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.
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.