Posts tagged ‘Camaro Convertible’

July 8, 2013

Speaker replacement in 2012 Camaro Convertible

It is generally accepted, at least by me, that the factory sound system in the Camaro is sub-par. The speakers are cheap, too small and the amp is also sub-par.

I did a lot of reading on the forums and internets to see what all people had done to come up with a plan and… well, make it a bit more ‘me’.

Subwoofer update:

I already covered the subwoofer installation in a previous article.  I’m not real happy with the Comp-D that is in there, it felt cheaper than I wanted, but sounded better than factory.  I stuck with it because I knew it would fit, as others have used it. *sigh* I have a new sub on order in hopes to remedy this issue. [comp-d 40CWD104 was like 86.2dB Sensitivity, new sub is 93dB Sensitivity with the same rated power handling]

For those at home chewing popcorn, 3dB increase = roughly 2x as powerful, however a 10dB increase “sounds” about twice as loud to the human ear. So, by getting a more efficient speaker it makes better use of the same power from the amp. In this case, I hope it should sound about 70% better.

Center Channel speaker:

The factory has a center channel that is powered by a horribly small (smaller than the rears on the convertible) 3″ shallow speaker.  This is a WIP, getting center channel sound from stereo L&R is a horribly huge debate but I will cover the installation of the actual speaker here.

I had a choice to heat up and drop the factory air duct that the center channel speaker rests upon or build up a little bit, as there is no reasonable driver (other than some tweeters) that one can fit in this space.  I don’t know what mechanisms may be below the duct and I don’t want to impede airflow, so I opted to go above.  This had another design goal as well, I needed status LEDs for some engine parts and they will fit there.

Center grill removal was uneventful, 4 retaining clips and two clips from the grill in the dash piece.

I made the adapter in two key parts (three sections), the outer trim and the inner stand-offs that raise the new driver just above the air duct and allow it to be screwed in.

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The outer trim was built to allow the 4 retaining clips to be used in the factory locations and thus the factory grill could be re-used. This was covered in vinyl that matches that of the dash.

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The factory grill was worked over the top of a golf ball by hand to allow a dome to facilitate the angled tweeter of the new drivers.

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The factory connectors were salvaged off all of the interior speakers by cutting them free from the plastic frame and then soldering the snapped off metal tabs to wires soldered to the new drivers.  This assured the new speakers were “plug-and-play” to the factory harness.

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Front door speakers:

This was uneventful. Mostly as see here in this person’s YouTube video; ( http://www.youtube.com/watch?v=Rmtj81AvKw4  ) There are several write-ups on pulling the factory speakers out. I recommend heating the top of the plastic frame with a hair dryer or low setting heat gun to loosen the glue and then pulling the top of the factory speaker off.  You then cut the supports with the dremel to produce a nice mount for your 6.5″ speaker. I did make a small notch above the door mounting tab, to allow the speaker wires to go through to the crossover.

The front tweeters involved using the dremel to clear part of the factory mounting circle within the tweeter cover to accept the new tweeter. I used rubber weather strip around and behind the tweeter to allow it to fit securely. The factory wiring harness was not used for the tweeter and the replacement tweeter was wired directly to the crossover.

The crossover was mounted with 3M trim tape on the front portion of the interior door panel.

 

Rear Speakers:

This, was not easy.  The factory uses 3″ speakers here within a plastic inner panel that is made to fit that speaker size.  The factory speaker sits within a stamped area of the side panel steel.  There is room here but the issue is clearance to the top, without cutting steel.  So, your option is to go out and up, within the outer plastic door panel to mount a 5.25″, use a 3″ aftermarket driver and “HOPE” that the tweeter clears the outer panel.

I did a few things with this panel that were unique, so you can expect someone to copy this and sell it shortly without giving me credit or compensation. ;o)

The most complicated aspects for my design criteria were to replicate a silver panel that looks like the front door panels and integrate a rear ABL lighting swoop that followed that curve on the top, similar to the fronts.

I got to try my hand at vacuum forming acrylic in a rather large size.  That was fun and had a few lessons along the way.

