping area, increasing the distortion dramatically and overheating the speaker coil. Just do the math - most car audio amps have DC-DC converters that turn your car's +14.4V to + and -30 to 60V, depending on design and power. If you for example have + and -30V supply in your amp, with the speaker coil resistance being 4 ohm, the current passing through your coil will be about 7.5A. If none of that power is being converted to movement, in that moment of clipping you have 30V*7.5A = 225W of thermal power being emitted from your coil. Thats huge! You could approximate that with 10% of the signal clipped you could average to 25W of heat being constantly dissipated. That may not seem like a lot, but thats same as heater in some soldering irons. Did you ever see a speaker coil? It is wound with really thin wire. With small car speakers coil ventilation is not really a priority like with high power subwoofers. Trained ear will easily recognize the clipping happening and turn the volume down.
Signal clipping
Also, a 50W RMS amp can destroy a 100W RMS speaker if it is operated in a signal-clipping manner for reasons stated above. And the higher frequency drivers are more vulnerable for two reasons - they are more efficient operating in normal conditions which leaves more room for power being converted to heat. Besides that, they have a lower mass which means that they heat up way more quickly. Old school way of protecting tweeters was putting a light bulb in series as it has a negative temperature coefficient. When the bulb heats up from excessive power its electrical resistance rises and less power is being delivered to the tweeter. But its not fast enough to fully protect the speaker from clipping effect. There are also clipping detect circuits that automatically decrease the voltage multiplier in input stage and make the clipping less likely to occur, but hardly eliminate it completely and distort the sound a lot. Those circuits are called compressor or limiter and they are quite effective, but the ignorance of the user is often too much even for those circuits.
- Mechanical damage from membrane overextension - when the cone moves beyond the designed travel length and either tears the rubber seal around the membrane or the coil goes off the guide and its bottom smashes and starts scraping around and making noise or damaging the coil

@Chris I know they wrote that, but in audio world 100W RMS into such a small speaker is a lot and I sincerely doubt that they would take that power for a long time. Especially with such a low price tag. For example, my 18'' Yamaha PA subwoofer is rated 400W RMS/800W music power. And the thing is huuuge. Unfortunately it died from clipping and was rewound twice so far. My friends also managed to kill 2 of my JBL Control 5 studio speakers tweeters which were rated 175W RMS with a 50W RMS per channel hifi amp in a matter of hours. And those speakers are like 400$ a pair studio reference speakers with built in bulb protection.

P.S. As I said, they look like 50W RMS speakers
https://www.dropbox.com/s/xe4so8q6ee2zx8q/Screenshot 2018-04-26 02.11.40.png?dl=0

False advertising is normal in audio world, except with premium brands like Hertz or Alpine top of the line series whose subwoofers can often take 1.5x rated power