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      05-28-2010, 03:37 PM   #1
hkm
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Drives: 2010 Alpine White/Blac 325 E92
Join Date: Mar 2010
Location: Hong Kong

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DIY front door speaker mounting adapter

I'm in the process of upgrading the base system in my 2010 E92. I have already managed to mount the SWS-8 subs using the underseat enclosures and have run a four channel amp to run the subs and front door speakers. Details of that adventure here: http://www.e90post.com/forums/showthread.php?t=387129

I am now about to change the OEM 4" door speaker but my #1 goal was to maintain the OEM speaker grilles. For those of us with the E92 Coupe, this has been a big challenge. The E92 has even less clearance behind the door panel than the E90 so there's only a handful of speakers that are shallow enough to work--and many of them are not available in Hong Kong where i live. Fellow member Ksquare finally sourced me a set of Helix H234 components which are made in Germany and seem to have some reputation as decent entry-level performers. The cost for the set was about US$270. The mounting depth of the speakers is 48mm, so I knew it would likely be tight. The first 2 pictures show a comparison of the Helix 4" speakers and the OEM speakers.

Now that I had speakers, the next challenge was figuring out how to mount the Helix speakers. Due to the proprietary mounting points on the door panel, the Helix speaker could not simply bolt on. So instead I decided to try to create mounting adapter by sacrificing the original OEM speakers. As shown in the next 3 pictures, I ripped away the paper cone and then cut and grinded away the rest of the speaker and basket so that all that was left was the round speaker frame (I did clean it up with a dremel after taking this picture). What you will notice about the speaker frames is that they have a raised ring that extends about 5mm higher than the level of the mounting points. as a result, even though the speaker mounts are on the inside of the door panel, the speaker itself is about 5mm more forward and actually sticks through the hole in the door panel. My idea was to try and attach the new speakers ON TOP of this ring on the mounting adapter so that the speaker gain the benefit of this ring-height offset and sticks out through the hole just like the OEM speakers. Depth-wise, this method creates at least 5mm of additional rear clearance as compared to any mounting method that keeps the speakers on the back side of the door panel.

The top of the ring is 100mm in diameter, which is the same size as the outside diameter of the Helix speakers. As such, the speakers sat on the very top of the raised ring. To secure the speakers to the mounting adapter, I used a lot of silicone sealant (which also created a airproof seal between the speaker and mounting adapter). In pictures 7 & 8 the dark black parts are the original speaker frame, and the Helix speaker frame is sitting on top of it. You will notice that I had to remove the metal mounting tabs that came on the Helix speakers as those tabs would've prevented the OEM speaker grills from being reinstalled.

The last couple of pictures show the new speaker mounted in the panel. I did do a test and even though the speaker is protruding through the door panel, the OEM speaker grill can be reinstalled without interference.

As a final note, please keep in mind that my car is a post 3/09 build and the speakers used in both the doors and under the seats are different from earlier models. I have seen pictures of the pre 3/09 door speakers and while they are different, it appears that they could be used in a similar way as I have described here--but I haven't tried so I can't guarantee that it will work.

Onto the final project: modifying the tweeter sails so that the tweeters can point towards the windshield--as I've read a number of posts that say this will open up the soundstage.
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