bendow

Hi all, wanted to post some pics of the sub install I did on my girlfriends C300 with the HK system. I asked a few questions on this board that weren't answered, so I figured this would be helpful for others researching a sub install.

Running the power wire
There's a video some guy did on his C300 install which was helpful...but WAY too long. He nearly took the entire car apart too...completely unnecessary. I ran Stinger HPM 4 gauge for the power wire and I taped an addition 14 gauge wire with it (about 20ft each). Remove the battery and run the wire through the rubber grommet, and then through the cable tray. You only have to remove the front/back door sill pieces and the bench seat, don't need to remove the backrest portion. The hardest part was feeding the wire through the existing cable tray between the front and back seats...coat hanger required. To remove the bottom portion of the rear seat, push in and lift up...takes some elbow grease. The wire will easily fit under the backrest portion safely. (I did end up removing the backrest portion for another reason which I'll explain later).

LOC
I used the 14ga to power the Audiocontrol LC2i. The LC2i is pretty awesome. It has "GTO" (great turn on). This means it turns on when it senses voltage through the speaker wire...no remote wire for the LC2i or amp required. It also has "Accubass" which allows you to circumvent bass roll-off from the stock stereo. I tapped the purple/brown(+) and purple(-) wires from the stock sub about 1ft away from the stock amp.

Grounding the wires
I grounded the 4ga amp wire and the 14ga LC2i wire both to the floor pan, which ended up being a decent ground. They both had a separate ground. GRIND OFF THE PAINT BEFORE GROUNDING. You can easily do this with a drill and drill bit by holding the drill sideways.

The Box
Out of the pics I searched for of a C300 with subs installed, most of them were in prefab boxes that took up the entire trunk with a single 12" box. I've yet to see a C300 with 15" sub. I saw a pic (on here I believe) of a guy on here who made a nice custom sealed fiberglass enclosure, but I didn't want to do that since I'm no pro with fiberglass. The subwoofer enclosure is much more important than the sub itself. Most prefab boxes are not made to match the subs specs.

I managed to get 3.25^ft of space after port and subwoofer displacement...AND I didn't take up the entire trunk (16.75" depth, 30" width) I used dual PSP flared ports and tuned the box to 33hz. I measured the pieces I needed and went to home depot and had them cut it. All I needed was a drill, jigsaw, screws, and glue to put the box together. I didn't use MDF as most do. I used 23/32 Arauco plywood. It's great....good acoustically, stronger than MDF, it holds screws way better than mdf...its lighter too. Be sure to pre-drill the holes for the screws. I made the front portion where the sub mounts to with 2 pieces of wood (double baffle). This provides extra strength and allows you to flush mount the subwoofer which is very aestheticly pleasing. I epoxy resin'd the entire interior, and the exterior seams to ensure it was sealed. I found some indoor/outdoor black carpet at home depot that is a very close match to the stock carpet...you have to look closely to notice a difference. I used contact cement to put the carpet on. The box is pressure mounted/secured under the deck...it's not going to move. I used a 15" sub, if someone wanted to build a box for a 12" which would require less space, you could definitely reduce the depth and retain even more trunk space. The height would be necessary to secure the box, though.

Other
The amp is an Exile 1200.1 and the Sub is a 15" Treo SSI D4. The Treo SSI is an older model, I got a great deal on it. It's way better than the JL W7 that everyone thinks is the greatest sub out there. I'm putting about 850w @ 2ohm to the sub (no light dimming). I installed second skin sound deadener under the trunk lid and the license plate. I removed the back seat and took out the foam on the rear deck....this made a HUGE difference in output from the sub.

Impressions
Night and day difference. The Treo SSI is a good sub for sound quality which complements the HK system very well. The bass is controllable through the stock interface so you don't need it making your heart stop all the time. I was at my GF's house in her garage adjusting the gains, etc, and her mom was visiting. The mom asked my GF if it was thundering..lol..so the bass is really loud if you want it to be.


This is the pic I sent to my GF when she asked how it was going...lol. You can see the cutouts in the box which make it fit all the way against the back wall.

bendow

Richie999

What does this photo represent?

bendow

the trunk? there the amp, lc2i, and wires. I cleaned the wires up after I tested and set gains. the blue and grey wires are for the sub

stogge

Wait, you put the amp in the spare tire well?

Without ventilation, sounds like a fire hazard for sure...

bendow

Where do you think would be a better place? In the trunk mounted directly against the carpet? The trunk doesn't get much ventilation either, in addition, the trunk is completely covered in carpet. Amps overheat quickly when naive installers mount amps directly to carpet without any type of spacers.

I put a 3/4" spacer between the amp and the spare tire. There's about 2" of space between the top of the amp and the trunk floor. The way the amp is mounted, it's using very little surface space, and the surrounding space is metal. Also, fuses, and the protection mode on the amp provides peace of mind as well. I've seen others mount their amps in the same location in C300's.