I mounted my 5.25″ drivers into the factory steel pocket by hacking a circle out with the dremel between the front panel clip areas. Then I formed an MDF adapter plate that was bolted into the bottom of the factory location for the bottom speaker screws and the tops were bolted directly into the top panel steel.  There was room there and it did not conflict with the convertible top mechanism but one should be careful to avoid it. 😉

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To make a panel:

The factory panel was placed within a garbage bag to prevent contamination.  I used a deflator pump to suck the air out of the bag and then tie it off.

EDIT: I found that it is FAR easier to eliminate wrinkles here than later. :/

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With that done, I made two stiff box the size of the panels. This was used to hold the plaster of paris mix that was used.

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I mixed the plaster up with a drill and a jug of water in a trash can. Once you start, you don’t have much time before it sets.

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Once mixed, the mixture was tossed in the box, followed quickly by the panels. I moved them in a slight circular motion to try to eliminate air bubbles under the surface and assured that the panel did not flex out of shape.

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Repeated for 2nd panel.

In a few minutes, I used a chisel to tap/cut away any plaster that overlapped the back of the OEM plastic panels.

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After the edges were clear, I pulled the panels out and threw away the bags.

Here is what I was left with;

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Now I unscrewed the edges of the boxes, so I was left with the single backboard and the plaster.

Next, I used several coats of bondo to create a raised edge along the factory “swoop” indention as well as to fill in any surface irregularities.

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This was allowed to dry and then was sanded down / shaped.

EDIT: After making my first attempt, I didn’t realize how much surface detail would be picked up. so I had to go back and re-sand the molds with spotting glaze and do a better job at sanding. I also cut back the edges of the mold and made sure the edges were all smooth.

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I did not have an “oven” large enough to heat a sheet this big.  Wind did not cooperate, either. But I did the best with what I could use.

I made a vacuum forming platform by 3 layers of heavy MDF caulked together and secured by screws. The top layer has holes in the top and the bottom has an attachment to the big shop-vac hose. This was suspended on top of two saw horses. Through this, I inserted two long carriage bolts for indexing purposes to the top.

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The top was made by two sheets of MDF and 8 carriage bolts with washers and wing nuts. This was used to sandwich the 24″ x 24″ acrylic between and lock it in place.

Now I had to make an oven to bring the plastic up to temperature.

I originally tried just an 800W IR space heater.  Not enough heat.

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I lined the inside of my patio fire-pit with aluminum foil to reflect heat and reduce air. Still not enough heat.

I used the electric element from a smoker on the bottom and the 800W heater on the top and that worked.

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Heat (even heat) is absolutely critical here.  Over heating the panel causes cracking, under heating makes it too stiff to form properly.

I then positioned the mold on the vacuum surface, heated plastic, hit the vacuum and pushed the carrier over the top.

I wound up with this:

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I used the dremel to cut the basic shape out from the sheet.

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EDIT: again, I found out through messing up one piece.  In sanding or cutting the acrylic, don’t over heat the edges, take your time or it will develop a lot of small edge cracks.

This is the cut form, overlaid on the OEM panel.

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Fast forward, I cut openings for the new speaker grills and adjusted those to fit.  I painted the insides of the panels silver (well, medium titanium metallic)

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I cut the same location from the OEM outside panel.

Then I rolled a lip around the edge of the speaker grill and used RTV to attach the grill into place.

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I let this cure over night.

Now for the light pipe, I attached my LED to the light pipe, drilled two 1/16″ holes for the LED wires to come through to the back. The light pipe was glued along the “swoop” recess with clear RTV.

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This was left to cure over night.

I used a caulk gun tube of GREY RTV to adhere the acrylic to the OEM panel (after washing them both down with plastic part surface prep to remove any oils.)

EDIT: I painted the inside of the acrylic panels and the adhesive discolored the metallic of the paint. So I will be painting the outside and shooting clear coat. (except for the light pipe).

I used some weights and tape along the edges to hold the two together and aligned while curing.

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Once this was secure, I separated the acrylic from the light pipe just slightly and used clear silicone to run a bead.  This was smoothed off on the outside.

This was let cure over night.

