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How to fix your HK sub/rear deck rattle! *30 Photos*

100K views 67 replies 52 participants last post by  sloveniaboy 
#1 · (Edited)
I have read a couple of DIY's and explanations on how to fix the common problem of the Harman/Kardon subwoofer system rattling the rear deck/parcel shelf. They all offer a different method of solving the problem, so I just wanted to post some photos of the process I used to fix the rattle and to make it clear exactly what must be done to perform this fix.

Here is a photo of the Harman/Kardon subwoofer. It is located underneath the rear deck/parcel shelf in the trunk.



There are 4 black screws and 2 white clips which hold the subwoofer in place. Note that there are no screws holding the rear of the subwoofer.

Left screw:



Right screw:



Center screws and white clips:



Step 1: Remove the 4 black screws using an 8 MM wrench.





Step 2: Remove the rear tabs holding the rear of the subwoofer in place. This is easiest if you crawl into the trunk and lay down on your back facing the bottom of the subwoofer. Push out (towards the rear of the car) and pull down on the subwoofer. The photos below illustrate how the sub's rear tabs will come out of the holes in the upper mounting structure.



Step 3: At this point, the subwoofer will be held in place only by the white clips. You DO NOT remove these clips from the subwoofer itself. Instead, while still lying on your back in the trunk, pull down on the front part of the subwoofer. Use some muscle, and the clips will *pop* out of their retaining holes along with the subwoofer assembly.



Step 4: The only thing keeping you from taking the subwoofer out of the trunk at this point is the power connector to the rear of the subwoofer. Simply pull the connector off to disconnect it from the subwoofer.



Here is the HK subwoofer assembly removed from the vehicle:





Here is a photo of the white clips that were discussed earlier. Previous DIY's have instructed the user to either remove or even break these clips. As you can see, they remain in the HK sub assembly and are removed with the unit as a whole. You do NOT have to break these white clips in order to take the subwoofer out!






Here is a photo of where the HK subwoofer mounts in the trunk. The 2 large holes you see in the steel structure simply allow sound to travel into the cabin rather than reflect off the metal if it were a solid continuous structure. These holes are where we will be stuffing our sound insulation to stop the deck rattle. The second picture points out the bottom of the rear parcel shelf as seen through the trunk.





My car was purchased used, and I believe that the previous owner brought this car into the dealer to try and fix the rear deck rattle at an earlier point in time. They used a small 3/4" thick/2" wide/3' long piece of foam and filled the rest of the space with yellow expanding foam (as pointed with the red arrows in the photo below). This solution obviously did not work! Also note the center hole in the steel structure (which is circled in red). This is the hole in which you can thread a carrier bolt to push against the bottom of the rear parcel shelf as per the "bolt" DIY from this link (however we will not be using a bolt in my particular DIY):

http://forums.bimmerforums.com/forum/showthread.php?t=132399



Before we begin stuffing the inner rear deck area with insulation, we must first decide what materials to utilize. A previous DIY suggested using bubble wrap, which is a cheap, viable solution. However, I chose to go with a polyester batting material which is perfect for this application. The batting will eliminate the rear deck rattle, as well as aid in giving the subwoofers more of a "thud" sound by providing extra insulation and sound deadening.



After some trial and error, I decided to cut the material into 2 large and 4 small sections. However, it turns out that I only used 1 large section of material and 2 small sections of material.





Step 5: Take the large section of batting material and stuff it in the center of the rear parcel shelf area, bridging the gap between the two large holes.

 
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#2 ·
Step 6: Take the 2 small sections of batting material, and stuff to the left and the right side of the large middle piece you just installed.



The stuffing procedure completed:





Step 7: With the stuffing complete, we can now reinstall the Harman/Kardon subwoofer. First, install the rear tabs into their mounting holes as show in the photo below.



Step 8: Next, secure the front of the subwoofer by snapping the white clips into their retaining holes. You will hear a loud click that almost sounds like a *crack* as these clips snap into their holes. The subwoofer will now sit flush against the steel structure, and is held in only by the tabs and clips.





Step 9: Install the 4 black screws into their appropriate locations:



Step 10: Be sure to reconnect the power connector to the subwoofer.



Step 11: You're done! Enjoy a rattle-free rear deck/parcel shelf and improved bass response. I hope that this DIY and its accompanying photos help you in repairing your rear deck rattle. If you have any questions, feel free to PM me or post a reply in this thread. Thanks! :thanks:

 
#3 ·
Just a thought.....

Bass boils down to the movement of air and in your photo's you maybe fixing an annoying rattle but it appears that your also dampening the flow of air that makes the subs work.

If it was me I would try to push the poly fill to either side of the hole that opens into the passenger compartment. The hole is there so the movement of air by the HK 6x9 woofer gets into the cabin of the car. Blocking that airway might result in less bass in the cabin of the car even though you have rid the annoying rattle....

