Infiniti i35 has one of the worst Bose sound systems. In order to fix the problem, most people replace BOSE head unit with aftermarket stereo. I will explain how you can improve the quality without spending much money. This modification will help you with sound regardless whether you will keep the stock head unit or install a new stereo. Read full article.
As many of you know, Infiniti i35 has an open air sub. That means that in order for that sub to sound good, the trunk must be very well isolated. That’s when sound dampeners come into place. There are many sound dampeners out there with different price tags and I guess with different qualities. I used one of the cheapest brands, fatmat. I read good and bad reviews about them, but it worked for me. I got 12 feet of the dampening material for about $35.
Infiniti i35 also rattles in the rear deck when good amount of bass is produced. I fixed that by covering seat belt box (white plastic box) with the same sound dampening all around it.
I am gonna give you instructions on how to remove the rear deck as easy as possible without removing unnecessary items from your car.
1. Start by removing bottom back seat. To do this, you have to pull two white plastic handles located under the seat. Once you pull two of them, you can easily remove the bottom part of back seat.
2. Fold down the back seats. Don’t remove them, you can work on the car without taking them out.
3. Remove two corners of the seats. All you need to do is remove one bolt under each of those corner seats and then pull the corner seat up.
4. Now you have access to the black cover. It made up of three pieces; center, left, and right. Start from the center piece. Each of the pieces has two clips. In order to remove them, I used a flat screwdriver, but screwdriver should be as flat as possible to reduce amount of scratch you put on the cover. Some of the clips might break, but you can replace them any nearest Advanced Autoparts or Autozone. Even in dealership they should not cost too much.
5. After you remove all the clips and covers, you will be able to see the rear deck screws. By the way, you can remove now all covers and other parts from your deck, which include: center brake light, subwoofer cover, three child seat belt covers, and I think this is it.
6. In order to remove the four screws holding the rear deck, you need to use Philips screwdriver with a flat screwdriver. First use Philips screwdriver to unscrew the bolt, then use your flat screwdriver to work around the bolt to take it out. From my experience, I was able to successfully remove only one of the screws, all other three I broke, but was able to put them back in the place later anyway.
7. Now is the hardest part. It was pain in the a** to remove the rear deck even though all screws were out. Before you pull the rear deck, pull it up all around the rear sunshade because there are bunch of clips. After that, pull the rear deck up and pull to yourself. It might take many tries. It took me nearly 20 minutes first time I done this. The rear deck is very durable so I doubt you will break anything while removing it. The only thing you might brake is soft holders on the deck, which in my opinion are not necessary for the sound quality.
8. Next thing you should do is take two screws out of each seatbelt boxes. Now, get hair drier ready. Cut and then heat up sound dampening material. If you use fat mat dampening material, cover the inside walls of seat belt box twice because the material is little thin. Now cover sides of the seat belt assembly with that material. Make sure that when you put the assembly back to the white plastic box, it goes in tight and not freely.
9. Now that your seatbelt boxes and assembly are done. Take out subwoofer and take out the subwoofer assembly. Cover it all around with sound dampening, of course leaving a hole for the sub. By the way, I recommend you to get a regular 10mm wrench for the procedure. Two of the six screws on assembly are hiding under rear sunshade so it’s impossible to get there with bigger wrench. If you have the most regular thin 10mm wrench, it will save you good amount of time. So after you cover it with sound dampening all around, put it back and put the sub back in the assembly.
10. Now you have to just put the sound dampening all over the rear deck. I put second lawyer on top to get a better sound quality.
11. Now it’s time to put the rear deck back. Now be careful, what happened with me was that one metal piece came out of the deck right when I was putting it back and it made the sound just horrible. Make sure that nothing, especially metal, stays freely under the deck. Make sure that everything is attached securely. I would fold the seats up and test the system before putting everything back.
Well that is it. After successful installation you will notice that the bass sound much cleaner and about two or three times deeper. I think that this is what BOSE and Infiniti wanted to make, but looks like Infiniti made some mistakes by putting bunch of holes on rear deck and not providing good protection for rattling in the white seat belt boxes.
If you have any questions, feel free to post here.
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