Just finished adding some Hertz DCX100.3 coaxial speakers in the factory rear speaker locations and thought I'd share the way I installed them. This isn't a how to as far as getting to the rear speakers, as there is plenty of info on how to actually access them, however I struggled to find much information online about how others had fixed aftermarket speakers in, given they all tend to use 4 fixing points instead of BMW's 3 fixing points. There's info on this for door card installations, but not specifically for the rears.
I tried a few different things, like MDF adaptor plates, but felt they were too bulky to fit once the trim had been added back to the car. and so below is what I did. Very easy once you have the access (which itself wasn't as bad as most online advise, not in my experience anyway), but as you can see, the top two screw holes of the Hertz speaker line up with these factory fixings so no worries there, and that just leaves the bottom half of the speaker to secure.
I padded out the speaker location with 4mm foam insulation (just what I had lying around) as it seemed that without it the fitment would be prone to vibrations ruining the sound quality; as well as this the speaker mounting points would bend as you tighten the screws, which I didn't like, so the foam took out some slack.
I then took a nail plate (also lying around in my garage) and cut it into two pieces. With one half per speaker, I put one of the original speaker screws through a central hole in the plate and lined it up with the speaker in situ so I could scribe the outline of the speaker onto the plate and figure out what needed to be cut away - which I did with an angle grinder. That leaves you with the below installation so far.
When all screws are fastened, the nail plate will clamp down on the two lower fixing points of the speaker, and with the foam backing, both on the speaker aperture and the nail plate, they're pressed very tightly without metal on metal contact. Completely reversible and no damage to the car - very pleased.
A note to make here is that, in my case, since the foam insulation had a foil backing, and due to the way I'd packed out the speaker hole with foam, it was contacting the speaker terminals while powered, and caused a grounding issue, which is obviously less than ideal. So I cut off some foam from around the immediate speaker aperture and covered the rest with regular duct tape - looks nicer in black anyway. This eliminates any potential for accidental grounding of the terminals, so bear this in mind if applicable.
And that's it really, repeat for the other side and you'll have two very sturdy aftermarket speakers fitted into the rear speaker location. I then fitted the old factory speakers into the doors, since I have the basic 6-speaker option from factory, so why not. As you can see, with the rear trim panel back in place, it has plenty of clearance.
(Note: No speaker grill just to show clearance but they fit fine as well, no interference from the tweeter)
Onto changing out the footwell speakers now!
I tried a few different things, like MDF adaptor plates, but felt they were too bulky to fit once the trim had been added back to the car. and so below is what I did. Very easy once you have the access (which itself wasn't as bad as most online advise, not in my experience anyway), but as you can see, the top two screw holes of the Hertz speaker line up with these factory fixings so no worries there, and that just leaves the bottom half of the speaker to secure.
I padded out the speaker location with 4mm foam insulation (just what I had lying around) as it seemed that without it the fitment would be prone to vibrations ruining the sound quality; as well as this the speaker mounting points would bend as you tighten the screws, which I didn't like, so the foam took out some slack.
I then took a nail plate (also lying around in my garage) and cut it into two pieces. With one half per speaker, I put one of the original speaker screws through a central hole in the plate and lined it up with the speaker in situ so I could scribe the outline of the speaker onto the plate and figure out what needed to be cut away - which I did with an angle grinder. That leaves you with the below installation so far.
When all screws are fastened, the nail plate will clamp down on the two lower fixing points of the speaker, and with the foam backing, both on the speaker aperture and the nail plate, they're pressed very tightly without metal on metal contact. Completely reversible and no damage to the car - very pleased.
A note to make here is that, in my case, since the foam insulation had a foil backing, and due to the way I'd packed out the speaker hole with foam, it was contacting the speaker terminals while powered, and caused a grounding issue, which is obviously less than ideal. So I cut off some foam from around the immediate speaker aperture and covered the rest with regular duct tape - looks nicer in black anyway. This eliminates any potential for accidental grounding of the terminals, so bear this in mind if applicable.
And that's it really, repeat for the other side and you'll have two very sturdy aftermarket speakers fitted into the rear speaker location. I then fitted the old factory speakers into the doors, since I have the basic 6-speaker option from factory, so why not. As you can see, with the rear trim panel back in place, it has plenty of clearance.
(Note: No speaker grill just to show clearance but they fit fine as well, no interference from the tweeter)
Onto changing out the footwell speakers now!
Torquay