Exile Amps run cool anyway. I have an 2400.1 and an 800.4 on my boat. The 800.4 will run 100x8 @ 2ohm, in 100+ temps on my boat at full tilt and doesn't overheat....I couldn't imagine the 1200.1 Class D amp that's 1ohm stable, running at 75% capacity @ 2ohm having overheating issues.

lemzen

spacers? ive installed many types of stereos in many types of cars and ive read many manuals. the manuals that i have read, say not to install under the seats or under anything with less then a few inches and space from the amp, never have i seen them recommend or have i used spacers. unless you build a fiberglass unit, everyone mounts amps directly to the carpeted box or the carpeted trunk floor or wall. i have never seen any over heating problems or fires due to the carpet under the amp. what i have seen was overheated amps due to covering the amps with crap or not enough ventilation. if your gonna put it in the spare tire well at least take the tire out and give it some more room to breath, plus you should clean those wires up, not only does it look bad but that will cause sound problems if you have power and audio wires bundled up with each other (not saying you do, i cant really tell but just fyi).


anyway, do you have folding rear seats, does the trunk muffle all the sound and how is the rattle around the car?

bendow

hmmm...it kind of seemed like you contradicted yourself. You questioned my use of spacers, and then told me the amp needs room to breathe. Do you think an amp only needs to breathe on the top? Heat needs to dissipate from the top as well as the bottom. Having an amp mounted directly to carpet will trap heat and increase the chance of it overheating. I can assure than chances of the amp overheating where it's mounted now are significantly less than it would be if it were mounted to carpet in the trunk. Now, if I mounted it in the trunk with spacers that would be the best option, but I didn't have the room.

You mentioned everyone you've seen mounts amps on the box, apparently they haven't heard of box rise. Mounting an amp to a subwoofer enclosure is also bad idea.

I know the wires are a mess in that pic, but like I mentioned earlier, I cleaned everything up after I set the gains, subsonic filter, lpf, etc.

I assume you're referencing my speaker wires being next to the power wires and causing sound problems? Speaker wires are high voltage meaning the likelihood of noise from EMI is minimal at best. Now RCA's are a different story....

My girlfriend doesn't have folding seats. Bass is low frequency, so it wouldn't say it was muffled. The output increased substantially after I removed the foam from the back deck. The trunk did rattly quite a bit...the second skin sound deadner solved that issue.

Richie999

(Just some fun here.....)

So heat does not rise in your community?

wnunez89

i had my amp in the same area at first it was fine no issues, moved it later to the back of the seat frame, only moved it bc i put a yellow top in its place, im sure the amp has an auto shut off if it starts to over heat anyway so it should be no biggie.

wnunez89

oh btw looks good, thinking of adding a digital design 9515" or a Rockford fosgate 15" in my 350.

bendow

.ok...I just wanted to share my install and tips with others, not defend every aspect of the install. I don't even have a C300 anyway....

bendow

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cool man, I really like DD, but you're going to need a lot of space for a 9515. They like big boxes. Id go with a 12 if you want dd or another brand if your set on a 15. I personally like sundown...the 15 Z is amazing and does well in small boxes...

jimmythegreek

guys its for his GF, she got a sweet deal out of it, cause I know Im not doing a sub/amp for my old lady....haha......anyway for future the best place is under the rear deck in these cars and yes you should use spacers, just use rubber feet or from the plumbing aisle in home depot. I always use the plumbing washers there are some 3/4" thick w a hole in them already, I had to use them in the 2011 cause the folding seats have a cable on the deck and you have to be off the deck a little to clear it. either way nice job and I also removed the foam on the rear deck and ported into it, sounds way better in cabin and reduced trunk vibes

wnunez89

yeaa ive been using DD for my last couple set ups, i already had a 2512" so i wanna do something different and ive never done a 15" so im pretty set on that, but yes the box is gonna be huge lol, probably a pwk design box

IllusionX

Whats the hook up look like? I checked out the Lc2i and I see it has the remote in/out, ground, power etc. I'm looking to hook something up, did you tap off the original sub or back speakers? Sorry for asking so many questions. Can you explain what you have hooked up to what? Thanks.

stogge

Loooks good, I'm sure it pounds! I had just never seen an amp installed like that, but hey if it works, thats awesome! Good Work!

bendow

I tapped of the speaker wires for the stock sub. I tapped the wires about a foot after the amp. She has the HK system, so I'm not really sure where you would tap the wires on the regular one, if that's what you have.

I ran 4gauge power wire and a 12gauge wire together from the battery to the trunk. The 4gauge is for the amp, and the 12gauge for the LC2i. (12gauge is a bit overkill. 16 will do just fine). There a 150a inline fuse next to the battery on the 4gauge and a 5amp on the 12gauge. The LC2i and the Amp are both seperately grounded to the trunk pan with equal size wire.

The 2 speaker wires I tapped go to the +/- on the LC2i. When the car turns on and off so does the LC2i. It senses the voltage from the speaker wires and turns on itself, and then it's remote output turns the amp on. No need to tap a remote turn on from the car. The remote output from the LC2i goes to the remote input on the amp. The LC2i has a remote input, but you don't need to use it. 1 pair of RCA's go from the LC2i to the amp. Hope that helps.

I took a better pic. I was pleased to get a 3.25^ft net enclosure and still have some usuable space in the trunk. My GF drives like a maniac and the enclosure hasn't moved, so the pressure mount idea worked as planned.

bendow

Well good luck man...I'm sure you won't feel like you're missing any bass with that 9515...lol.