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Been hella sick the last week or so, but finally got bored of sitting in the house so came in on a sunday to knock out a log. 
Followers of our build logs over the years probably have seen us cram quite a bit of gear in some pretty limited spaces over the years...a lot of that has to do with our values of trying to make things look as OEM as possible and take away as little usable space as possible. This 2012 BMW 135i convertible, owned by our own member Tom aka. Tjswarbrick, is quite a good example of that.
We have known Tom a long time, and followed his progress in his previous mercedes C class, and interestingly enough, this project didnt quite start off as a space saving venture.
Like many of our members, Tom has collected a pretty extensive series of high end gear to be used in his next project...what he didnt know was the type of car that he was gonna purchase...as luck would have it, he ended up with a vehicle with VERY limited sacrificial space and very unique and limiting oem locations...and after sometime mocking up his existing gear, including arc SE amps, 12" subs, etc, and talking about just how much space he can sacrifice, it was decided that we would revamp most of the product list to better suit his desires for this vehicle.
the goals:
1. achieve a nice level of sound quality using oem locations
2. obtain a high level of bass performance despite the convertible configuration
3. sacrifice as little space as possible in an already limited trunk
Jesse did most of the work on this build, while Joey built the sub enclosure...i just did the tuning and the write up
lets get started.
first the car...this is our first 1 series of any kind, just happens to be a convertible
one of the biggest obstacles to making a convertible with a sealed off trunk sound good is the subbass performance. Subs located in the trunk separated by solid panels and the convertible mechanism, simply dont have a very good chance of getting into the cabin...thus, apart from unique vehicles such as the s2000, almost every other convertible we have done a subwoofer in the interior. The difficult part for this car is that it is a pretty small interior to begin with, so here is the view of that interior:
as you can see, it remains pretty much stock looking.
only very keen eyed owners of the 135 can perhaps notice that the passenger side floor mat is raised a little bit higher than normal...honestly, not being so familar with the vechile, i couldnt really see it even while i was taking the pics:
well, beneath the carpet lies a sealed enclosure housing an illusion audio Carbon C10 10" subwoofer.
the middle of the enclosure is finished in graphite vinyl, while the two sides were wrapped in the actual floor carpet that was trimmed and reattached. this means with the floor mat in place hiding the vinyl portion, it is very difficult to pick out the enclosure. The sub itself is protected by a press fit mesh grille that still allows a view of the unique C10 subwoofer:
here are some build pics of the sub enclosure by Joey. first, the area that will house the subwoofer enclosure was marked off and the carpet trimmed. one of the nice things about this car is that the passenger foot well is spaced up by a super thick piece of foam. with this section cut out of the car, it gave us quite a bit of room to build a decent sized enclosure and not protrude out too far from the oem floor level.
then the whole area was tapped off, and several layers of glass laid down to form the back side of the enclosure:
then joey got to work on the front baffle for the enclosure. with the unique front magnet design of the sub, the sub itself has to be inset quite a bit, so a stack of rings was built into the baffle to achieve that purpose. also, the press fit grille itself, which eventually becomes even with the front baffle, had to be several stacks high as well:
the side of the stack of rings was then ground down so it would fit within the confines of the floor mold, and then another top piece was attached, and the rings sealed off with druaglass:
this piece was then mated to the back mold, forming the complete enclosure of a little under .5 cubic foot, it is a bit small for the c10, but from past experiences such as our Mini and E30M3 build, we know the C10 performs beautifully in tiny boxes upfront.
