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Had a nice summer with the SLS, but I cant stand the stock stereo system. If it was a coupe this would be a no brainer install with custom sub box in the trunk ported to the cabin. However the roadster offers some huge challenges. There is really no space even though this is a huge car to put any subwoofers. The only other custom route would be a passenger foot well custom sub enclosure with amp. But I want to leave the car as unmolested as possible.
You cant use the trunk in the roadster since the top when down seals it off. So that left basically behind the seats...which also has hardly any room. The only solution I could find was very small integrated 8"subs with amps from Alpine.
The plan is to tie into the mid fuse box with fuse taps(lots of spare fuse spots) And then use the amps high power signal capability to steal the signal from the side 3" speakers, it also acts as a remote turn on as well. So I dont have to go ripping apart the car to run RCA or power/remote from the stock headunit. This will allow a very clean unmolested look. The wires will run behind the carpet in a custom wire loom I will make and poke out at the floor to connect to the amps. To mount the sub/amps I will use velcro and they will be hidden behind the seats. (it is SUPER tight fit behind the seats, there is only 1/4" space with the seats in driving position)
I know 2x8"s subs will not exactly be making alot of low end, however its all that can fit, Cleanly as least.
Car has been taped off and prepped, and disassembly started. I think I will replace a few of the stock speakers as well while I am in there.
will update my progress
Adam
Mid fuse panel all prepped stock rear drivers 3" that I will steal signal and turn on from alpine sub/amp unit, all metal construction picture showing how little space is actually behind the seats
So got all the wiring done, and then installed the two powered subwoofers. Much better than stock. Its not moving a lot of air, and you cant compare them to 10" or 12". However it adds that nice low end kick. Install went pretty clean, all the harness were loomed and heat shrinked. There is about 1/4 space left on the passenger side of free space. And on the driver side there is about 1/2 inch. You can put the seats all the way back, but its a super tight fit. If these powered subs were any bigger they would not fit. To hold it against the carpet, I used carpet tape, so the car is not molested in any way.
Nice work! Is it that simple of an install or would you need a pro to do it? Is it just a wire to both speakers from sub amp then power wire to fuse box? Is there a ground or any other wires? TIA I have the B&O system in a roadster
If you can do basic wiring and use a multi meter its simple. You have to use a fuse tap on the fuse panel to get power, ground is easy as there are great grounds on the aluminum cross member. Source signal and turn on comes from the right and left rear speakers. You just use speaker wire taps on those. You need to tap both left and right as the amp uses a combined signal. Other than that you just have to run power wire and ground wires, and speaker wires. Its all hidden behind the carpet so you dont have to make it pretty if you dont want too.The 8"s so add a nice punch to the system that it did not have before. I think the B&O system only has a pair of 6" "subs" (really those are mids) in the rear crossmember. Its a good fix for a bad sounding stock system. Most of the time is used up taking all the panels apart and protecting the car with painters tape so I did not scratch it.
Perfect!! I am going to try and do the same my self. I appreciate the detailed explanation, sounds like the hardest part is taking the interior panels off. Everything else easy
Here is a video on how to take the parts off even One thing.. when you put back the plastic parts that go around the roll hoops and sides, make 100% sure that the plastic arms that go rearward into the fold up top, go UNDERNEATH the top material, or when you try to put the top up, they will go into the wrong position on the outside of the top.
fuse tap parts , double sided tape to mount the amps , alpine amp/sub , speaker tap wires. (negative wire on the SLS is the striped one for the rear speakers) wire for power and ground
Amazing!!!! WOW Great step by step video and pics, appreciate it! Cant wait to do it. Will try and do this week as my covid project, having so much down time. Will keep you informed with process.
Last edited by renntechSLS; Dec 18, 2020 at 11:41 PM.
Here is a video on how to take the parts off even One thing.. when you put back the plastic parts that go around the roll hoops and sides, make 100% sure that the plastic arms that go rearward into the fold up top, go UNDERNEATH the top material, or when you try to put the top up, they will go into the wrong position on the outside of the top.
If my top ever needed to be replaced... I would literally try to find out who that guy is and fly him in...he’s the only one I would let touch my car 😂 That job looks like a nightmare. If he wasn’t available I think I would just drive the car off a cliff 🏎💨💨
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