MDF Speaker Cabinet Primer
(NOTE: Products mentioned in this document may no longer be in stock. This is to be used only as a rough guide.)
By using technology previously only available to high end speaker manufacturers, you
can now build an audiophile quality speaker system without the need of
expensive woodworking tools or hours of labor. These cabinets are precision
milled with a CNC router to incredible exacting tolerances. Dado and slot joinery
are used throughout to provide incredible strength. The cabinets are made of 1"
MDF (medium density fiberboard) to reduce cabinet resonance and coloration.
Driver selection/Cabinet tuning
The cabinets come with pre-cut baffles that will accommodate a variety of
standard drivers. If you want to flush mount your speakers or use odd sized
European drivers and have access to a router with a circle cutting jig, a blank
baffle is available. See "Optional Blank Baffle" for instructions on routing
your own driver holes.
The box sizes were selected because they suit a broad range of drivers. Using
Bass Box (#500-923) or another speaker design software, enter your drivers
Thiele/Small parameters and lock in the appropriate internal cabinet volume.
Adjust port diameter, port length (if designing a vented system) and the amount
of box stuffing to fine tune your system for optimum performance.
Assembly Instructions
Tools And Materials
These cabinets were designed to be easily assembled using ordinary household
hand tools. The following tools and materials are required to complete the
project:
1) Paint brushes to apply glue and finish
2) Polyurethane glue (recommended) or Carpenters' wood glue
3) Electric/manual screwdriver and drill bits or hammer with nail set
4) Wood screws or finishing nails
5) Wood filler and putty knife
6) Silicone sealant to seal terminal cup, port tube, etc.
7) Sand paper, 100 medium grit, 220 fine grit and sanding block
8) Contact cement (if applying veneer or laminate)
9) X-acto or utility knife (if applying veneer)
10) Veneer, laminate or paint for finishing
The following tools are optional but recommended:
1) Adjustable bar clamps
2) Orbital palm sander
3) Router with circle cutting jig (if using blank baffle)
4) Compass and ruler (if using blank baffle)
Assembly of the cabinet
Your assembly area should be clean and protected with cardboard or
newspaper.
Carefully unpack the cabinet pieces and check for shipping damage. Take care
not to damage the ends and corners of the wood pieces while handling. The
dado and rabbet cuts on the MDF material are vulnerable to nicks and damage
until they are assembled. If you are building a vented cabinet and using a
speaker grill kit, now is the time to cut the port hole and drill the holes for the grill
guides (see "Final Assembly" for information about installing speaker
grills).
Assemble (without glue) all wood pieces to ensure proper fit and to familiarize
yourself with the assembly of the cabinet. We've found that the following
assembly sequence works best:
1) With the back piece flat on the table, insert brace(s) into its dado slot(s).
2) Align each side panel with the back piece and brace.
3) Insert top and bottom pieces.
4) Install the front baffle.
Note: If you are building a subwoofer enclosure, the kit will include wood pieces
to build a pedestal for the cabinet to sit on. Simply position the wood pieces to
form a square and fasten them together using glue, screws or nails. Finish the
pedestal in the same manner as the cabinet.
Gluing
We recommend using polyurethane adhesive with the MDF material because polyurethane adhesive naturally expands to fill gaps where wood glue does not. If
polyurethane adhesive is not available, a quality carpenters wood glue will do.
Follow the glue manufacturer's directions and apply to BOTH SURFACES of all joints and assemble
the cabinet as described above. Use fasteners or bar clamps to hold the cabinet
together while the glue dries. Remove all excess adhesive and allow to set
overnight.
Fasteners
If you have access to bar clamps it will make the assembly of the cabinet easier.
If not, you will need to hold the cabinet together with screws or finishing nails
while the glue sets. Keep in mind that the glue and joinery provide the structural
strength, not the fasteners. If you use wood screws, they will need to be counter
sunk below the surface. Pre-drill all screw holes using a bit that will drill the pilot
hole, shank and counter sink in one operation. Remember that for every screw
you use, the hole will need to be filled with wood putty and sanded. The box can
also be held together using brads from a pneumatic nail gun or regular finishing
nails. Use a nail set to recess all nail heads below the surface. Because the
finishing nail leaves a smaller hole, it is a lot easier to finish especially if you plan
on painting your cabinet.
Surface Preparation
The amount of surface preparation needed depends on how you plan to finish
your cabinet. If you plan on painting your cabinet you will need to spend more
time preparing the surface for paint.
1) Fill all screw/nail holes and other imperfections with wood filler/putty using a
putty knife and let dry. Note: Due to shrinkage of the wood filler, you may need
to apply several coats.
2) Sand the cabinet using 100 grit medium sand paper with a sanding block or
preferably, an orbital palm sander. Sand the wood putty until it is smooth and
blends in with the surface. Note: Use caution when sanding around the edge of
the cabinet to keep from rounding the corners.
3) After sanding is complete, clean off the remaining dust with a rag moistened
with mineral spirits and let dry.
Optional Blank Baffle
When laying out the location of the drivers on the blank front baffle, there are a
few items to consider. First, the drivers, particularly the tweeter, should be flush
mounted to minimize diffraction effects. It's amazing how much smoother the
tweeter's frequency response is by simply flush mounting it! Because of this, we
recommend using a router with a circle cutting jig to cut the driver holes. The
Jasper circle cutting jig (#365-250) makes cutting and recessing driver holes fast
and easy.