the bonding area between the mold and the front baffle was then smoothed out, and basically, looking at this picture, the part that is in filler is how little the enclosure is raised from the oem floor...about 3-4 inches at the top and very little on the bottom:
the box was then fitted back into the car, and the edges backfilled to form a perfect fit with the car's foot well space:
when that cured and was sanded, the enclosure was once again test fitted in the car:
then came time to build the top trim layer, which started off as a single piece of 1/8" mdf. it was trimmed so the mdf itself will be in vinyl, while the sides in the salvaged factory carpet, and the difference in thickness between the two materials made for a flat top surface when done. :
so here is a pic to show just how far recessed the sub is:
and here is joey rabeting the inside edge of the grille to allow the mesh to be fitted from underneath the top most layer of the grille:
Followers of our build logs over the years probably have seen us cram quite a bit of gear in some pretty limited spaces over the years...a lot of that has to do with our values of trying to make things look as OEM as possible and take away as little usable space as possible. This 2012 BMW 135i convertible, owned by our own member Tom aka. Tjswarbrick, is quite a good example of that.
We have known Tom a long time, and followed his progress in his previous mercedes C class, and interestingly enough, this project didnt quite start off as a space saving venture.
Like many of our members, Tom has collected a pretty extensive series of high end gear to be used in his next project...what he didnt know was the type of car that he was gonna purchase...as luck would have it, he ended up with a vehicle with VERY limited sacrificial space and very unique and limiting oem locations...and after sometime mocking up his existing gear, including arc SE amps, 12" subs, etc, and talking about just how much space he can sacrifice, it was decided that we would revamp most of the product list to better suit his desires for this vehicle.
the goals:
1. achieve a nice level of sound quality using oem locations
2. obtain a high level of bass performance despite the convertible configuration
3. sacrifice as little space as possible in an already limited trunk
Jesse did most of the work on this build, while Joey built the sub enclosure...i just did the tuning and the write up
lets get started.
first the car...this is our first 1 series of any kind, just happens to be a convertible
one of the biggest obstacles to making a convertible with a sealed off trunk sound good is the subbass performance. Subs located in the trunk separated by solid panels and the convertible mechanism, simply dont have a very good chance of getting into the cabin...thus, apart from unique vehicles such as the s2000, almost every other convertible we have done a subwoofer in the interior. The difficult part for this car is that it is a pretty small interior to begin with, so here is the view of that interior:
as you can see, it remains pretty much stock looking.
well, beneath the carpet lies a sealed enclosure housing an illusion audio Carbon C10 10" subwoofer.
here are some build pics of the sub enclosure by Joey. first, the area that will house the subwoofer enclosure was marked off and the carpet trimmed. one of the nice things about this car is that the passenger foot well is spaced up by a super thick piece of foam. with this section cut out of the car, it gave us quite a bit of room to build a decent sized enclosure and not protrude out too far from the oem floor level.
then the whole area was tapped off, and several layers of glass laid down to form the back side of the enclosure:
then joey got to work on the front baffle for the enclosure. with the unique front magnet design of the sub, the sub itself has to be inset quite a bit, so a stack of rings was built into the baffle to achieve that purpose. also, the press fit grille itself, which eventually becomes even with the front baffle, had to be several stacks high as well:
the side of the stack of rings was then ground down so it would fit within the confines of the floor mold, and then another top piece was attached, and the rings sealed off with druaglass:
this piece was then mated to the back mold, forming the complete enclosure of a little under .5 cubic foot, it is a bit small for the c10, but from past experiences such as our Mini and E30M3 build, we know the C10 performs beautifully in tiny boxes upfront.
the bonding area between the mold and the front baffle was then smoothed out, and basically, looking at this picture, the part that is in filler is how little the enclosure is raised from the oem floor...about 3-4 inches at the top and very little on the bottom:
the box was then fitted back into the car, and the edges backfilled to form a perfect fit with the car's foot well space:
when that cured and was sanded, the enclosure was once again test fitted in the car:
then came time to build the top trim layer, which started off as a single piece of 1/8" mdf. it was trimmed so the mdf itself will be in vinyl, while the sides in the salvaged factory carpet, and the difference in thickness between the two materials made for a flat top surface when done. :
so here is a pic to show just how far recessed the sub is:
and here is joey rabeting the inside edge of the grille to allow the mesh to be fitted from underneath the top most layer of the grille: