Subwoofer Install Question
I'm going to add a sub that I had from my previous car into my 06 c230 this weekend so of course MBWorld would be my first stop. I searched for a few days on this and found a lot of threads, but the portion for running the power to the battery is what is eluding me. I did see one install where the poster recommended removing the plate underneath the glove box, where I can find four holes that go through the side wall. My only problem is that I looked at the hole and there's now way 4 gauge wiring is fitting through there.
I'm running a single 10" JL W3v3-4 and I really don't feel comfortable running 8 gauge wiring to that.
I also saw another post where the poster ran the power to the stock amp under the seat and tapped that for power, but that doesn't sound too safe either.
My question is, to those who have added subs with 4 gauge wiring... what's the safest and easiest way to get the 4 gauge wiring through the firewall.
Thanks!
I'm going to add a sub that I had from my previous car into my 06 c230 this weekend so of course MBWorld would be my first stop. I searched for a few days on this and found a lot of threads, but the portion for running the power to the battery is what is eluding me. I did see one install where the poster recommended removing the plate underneath the glove box, where I can find four holes that go through the side wall. My only problem is that I looked at the hole and there's now way 4 gauge wiring is fitting through there.
I'm running a single 10" JL W3v3-4 and I really don't feel comfortable running 8 gauge wiring to that.
I also saw another post where the poster ran the power to the stock amp under the seat and tapped that for power, but that doesn't sound too safe either.
My question is, to those who have added subs with 4 gauge wiring... what's the safest and easiest way to get the 4 gauge wiring through the firewall.
Thanks!




I have a huge install in my C240. happy to share. Yes 4 gauge fits thru the grommets.
here are some pics. Just attach the cable to the battery post connection. I tried to connect it to the fuse distribution block by the battery. No can do. The pic of the amp tray is old. I have 3 amps now on 2 decks with a JBL MS8.

How much wattage are. You running? 8 gauge should be sufficient for a single amp.
Attachment 226747
Attachment 226748
Attachment 226749
I have a huge install in my C240. happy to share. Yes 4 gauge fits thru the grommets.
here are some pics. Just attach the cable to the battery post connection. I tried to connect it to the fuse distribution block by the battery. No can do. The pic of the amp tray is old. I have 3 amps now on 2 decks with a JBL MS8.
sweeeet! did you build that tray yourself?
Right now I am running a 600 watt Pioneer PRS sub amp driving the DLS 10 inch sub. a 2x300 watt PRS amp for the DLS Nobelium mids, and 4x 75 watts for the DLS Tweets tweets and rears. awesome stuff. The C Class is so very quiet inside and the doors dont rattle at all
I also opened up the audio unit and solderd RCA outs to the pc board right after the DSP/DAC outputs.
How much wattage are. You running? 8 gauge should be sufficient for a single amp.
Yes 4 gauge fits I have it. the grommets are quite flexible. Use some lube. I used dishwashing detergent.. but hey. KY would work too!
Do I need to take a picture to prove it?
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To install a sub amp in the rear you do not need to run a wire from the battery through the fire wall under the carpet to the trunk. There is no commercial 12 volt amp that can consume the current supplied by an AWG 4 wire.
The factory runs an AWG 8 wire from the battery to the fuse block in the rear that is properly protected. I cringe when installers run a wire from the battery terminal directly to an amplifier. They have no experience with wire or circuit protection, and it make the car a prime candidate for a car-be-que on Interstate 10.
The terminals on the amps and the wire terminals commonly used cannot use the ampacity of an AWG 4 wire. Your hearing cannot stand the SPL produced by a "1,200 watt" amp. Thankfully the ratings in automotive aftermarket sound equipment are more inflated than mpg figures on a window sticker.
You can tap the power in the back, properly protect the wiring, and still have enough hip-hop thump to annoy drivers four cars back.
The factory runs an AWG 8 wire from the battery to the fuse block in the rear that is properly protected. I cringe when installers run a wire from the battery terminal directly to an amplifier. They have no experience with wire or circuit protection, and it make the car a prime candidate for a car-be-que on Interstate 10.
Fyi the 12v wire gauge charts found online aren't very consistent. The amperage ratings of 8AWGwire at 10' range from 30A-150A in these examples:
http://www.engineeringtoolbox.com/am...uge-d_730.html
http://www.hifisoundconnection.com/S...e_Speaker-Wire
http://www.rowand.net/Shop/Tech/WireCapacityChart.htm
http://www.offroaders.com/tech/12-vo...gauge-amps.htm
I have a couple of photos of the back of my SAM showing where the 12v power cable enters the unit, and a set of external fuse taps on the bottom (17-19) that are rated at 20A each.
I would venture to say from these photos that the power cable looks more like 4AWG than 8 ... it's a good 1/4" diameter. The fuse ratings on the installed fuses for this SAM (third photo) show a total of around 200A, and adding in the empty slots, closer to 300A. Are you sure this isn't a 4AWG power feed?
So ... if the battery power cable to the rear SAM is a good enough source of power, what is the best way to tap into it?
Do you suggest tapping into the cable itself before the SAM? Or using one of the designated external fuse locations (17-19 in my case) located at the bottom of the SAM? What I don't know is if these external taps run through the SAM logic board or if they are just directly connected to the incoming power cable ... I would only want to use them if the latter were true).
Thanks. John
Last edited by jkowtko; Mar 31, 2013 at 09:23 PM.


Thanks in advance
Since I ended up running new speaker wire for my Hertz door speakers, I also ended up running an 8AWG wire from the battery down the right side of the car. All is great though. I've had the stereo blasting ever since, 10W3D4 sub in the trunk, and enjoying my music!


Great to here everything worked out btw
Since I ended up running new speaker wire for my Hertz door speakers, I also ended up running an 8AWG wire from the battery down the right side of the car. All is great though. I've had the stereo blasting ever since, 10W3D4 sub in the trunk, and enjoying my music!
Not that it will help, but FYI I found this sub position to have the least amount of bloated resonance in my trunk.

Coincidentally it's directly under the pass-thru vent area so it allows a bit more of the bass to enter the cabin. I plan to build a custom box there to tuck the sub under the ledge and further forward towards the rear seat, and box it in to prevent sound from getting into the rest of the trunk where it will just resonate. And if that goes well I may try upping it to a 12".


Not that it will help, but FYI I found this sub position to have the least amount of bloated resonance in my trunk.

Coincidentally it's directly under the pass-thru vent area so it allows a bit more of the bass to enter the cabin. I plan to build a custom box there to tuck the sub under the ledge and further forward towards the rear seat, and box it in to prevent sound from getting into the rest of the trunk where it will just resonate. And if that goes well I may try upping it to a 12".