1) It is a good idea to first mark the location of the internal brace on the front
of the blank baffle. This will ensure that your driver holes do not conflict with the
brace. In most cases, you will want to center the drivers (left to right) on the
baffle. If so, draw a line down the center of the baffle.
2) Next, measure all pertinent driver dimensions (inside / outside diameter,
faceplate thickness, depth, etc.).
3) Using a compass, draw the outside diameter of each driver first, then
draw the inside (hole) diameter. Note: If you are building a vented box, you will
need to allocate space for the port hole.
4) When driver placement markings are complete, use a router with a circle
cutting jig to cut the driver holes. You should always cut the outside diameter first
and then work inward. When cutting the recess for the drivers, add 1/16th of an
inch to the depth for caulk or sealant.
Tip: It is a good idea to make sure that your crossover will fit inside the driver
holes before installing the front baffle. Also, if you plan on using a speaker grill,
now is the time to drill your holes for the grill guides.
Cabinet Finishing
There are a number of ways to finish your loudspeaker cabinet. The possibilities
are virtually endless! Generally, the most popular way is to veneer, stain and
varnish the cabinet. You can also paint the cabinet, but this requires a lot more
surface preparation to achieve satisfactory results.
Veneering
1) Make sure the surface is clean and free from all dust, cracks etc.
2) Lay veneer flat to remove all ripples and allow veneer to reach room
temperature before proceeding.
3) Cut all veneer pieces 1/4"-1/2" oversize. Tip: To make the grain wrap
around the cabinet, layout the veneer pieces in the following order: side, top,
side and bottom.
4) Apply contact cement as smooth as possible to the cabinet and veneer.
We recommend using Bostik contact adhesive spray (#341-855). Allow both
surfaces to dry completely before applying veneer. Apply cement to one
cabinet side and veneer piece at a time.
5) Start in the middle or end of the piece and make certain alignment is
correct. Working from the center outward, applying even and firm pressure
on the veneer face to insure proper bonding. Make sure all air bubbles have
been removed.
6) Trim excess veneer using a new sharp blade held at a 90 degree angle.
7) Repeat procedure until all sides are veneered and allow to dry overnight.
8) Lightly sand the entire cabinet using a 220 grit fine sand paper with a
sanding block. Note: Use caution when sanding the veneered panels. The
veneer is very thin and only requires very light sanding. When sanding is
complete, clean off the remaining dust with a rag moistened with mineral
spirits.
9) Stain the cabinet with the stain of your choice following the manufacturer's
directions. Allow to dry.
10) Apply one or two coats of the desired varnish or polyurethane. Again, follow
the manufacturer's directions.
Painting
You can paint your cabinet, but this requires a lot more surface preparation to
achieve satisfactory results. Please keep the following in mind if you attempt to
paint your cabinet.
1) Take your time! Do not rush through the surface preparation.
2) Use a quality sandable primer and apply several coats. Use 220 grid fine
sand paper and sand between each coat. Tip: If you use Krylon lacquer
based primer, you can use red automotive "spot putty" to remove any major
imperfections that you find after your first coat of primer.
3) If you use a glossy finish paint, any imperfections in the surface will show
up.
4) Use a quality paint and apply several coats (we recommend Krylon brand
because it is a lacquer based paint and provides an excellent durable finish).
5) Follow the paint manufacturer's directions.
Final Assembly
Terminal cup: All cabinets (except subwoofers enclosures) have a cutout for our
terminal cup #260-307. This terminal cup is a pressfit design. Using a hammer
and a block of wood, gently tap the terminal cup in place. Note: It is a good idea
to attach the wiring to the cup before installation.
Sealant: Using silicone sealant (#341-805), seal around all internal cabinet
joints, terminal cup and port tube. Let sealant dry.
Crossover: Hook up all wires to the crossover and install it inside the cabinet
using short screws (less than 1"). Run wires to driver locations.
Acoustic foam: We recommend that you line the interior of the cabinet with
acoustic damping foam (#260-315) It absorbs internal standing waves inside the
cabinet and prevents reflections to the woofer cone. Cut the foam to fit internally
on the right and left side walls, rear, top and bottom panels. Do not apply it to
the front baffle. Also, make sure it does not obstruct the air flow to the port tube,
as this will alter the tuning of the box. Measure the areas to be covered and cut
the foam slightly larger so that it can be pressed or squeezed into place. Spray
adhesive (#340-255) may be used to secure the foam in place.
Mounting drivers: Hook up the wires to the drivers while observing correct
polarity. Using speaker sealing caulk (#269-300) mount the drivers to the baffle.
We recommend using T-nuts and machine screws (#260-775) for driver
mounting.
Speaker Grill Kit: If you want to have grills for your new cabinets, we offer a
Speaker Grill Kit (#260-333). This kit is easy to assembly and can be cut to any
size. It comes with grill guides that mount to the front baffle. We also stock grill
cloth in a variety of colors (black, white, brown and dark gray). The grill cloth
attaches easily with spray adhesive (#340-255)
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Springboro, Ohio 45066 |
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