In this Instructable, I will go through how I went about making this multi-purpose tower speaker/soundbar.
I got the inspiration from Kirby, who makes interesting looking speakers and posts videos of his build on Youtube.
Be sure to check out his website kmakits.com and his Youtube channel.
I used the following tools and materials for this project:
Random Orbital Sander
3/4" Pine Panel
Old Pair of Bookshelf Speakers
Step 1: Understanding Your Speakers and the Enclosure
I had a pair of old bookshelf speakers that I wanted to use for this project.
There is a lot of science behind how big your speaker enclosure should be and it depends on a lot of parameters.
These parameters are usually provided by the manufacturer of the speakers, but I was unable to find out any useful information about my speakers, so I made an educated guess (weeks of thinking and scratching my head) and calculated the volume of the enclosure based on my assumptions. (I went with a sealed design, and matched the dimensions of my bed's headboard - where I intend to place my soundbar)
If you are building your own speaker enclosure, be sure to do lots of research of different types of enclosures (ported, sealed, bandpass, etc. etc.), as the wrong enclosure volume and port length can cause inefficiency of your speakers, horrible sound quality and possibly damage to your speakers. There are lots of websites online that calculate the volume of your speaker box depending on what values you enter.
For the circuiry, I used a 24V 240W power supply, a 200W audio amp, a preamp, a bluetooth module and 2 step down converters to convert my 24V to 12V and 5V to power my preamp and the bluetooth board. (See 3rd picture. Note: this diagram only shows the power wiring, and not audio. The audio cable should go from the Bluetooth module, to the preamp, to the amp and then to the speakers.)
Step 2: Cutting Out the Sides
With a table saw, I cut the wooden panels at a 45 degree angle for the frame according to the dimensions of my design.
The outside dimensions of my soundbar were 104cm x 14cm x 17cm.
The masking tape prevented creating chipped cuts on my table saw.
Step 3: Creating Rabbet Cuts for Front and Back Panels
Using a router with a straight bit, I created rabbet slots so that once the side panels are assembled, the front and back panels of my soundbar could sit inside.
Step 4: Making Holes for the Full-range Driver
I needed to create 12.5cm diameter holes for my full-range drivers.
I thought of creating a circle cutting jig fo my router, but it turned out that the center of the hole I wanted to make lied in the middle of my router base, which meant that I would have to drill a hole through my router base.
So, I thought of an alternative.
I didn't have a hole saw of that size, so I used a rabbet bit on the router to enlarge a smaller hole that I was able to drill, and then finished it with a flush trim bit.
My rabbet bit cut 0.95cm of material around the inside edge of the wood, and since that meant my hole would end up 2 times 0.95cm (1.9cm) bigger than the previous hole, I subtracted 1.9cm from 12.5cm repeatedly until I reached a value that was closest to my available drill bit size. See picture 3 for illustration.
In picture 6, you can see the hole getting larger with each iteration of rabbet cuts.
In picture 7, you can see that once the hole became the desired size, a flush trim bit was used to trim off excess wood.
In picture 10, I pre-drilled the holes for the screws that will hold the driver in position.
Step 5: Creating Holes for the Knobs and the Power Button
I wanted to use 4 knobs to control the bass, treble, balance and volume of the sound, so I drilled a 1/4" hole for the potentiometer knobs to poke through, and created countersink holes with a forstner drill bit for the knobs to not protrude out as much from the frame.
Picture 3 shows where the potentiometers will sit,
picture 4 shows where the knobs will sit, and
picture 6 shows the power button (and the center punch dimples for the bluetooth function buttons).
Step 6: Creating Bluetooth Function Buttons
I wanted the buttons to be made out of wood as well, so I cut a dowel slightly longer than the width of the frame, as these will be sanded down flush later on.
Step 7: Gluing the Frame Together
Once all the panels were ready, I lined them up and put some masking tape to hold them all together.
Then I applied a generous amount of wood glue in between all the 45 degree angled cuts and used masking tape again to hold the frame together while the glue dried.
I let the glue dry for a minimum of 24 hours.
Side note: I ended up attaching the power supply to the frame before gluing the walls together, as there was no way of attaching the power supply once the pieces were to be glued. A design flaw... haha
Step 8: Creating the Front and the Back Panel
I cut another piece of wood to fit inside the rabbet cavity that was created in Step 3.
Then I drilled a hole and used a chamfer bit on the router to create a neat opening for my drivers and my tweeters.
The back panel was the similar idea, without the extra holes.
Step 9: Filling and Sanding
The chamfer cut had left a small chip on my front panel, so I collected some saw dust and made a putty with some wood glue.
I filled in the hole and once everything was dry, I sanded everything down with a sander with a fine grit paper.
Picture 3 shows my bluetooth buttons, sanded down flush with the frame.
Step 10: Staining and Finishing the Wood
This wass personally my favorite step.
I stained the frame and the back panel with a dark brown stain and for the front panel, I just used teak oil to give it a warm color.
Step 11: Wiring Up!
After all the woodwork was done, I brought everything inside, where I worked on the electronics.
I bypassed all the push buttons on my bluetooth module and wired up my own set of push buttons with extra wires. (See pictures 3 and 4)
I added a microphone to my board so that I can also take phone calls. (See picture 5)
and then I de-soldered and added some wires to all the potentiometers on the preamp so that I can route them to the holes I had created on the frame. (See pictures 6 to 8)
Step 12: Fitting All the Electronics
Once everything was wired up, I ensured that all the parts fit properly.
I attached the front panel speakers and tweeters and then I was ready for a smoke test.
Step 13: Smoke Test
After connected everything, I plugged it in for a test.....
Phew.. nothing started bursting into flames and all the buttons and the knobs seemed to work perfectly!
Step 14: Admiring and Feeling a Sense of Accomplishment
After ensuring everything worked perfectly,
the final step was to close it all up and stand there admiring my work... No, seriously.
I designed my soundbar so that it can either sit on my bed, or have it standing and be used as a tower speaker with all the controls placed at the top.
The next step was optional, but I created some legs for the soundbar which went quite well with the design. (See picture 8 to 10)
Well, this is all I had for this Instructables. Thanks for reading my Instructable and I hope you enjoyed it!