AMGAffalterbach

[REAR DECKLID RATTLE/FLEX]

As long as I have been apart of the forums and I have owned my 2007 E550, I've had a major annoyance from the perspective of the sound system that I finally got around to solving and I should have done much sooner. To preface this, I had started a couple threads about this over the years and did a ton of searching and inquiry, but no one seemed to have a solution for what I have found to be a common issue on all W211s that have a deck-lid mounted subwoofer behind the rear headrests. I am not claiming I came up with anything new, as someone may have already done this, or other people have not experienced this issue, but if you've had any annoying rattling at certain bass frequencies, please read on.

In all E-Classes of this year I have ever been in, with the exception of the 2009, there is some level of distortion and rattling caused by the rear deck-lid of the car flexing at certain frequencies. I don't run my bass higher than 3 notches from 0 on the head unit, and I was finding this problem was more dependent on frequency than volume, as it would happen with certain songs instead of certain listening levels.

The cause of this is simply flex in the rear deck lid with or without the sunshade up, and with or without the removable piece present. I initially assumed by rear sub was bad or I needed to tear apart the rear portion of the car and dynamat everything, but the speaker was indeed fine, and when I tried tearing the car apart by removing the rear seat, the center headrest proved extraordinarily challenging to remove so before I broke anything I stopped there. I found if I applied a very small amount of pressure to the rear deck, that it would stop the rattling/distortion/vibration being generated by the subwoofer. To test, before and after, I used a song that had always been a perfect showcase of this rattle due to the frequencies it produced most priminently: Applaus, Applaus by Sportfreunde Stiller, the Gestört aber Geil Remix.

So, to solve this problem of rear deck lid flexing, I used a borescope to explore what section of deck lid I could drill through without damaging any speaker components or wiring, or majorly messing up any acoustic foam between the exposed metal in the trunk and the fabric/masonite material of the rear deck. I then procured two 1/4" carriage bolts approximately 4 inches long (I ended up cutting these to exact length using a Rockwell BladeRunner), filing/sanding the lettering off the top, and plastidipping the top of the carriage bolts to get a matte black finish.

To install these hold-downs that serve to keep the rear deck from rattling/flexing, I measured and marked two holes between the three rear headrests, far enough back to make sure I did not touch the speaker or ruin any components, while remaining far enough forward to miss the middle seat belt mount and tensioner. I used a 90-degree drill attachment and a 1/4 inch drill bit to drill all the way through the decklid and the metal framing underneath, and followed up with a drill bit two sizes larger to allow the square portion under the top of the carriage bolt to fit inside and thus allowing the bolt to sit flush with the decklid.

On the bottom side, I added a washer, locking washer, and butterfly nut so I could easily adjust the tension on the deck lid. I am still testing this to figure out if it will rattle loose eventually (note you can use a locking lug nut on this, but I like the ability to hand tighten without having to secure the top of the bolt), and if I have any issues I will use some Loctite or caulk to secure the butterfly nuts on.

As for the results... stellar. I have no distortion or vibration, no rattle or interference coming from the flex of the rear deck and my stock sound system sounds a million times better on ALL songs now, including the ones I avoided for a long time because I hated inducing that rattling noise. The space in the trunk is not hindered in any way, and the finish on the carriage bolts looks factory, but with much better sound quality. No rattling is present from any of the components I added, even with the carriage bolts having some play within the metal hole I drilled. It didn't take much tension either to solve the rattle, so only a few turns were necessary on the butterfly nuts.

PICTURES:


















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[AUXILIARY INPUT VOLUME AND QUALITY ISSUES]

The next issue I am addressing is the relatively low volume/lower fidelity of using the aux cable as an input the the Logic 7 sound system. Pinebaron had an excellent write-up on this where he used the speaker output lines on the AGW (stock amp) in the trunk, went to a line level converter, then to an external amp, then to the existing speakers to pump more wattage into the stock speakers. He found this lead to great improvement in sound quality and volume.

I also found, recently, that this can be affected at the source. I used my Asus ultrabook with a Bang & Olufsen ICEpower Class D amplifier in it as an audio source one day and discovered this lead to much less attenuated sound when using the aux cable as an input, as well as adequate volume on tracks that had previously been too quiet due to imperfect source.