Finally, power was soldered in place with standard ABL connectors and a dynaohm between the loop of the two panels.  This was extended to the normal car ABL circuit in the door panels. (located within the kick panel).

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This photo is bad, the swoop goes the whole way along the panel but it did not show up. some night I will retake the photo with a better camera.

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June 25, 2013

Subwoofer installation on 2012 Camaro Convertible

I’m going to fragment up various parts of fixing the stereo in this car.  I wish they just had a “real” premium sound system from the factory so I wouldn’t have to deal with it nor have the liability of theft. But, I digress.  This article covers the way I chose to replace the stock subwoofer in the Camaro and my principles for why I did it this way.

The stock sub hardly moves, causing a dampening of low frequencies that boarder-line clips low end. But, if it did move (even the little it does)…  it is in a free-air chamber. the sub fires through a port between the seat cushion, yet the back of the sub is in a big metal chamber with holes in the front, tops, sides and back.  All of which, in the convertible, are also within the interior compartment. That is right, behind that structure is the inside where the convertible top tucks. This is bad, as all the sound waves from the back of the sub get pushed (delayed and reflected) back into the interior to mess with all the sound waves making a muddled mess rather than the one sound source you want.

JL audio has a stealth enclosure that works to defeat this issue a bit (at the cost of already rare trunk space) by placing two tens that fire in the trunk and use a port that goes through the rear wall carpet and stops at the port between the seats.  This is better… but it still has a number of air channels pounding bass waves A; the port pushes pressure waves B: the subs in the trunk make every other air opening between the trunk and the interior cabin pound waves. Oh, and they want ~900$ plus you get to cut the rear carpet and liners up a lot.

So, I took a cheaper and, in my mind, a better approach. I sealed up the left two thirds of the area behind the seat with tape, filled the other 1/3 with poly batting, then lined the 2/3 side with expanding foam sealant to prevent serious air movement.  This “kind of” gives me a sealed enclosure and should seriously assist in deadening rogue sound waves.

Incidentally, in retrospect, the car now has considerably less road noise from the rear of the car. I was a little depressed that i don’t hear the exhaust note as well as I once did. So, it does help block rogue sound transmission.

Here is the factory location:

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Love those holes! How about the inside looking at the side?

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Taping up the inside (that foam is sticky/expanding)

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I cut a plexiglass panel and used noise batting above to protect the control box.

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Poly batting filled the drivers side (which left access to the harness, including battery cables etc.)

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Now sealed up behind tape

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After the rear and sides were taped up over all connector ends, clips, and holes I applied the carefully controlled layer of Great Stuff expanding foam sealant to the rear and sides.  The front will be done after, so that we can maintain access. 🙂

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Then the front gets a light coat, followed by a protective wax paper piece.

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I let it sit a little while and cure.  Then after it is no longer sticky, I used my finger tips to carve / peel pieces out that over expanded. This left me with a nice sealed area.  Note: I didn’t make it perfect, frankly, odd textures will help disperse sound waves better than flat.

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Wala… now for the speaker.

The factory sub uses two voice coils, so it has two pairs of wires going to it.  They are plenty big for the power I’ll be pushing, this isn’t trying liquify my spinal cord.  What I did was salvage the connector from the factory speaker, took both positives together and both negatives together. I can do this because I am NOT keeping the factory Boston Acoustics amp.  This will give me twice the wire size of a single pair to my new mono subwoofer amp channel. (rocket science there).  I then attached that to the paralleled dual voice coils on the new kicker subwoofer (two 4 ohm in parallel is 2 ohm load, for the amp, perfect.)

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Well, crap. The adapter board I picked up has an air gap. Probably should have just rebuilt the factory metal plate from the original sub.

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So, rubber to the rescue!

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Now, connect to the factory harness and screw!

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UPDATE: The kicker sub was disappointing. I should have known better. It had a low sensitivity rating.  I replaced it with another driver that fits the space, has the same power rating and should sound (it does) about 70% louder, as it is more efficient.

I removed the MDF panel and used the factory metal bracket, drilled for the new mounting. The reason that I did this, is that the plastic port in the back of the seat is intended to seal / conform to that exact contour.

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