Guide 2nd Generation CX-9: Bose subwoofer improvement
- Thread starter sm1ke
- Start date
- :
- Canada
Sorry, I don't think my mirror ever vibrated so I don't know if the improvement would help. If your mirror is vibrating, maybe swing by the dealer and see if they can help? Sometimes all it takes is a few well-placed pieces of foam tape.
That’s some good advice! Thank you!
cbogey88
Member
This is a DIY guide that details how to reduce the "muddy" bass from the Bose subwoofer mounted in the spare tire. This fix has been done by many others on this forum (originally jgriffter, followed by PTguy, jmeitz, Zoom49, greggmischenko, and others). I recently did the same mod, and I just thought I'd document and organize it to show how easy it is to do.
This process was photographed by myself, using my cellphone camera, my old DSLR and my 2018 Mazda CX-9 Signature as the "demo" vehicle. While the instructions are written by me, many references will be made to the various posts from the users named above. This DIY is provided as a learning aid and reference guide. I assume no responsibility for any warranties this process may void, or damages you may inflict on yourself or your vehicle.
What you'll need:
- 21mm socket or wrench (or the tire iron from the emergency jack kit)
- 1/4" socket
- Sound deadener
- Poly fill (pillow stuffing)
- Box cutter, scissors or Xacto knife
From jgriffter's original thread:
For the sound deadener and poly fill, PTguy recommends Parts Express.
I personally used three sheets of 10mm thick, 20x12" deadener from eBay, but if I had to do it again I would spend a bit more and buy the deadener from Parts Express. The adhesive on the eBay deadener isn't very strong, and the thickness makes it a bit harder to work with. For poly fill, I pulled some out of an extra guest pillow I had lying around. Since the guest pillow wasn't used much, the poly fill in it was not compressed, which was perfect.
1. Remove the subwoofer from the car by unplugging the harness (1) and loosening and removing the 21mm bolt (2) that mounts the sub and spare wheel to the car.
2. Remove the 7 1/4" screws (3) on the top cover (4) and set them aside.
3. Remove the 4 1/4" screws (5) securing the speaker (6) to the housing (7).
4. Fill the housing with poly fill (8). It doesn't need to be packed in, just lightly fill it. Screw the speaker back into the housing.
5. Apply sound deadener (9) to the outside of the housing. I forgot to take a photo, but I also applied deadener to the flat surfaces around the speaker.
6. Apply sound deadener to the top of the cover (1O), then screw the cover back onto the housing.
7. Reinstall the subwoofer. Don't forget to plug the harness back in.
Here's the finished product.
Here's jgriffter's thoughts after adding poly fill and sound deadener:
This is basically the same experience I have after doing this mod myself. The bass is noticeably tighter and cleaner after this mod. I listen to almost everything, but it's mostly rap/hip hop, rock and some electronica. I noticed that because the bass hits cleaner and tighter, it doesn't drown out the mids, and the music sounds more uniform and "right".
I did this yesterday just with the polyfill. Sounds far better already. The sub really thumps a whole lot tighter and the overactive "boooooom" is essentially gone.
I may get some sound deadener still to add to the top of the sub, but that seemed like a pain in the butt to do, so I figured I'd just try the polyfill first.
Thanks for the idea.
This is a common mod in the VW hatchback world, and when their
sub is faced DOWN, with the tire on top it gains even more!
Now, its my wife’s ride so I gotta wait to try it, but hopefully that contribution will work for the Mazda community as well.
VW’s reasoning for not firing the sub down was because if there was water intrusion, it would only puddle water around a spare tire.
However, since I clean my drain points I will try firing it down, but also have easier checking of the OFTEN neglected spare tire pressure, so you don’t have a flat to replace an unfortunate flat if you do need the spare.
I wonder if anyone has done foam speaker backings for the door speakers and poly fill there?
sub is faced DOWN, with the tire on top it gains even more!
Now, its my wife’s ride so I gotta wait to try it, but hopefully that contribution will work for the Mazda community as well.
VW’s reasoning for not firing the sub down was because if there was water intrusion, it would only puddle water around a spare tire.
However, since I clean my drain points I will try firing it down, but also have easier checking of the OFTEN neglected spare tire pressure, so you don’t have a flat to replace an unfortunate flat if you do need the spare.
I wonder if anyone has done foam speaker backings for the door speakers and poly fill there?
