DIY Network

Acrylic Subwoofer Enclosure: Glue-Up and Amp-Wiring From "Tricked Out" episode DTRK-113

	BEFORE. The Celica's old speaker box.
	AFTER. The new acrylic subwoofer enclosure.

In this episode of Tricked Out, host Andrew Totolos installs an acrylic subwoofer-enclosure on a Toyota Celica. In this third segment, Andrew secures the speaker-enclosure's acrylic panels with a special gluing technique and then wires the amplifier to the new speakers.

Materials used in this episode:

10" subwoofers
3/4"-thick transparent acrylic, precut to fit your design
Speaker wires
Terminal plates
Wire connectors
Straight-edge
Measuring tape
Pencil
Jig saw
Several fine-tooth jig-saw blades
Drill and bits
Hole saw
Clamps
Masking tape
Methylene-chloride acrylic glue
Syringe applicator

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	Figure A
	Figure B

Gluing the Acrylic Panels

Now that the speaker box has been assembled and secured temporarily with tape, Andrew uses acrylic glue to permanently bond the box together. While the glue cures, he'll mount the amp from the original speaker box for use in the new system.

The cement used to secure the acrylic pieces together is actually a solvent known as methylene chloride. The way it works is by "melting" the acrylic surface at the joint and fuses the adjoining pieces together.

• Take the glue applicator and apply a small amount of glue along each bottom horizontal seam (figure A). Be careful not to spill or drip any glue onto the surface of the acrylic as it will burn into the surface of the acrylic and cause a permanent mark.

• Start at an inside corner and move the applicator slowly along the edge to make sure that the glue is being sucked down into the seam (figure B). Having clear acrylic really helps so you can see if all of the joints are secure.
  

  Andrew Totolos glues the clear panels of the speaker enclosure using acrylic glue. Here he applies glue to the seams on the outside of the box.

• Now go to the outside of the box and apply more glue to all of the bottom horizontal seams. Work around the tape. After the glue sets you can peel it back and catch any missed spots.

• Add a dab of glue to tack the edges where the top meets the sides so that when you flip the box it has a bond. If the glue runs, just wipe off the excess with a paper towel as quickly as possible.

• Tricked Out Tip: Use jeweler's rouge to buff out any solvent marks left on the acrylic.

• When all of the horizontal seams are glued, let the box sure for 20 to 30 minutes before coming back to do the rest.
  

  Figure C

• After the box has had some time to cure, carefully turn it so that the speaker holes are facing you and glue the remaining joints. The glue works best when you work the joints while they are horizontal -- so that the gravity helps the capillary action and the glue does not run down the sides of the box. Just keep turning the box and gluing the bottom seams on all of the sides (figure C).

• Gluing the top is a bit trickier. Set the box on a piece of wood and allow the speaker hole to hang over the side so you can get to the middle partition and the inside top of the box.

• Once the glue has dried, you can remove the masking tape. Be sure to leave the protective paper on, though, because there's still some work to be done on the box.
  

• When it comes to mounting the amp, before you attach the amp to the seat, hook up the positive lead, the remote turn-on wire, and the ground (figure D). Then slide the RCA connectors from the head-unit onto the amplifier's inputs (figure E).

  Figure D

  Figure E

  
  

  	Figure F
  	Figure G

• Speakers and Ohms: In audio applications, electrical resistance is measured in ohms. Lower resistance means that more power is delivered (or, said another way, power is delivered more efficiently) from the amp to the speakers. The speakers we chose are rated at 4 ohms (standard for most car-stereo speakers), but the amplifier we're using can run at 2 ohms. So we opted to bridge the stereo signal into one mono signal, so that the system will essentially drive the new subwoofer as a single, large 2-ohm speaker -- resulting in greater power-delivery for bigger bass-response.

• Important: The description below outlines how we created the bridge in this particular application. Check the installation guide for your amplifier for specific bridging options with your equipment.

• Instead of hooking the speakers up to the amp in the usual manner, twist together the negative leads from both speakers and connect the twisted pair to the negative "bridged" terminal on the amp (figure F). Then twist the positive leads together and connect them to the positive bridged terminal on the amp.

• With all of the wiring in place, gather the wires and use a zip-tie to hold them together as you fasten the amp to the seatback.

• Use short screws and a cordless drill with screwdriver attachment for fastening the amp (figure G).

• With the amp secured, cut the zip tie loose, and the amp install is complete.
  

Safety Alert: Always wear eye protection and ear protection, and follow proper safety precautions, when working with power tools or pneumatic tools. Also wear eye protection any time you are working underneath a vehicle.

Safety Alert: As a standard safety precaution, always disconnect the vehicle's negative battery cable before you begin work on any electrical or mechanical components.

RESOURCES :

Crutchfield Car Audio
Crutchfield is not only a catalog retailer specializing in a wide array of popular audio equipment, they excel at providing information and resources for audio-system installation by car owners. Their Crutchfield Guide: Car Stereo Installation offers valuable information on installation of components in most vehicles. Their free catalog offers advice on selecting the best type of system for your tastes and the most suitable equipment for your vehicle.
Crutchfield Corporation
Website: www.crutchfield.com

Auto Audio
Model: 0071346899
Author: Andrew Yoder
Publisher: Tab Books
Order this title from Amazon.com.

Sport Compact Bolt-On Performance Guide: Import Cars (Sport Compact Bolt-On Performance Guides)
Author: Joe Pettitt
Order this book from Amazon.com.
Voyageur Press (October 2000)
ISBN: 1884089526

Special Resources for Tricked Out, episode 113

Stillwater Designs/Kicker
Website: www.kicker.com

Racing Innovations, Inc.
Website: www.racinginnovations.com

The12Volt.com
The 12Volt.com is a specialized website devoted to providing technical information for mobile electronics installers as well as professional tips and tricks. Included are a mobile electronics glossary, charts, diagrams, specs, calculators and general information on car-audio, security systems, cruise control and other automotive electronics systems.
Website: www.the12volt.com