Just my .02 Cents
 
#6 ·
Long Duck... you make a very good point. Although it is hard to tell by the photos, the batting is loosely stuffed into that area, aka, it is not *packed* in there, so there is still adequate movement of air and I have experienced no decrease in bass response. These are very weak subwoofers anyways, and at high volume are already distorting, so what little air they were able to move before is still being moved now (as evidenced by bass distortion at the same high volumes). In other words, I understand what you're saying, but everything still works. :thumbsup:
 
#29 ·
Has anyone tried dynamat? I had a similar problem in one of my E36's....but I also had a pair of 12's in the trunk.....I used dyanmat to cure it...

Just curious if it would work in this application....
That was my solution...



... use Dynamat to cover the whole underside of the rear shelf cover panel (1), specially the rear plastic vents (2) close to the rear window. I used thin strips of Dynamat under each individual vent section to make the whole cover panel assembly heavier, thus less vibration, no rattling at all.

Even there is some Dynamat in the rear speaker's grilles (9) (in the Harman Kardon aluminum-look strip) that I found that they rattled a little bit after installing the Stealthboxes.

No more rattles at all from the rear shelf. The same at the front door panels, Dynamat completely the suckers too:

 
#8 ·
very nice write up. my concern was the same as above, the sound. I'm sure that adding the insulation will damp the sound somehow, especially filling the ports that the sound goes through. I was looking into this recently because i added 2 tens the system and has an overly loud rattle. that being said, i'm gonna have to do the same, but with the extra subs really dont care for the performance of the stock subs.
 
#10 ·
If you added a pair of tens I would disconnect the factory subs....it might cure the rattle...assuming they are still hooked up.

Another thought would be to remove the factory sub enclosure. Removing it might allow enough air flow into the cabin to stop the rattle. Keep in mind that the rattle is caused by either too much air flow with no where to go, or the factory sub enclsure being pushed into the rear deck from the air movement of your added 10's.

I would start by removing the HK Sub enclosure first....it's an easy cheap shot to try before spening money to fix the rattle.
 
#14 ·
No man it's all good... love learning about audio!

My two previous vehicles had custom audio systems, but I haven't gotten around to doing anything with the Bimmer yet. I'd like to find a bass improvement solution that utilizes the stock HK sub enclosure, because my car is my daily driver and I really need the trunk space and do not want to add a ton of weight with an elaborate fiberglass or MDF sub setup. Any suggestions?
 
#16 ·
Wonderful write up and an informative thread. Not sure why my HK sub doesn't rattle. my car is a 2003 coupe. I have tried to crank it to induce a rattle but it sounds pretty good even at high volume and bass. Is the HK the greatest sound system? no. But is is pretty good and cosmetically melds with the interior. :)
Thanks again,
George
 
#21 ·
Do all H/K subs look like that? I have an '01 330i with the H/K sound system and it looks nothing like that under my back deck. I do have an aftermerket head unit though so maybe the PO replaced the subs too. I don't have any rattle either which I guess supports the theory that what I have isn't stock...
 
#24 ·
is there any fix like this for a non HK system? or maybe something similar to the bolt fix for a non HK? Thanks in advance
 
#25 ·
The rattle id due to the rear deck bouncing and not being properly secure by the retaining clip provided by BMW. The best fix is to buy the soft velvent tape, it is sticky on one side and the other is a thin velvet like material. After you line the outter edge of the rear deck then you can use a single nut and screw to secure the rear deck down to the front, it provides more support. When i did my rear system I removed the Rear HK subs all together, one becaue it was in the way, two because my new subs would make it obsolete anyways, and three, well there is no three. Any how I will take updated pictures of the bolt im taking about.

BTW my HK OEM subs with out the OEM amp is forsale.
 
#27 ·
yea pictures of what you speak of would be great AzCamel. Thanks.
 
#30 ·
Technic,

What components u running, on the door panels. And rear for that matter.
 
#32 ·
Is the HK sub tapped off from the rear deck speakers? My sub is not working any longer... I test the sub itself and it works, but it is not receiving audio from the head unit. I think that when I put the batting in there, I may have disconnected some wires connecting the subs to the rear deck speakers. This is the only conclusion I have come to since my sub stopped working... any of you have experienced this problem? :dunno:
 
#34 ·
Thank you soooo much. I performed this fix a couple days ago and everything went exactly like you said. It was easy and the rattle is completely gone. I think the bass sounds a little crisper even.

For you to go out of your way like that for the benefit of others and get nothing in return renews my faith in humans. (Not to get to cheezy or anything)

:thumbsup:

Now if I could just get my AM radio reception to work.......
 
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