So, therefore, the other solution to this problem is to procure a Fiio E6 mini headphone amplifier and go from source (iPod/Phone) -> Fiio E6 --> Aux In using regular auxiliary cables to boost the power the system is receiving from your device's built-in amp which is often inadequate, as can be shown by the difference in playing a CD and using your MP3 player as a source. While the Fiio E6 is NOT a DAC and doesn't contain its own sound card, the amplification works wonders, and to my ears the attenuated/thin sound of certain source files that were imperfect (Logic 7 seems to be very sensitive to poor quality sources), were immediately improved. Thanks to Nikko for being the guinea pig on this and finding the perfect sized amp for the job.

Thanks for reading my W211 audio rant, I have a new love and appreciation for this system, and the increasing problem of deck lid rattle I had has been solved. Lower mileage W211s didn't seem to have this problem as bad, but being a rear sear passenger in a few E55s has taught me this problem seems to exist on all W211s.

AMGAffalterbach

Just realized I could have hired an assistant to sit in the rear seat of my car and push down with minimal force on the rear deck. If anyone is looking for an unpaid internship please PM me.

garrettmoore

Tag.

garrettmoore

As a heads up to anyone else experiencing a rattle emanating from the subwoofer / decklid area, I tried this fix and it did not help. Upon further inspection, I found that the fabric on the driver side of my subwoofer had separated from the metal ring surrounding it.


To check if this is your issue, remove the center section of the decklid in the cabin, which pops right out. You will be able to easily see if your fabric has detached as well. If it has, simply use rubber cement or just about any type of glue to reattach it, let it dry, and you're good to go.

AMGAffalterbach

This fix is assuming all of your speakers are in working order and the drivers are not separated. Good info, but that should be the obvious first step in troubleshooting any rattles. For some reason I didn't experience any decklid rattle or flex in the 2009 models, as I think they're updated in either design or speakers.

ltcommander83

Excellent write-up on all counts. I have the same issue, never thought of it as a flexing issue. Even more impressive was the info on the line in audio source and the mini amp recommendation. It's super obvious as you stated when playing a cd with a 320k file and listening to same 320k file on a phone or mp3 player through line in. Will definitely be using these two great suggestions.

bflaig79

Great write-up. Very creative and hope it holds up for a long time. Even on my '03 E500 I have this exact same vibration issue. I do have the bass turned up more than 3 past the "0" and I have just managed by wedging a microfiber cloth between the rear window and the decklid
I do need to shift it around every 6 months or so, but I am definitely going to do what you did and hope it serves as a better looking/ more permanent fix

AMGAffalterbach

Thank you both for the kind words! As for the decklid rattle problem, it's been gone ever since, and I have not had to adjust the wing nuts at all, apparently it doesn't take a lot of pressure and I thought maybe I'd have to end up using Loctite, but no, it's held perfectly and I've forgotten they're even there.

As for the amp, ltcommander83, I don't really use it anymore. It definitely works well for boosting input volume, but I found the system too sensitive to clipping at high levels that wasn't bad but I couldn't stand hearing it. This does heavily depend on listening levels and what genre of music you listen to, but with some lower quality files I found this to be too much of a hassle to adjust the mini amp settings to get it to stop it from doing this. There are too many intervening variables here including amp type to tell you flat out not to do it, but just be warned.

Duc Tran

Hi bro, so impressive with your work. I got the same issues with HK L7 on my w212's rear deck lid. Do you have viber/whatsapp so I can ask you in more detail the way to clear this issue?

Many tks bro

lindainphx

Hi there, I have been trying to do some research on a rattle I have on my rear deck when I listen to music with high bass content in my 2016 E400 coupe. It has 25,000 miles on it and it’s still under the 100 day Carvana warranty. I took it into the dealership today in hopes that they can make repairs, But I’m not sure my Carvana warranty will include this type of repair.The warranty includes any issues that were normally covered under the manufacture warranty. Does anyone happen to know if a deck rattle is considered a warranty repair under a standard Mercedes-Benz coverage?