Speaker Cubes -a hifi upgrade to your TV
Projectors and flat screen TVs are pretty cool, but the
horrible speakers built into them are only cool if you really hate your
ears. In this small project I build a pair of self-powered speakers
that can connect to anything, and make a great upgrade for a TV.
- 2'×4' sheet of particle board
- 2'×4' sheet of thin lauan plywood
- Wood glue
- About ½ yard of sheer nylon fabric
- Two 5" speakers
- Panasonic AN17147 amplifier IC (or equivalent) and
Start by laminating
the plywood onto the particle board with wood glue, weight it down and
let it set overnight. Cut your new composite board crosswise into
several strips 6.5" wide. For this next part, it really helps if you
have a table saw. Set your saw's rip fence to 6.5" and set the blade at
a 45° angle. Cut your strips into eight 6.5" squares, with bevels
on three of four sides. This takes care of all four walls of both of
your cabinets. Cut
two more 6.5" squares with a 45° bevel on all four sides, this will
be the back panel of the cabinet. Assemble the five parts of the
cabinet with a liberal application of wood glue and clamp it together
overnight, or use a few small finishing nails to hold everything in
place until the glue sets up. Wipe off any excess glue with a damp
sponge immediately, especially if you're going to stain the cabinet,
since stain won't absorb into wood glue. You should now have a nice box
with an open front.
we need a front panel. Take a small piece of unlaminated
particle board and cut it into a 6.5" square. Use a table saw or router
to give the panel a decorative edge. I used a 45° chamfer, but a
roundover will work here as well. If your speakers came with a
template, tape it to the dead center of the panel and cut out the
opening with a jigsaw.If you don't have a template, you can use
aluminum foil to make one, take an impression of the front of the
speaker with the foil and use it to cut out a hole the same size as
your speaker's face, sans mounting flange. Use
a router with a roundover or chamfer bit on the front of the opening,
this is mainly a cosmetic thing, since the hole will show through the
fabric covering unless it has smooth edges. When you're done, paint it
black with acrylic paint, so that it won't show through the fabric
the fabric around the front panel and staple it in
with the corners, then put staples all the way around the outer edge.
Fasten your speaker to the inside of the front panel with at least four
½" screws. Now that the front panel's finished, we're going back
to the rest of the cabinet. Fill any gaps in the corners or nail holes
with wood putty. Sand everything with 80 grit sandpaper, followed by
120 grit sandpaper, followed by 220 grit sandpaper. I painted mine with
a coat of Rustoleum Metallic black, but you can use an oil based wood
stain instead. Finish up with three topcoats of lacquer, giving each
coat a rubdown with #0000 steel wool once it dries. Once everything's
finished, drill a 1.5" hole in the exact center of the back of both
cabinets, this is the bass port. Round the edges with a router, if you
have one handy. Drill a small ¼" hole near the bottom of one of
the cabinets and slip a cable terminated with an RCA jack through the
hole, and secure it with an electrician's knot. Solder the speaker to
this cable, and glue the front panel on with a liberal dose of hot
glue. Your passive speaker is now finished, so set it aside for now.
other speaker will contain the amplifier, so we'll have to
get more elaborate here. Drill a 1" hole at the middle at the bottom of
the cabinetfor the volume control and external speaker connector, then
drill a ¼" hole on each side at the bottom of the cabinet. Slip
a power cord through one hole, and an audio cable terminated with your
plug of choice (RCA plugs, or a headphone plug) through the other one.
Secure both with a knot. Solder the power cord to the fuse holder, and
the fuse holder to the power transformer, and mount them both to the
inside of the cabinet out of the way of the speaker. Skip this part if
you want to use an external wall-wart power supply.
the amp board according to this
schematic, and solder stranded leads
about 8" long to the audio inputs and outputs. I built my amp
point-to-point on perf board, which is available at Radio Shack for a
small price. Cut a thin sheet of plastic or sheet metal about
2"×3" and drill two holes, one for the volume control and one for
the connector for speaker 2. After you've soldered the proper leads to
the volume control and speaker connector, mount the little mini board
on the back of the cabinet with a few wood screws. Mount the board
somewhere inside the cabinet where it won't be touching the speaker, I
used plastic spacers and some hot glue. Now all you have to do is
solder the leads to the speaker, and glue the front to this cabinet the
same way you did the last one.
Overall, I'm really pleased with these little speakers.
only took me about a day to build these, and cost me about $10 for the
wood. Everything else I already had on hand. If you'd like to build a
set for yourself and need to buy the materials, take a look at my resources page for a list
of trustworthy suppliers. All of the parts should come to less than $35
These are no substitute for a real stereo, of course,
they're an order of magnitude better than the speakers in my TV, with
plenty of bass and a much more fluid sound. Being as small as they are,
they're also quite portable, and since they're self powered you can
plug anything into them, CD player, satellite receiver, tape deck, MP3
player, whatever you have. You can even listen to the music channels
without having to turn the TV on. If you liked this project, you may
also like my Cirrus Logic hi-fi DAC and my homemade computer speakers.
The back of the finished cabinet. You can really see the metallic
Another view of the assembled cabinet.
This is the front panel after I machined and painted it. Note the
chamfered edge around the opening.
These are the little full-range drivers I used.
I've mounted the drivers to the front baffles with small wood screws.
This is how you attach the fabric to the front baffles.
Front of the fabric covered baffle.
A view inside the cabinet. The power transformer is at top right, the
fuse holder is at the bottom, and barely visisble to the left is the
Another view inside the cabinet with the amp board installed.
The finished product sitting next to the TV in my office. Yes, I have
an orange room in my house. Who doesn't?!
This is the back of the active speaker, showing the volume control and
connector for the other speaker.