Powered Rustic Speaker Bar With Bluetooth

I wanted to improve the sound quality of the TV in our living room and my wife wanted a Bluetooth speaker that was powerful enough to be heard in the kitchen so she could listen to music while cooking. After testing various speaker bars, I was unsatisfied with both the looks and the HiFi capability of what was available at the store. I wanted something that matched the decor in our house, not a nondescript black bar with a separate sub woofer. I decided I could design and build a powered speaker bar with an integrated subwoofer that would satisfy our needs for less money than what is currently offered at the store.

One of the main design goals of this project was to match our current living room decor. I chose the HiVi B3S because I thought the copper would match the rustic look I was going for and the 3" size of the driver meant I would be able to keep the speaker bar thin enough to fit under my TV. I wanted the speaker bar to be about as long as my TV and since MDF comes in 4ft x 2ft sheets, I decided to use 4 feet for length. I also wanted to incorporate a sub woofer into my design and chose the RS150 6" Dayton Reference. I found a project on Zaph Audio that used the B3S and decided to modify the design to suit my speaker bar. I modeled the 6" Dayton in WinISD and found it modeled well in ported enclosures. I wanted to keep the response as flat as possible with a low frequency cut off around 50 Hz. This was achieved in a .45 cu ft enclosure with a 3" long, 1.5" diameter round port tube. I began designing the speaker bar around these numbers and drew the resulting enclosure in SketchUp.

The small size of the HiVi B3S limits its low frequency response. A crossover is used to limit the frequencies that go to the small driver and prevent any possible distortion that would result from low frequencies. The crossover was designed by Zaph Audio to prevent these frequencies from reaching the B3S, anything below 200 Hz will be handled by the Dayton Reference woofer.

Wood:

To keep costs down I chose a combination of Poplar and MDF which you can find at any major hardware retailer. Any wood can be used if you do not have this available in your area. I have included a cut list and diagram, some hardware stores will make the cuts for you if you do not have a circular saw or table saw. I do not have a planer or a jointer so I got S4S (surfaced 4 sides) Poplar from Lowes. Prices reflect current costs in my area, the total cost of the project may vary depending on where you live.

• 2 x S4S Poplar 1/2" x 6" x 48" Lowes ------------------------------------------------- $9.50 Ea.
• 1 x S4S Poplar 1" x 8" x 48" Lowes --------------------------------------------------- $15.00 Ea.
• 1 x MDF 1/2" x 24" x 48" Home Depot ------------------------------------------------ $12.00 Ea.

Wood Total Cost: $46.00

Electronics:

• 2 x HiVi B3S Parts Express -------------------------------------------------------------- $10.00 Ea.
• 1 x RS150 Dayton 6" Reference Woofer Parts Express -------------------------- $36.00 Ea.
• 2 x 12V Power Supply Amazon --------------------------------------------------------- $10.50 Ea.
• 1 x Sure Electronics Bluetooth Receiver Board Parts Express ----------------- $25.00 Ea.
• 1 x 2.1 channel Class D Amplifier board Parts Express -------------------------- $10.25 Ea.
• 1 x Headphone Splitter Walmart ---------------------------------------------------------- $4.00 Ea.
• 2 x 8 Ohm Ceramic Resistor Parts Express ------------------------------------------- $1.40 Ea.
• 2 x 30 Ohm Ceramic Resistor Parts Express ----------------------------------------- $1.40 Ea.
• 2 x 4.3 µF Capacitor Parts Express ----------------------------------------------------- $3.00 Ea.
• 2 x .8 mH Inductor Parts Express -------------------------------------------------------- $4.00 Ea.
• 2 x .1 mH Inductor Parts Express -------------------------------------------------------- $7.00 Ea.
• 1 x 16 Awg Speaker Wire Parts Express ----------------------------------------------- $7.00 Ea.
• 1 x Auxillary Cable Amazon ---------------------------------------------------------------- $5.00 Ea.
• 1 x Assorted Heatshrink Parts Express ------------------------------------------------- $3.75 Ea.

Electronics Total Cost: $165.60

Miscellaneous Materials:

You will need wood glue, liquid nails for sealing the joints and a small amount of fiber fill such as Poly-Fil. I had originally intended to paint the speaker bar with chalk paint but decided to stain it in the end to better match our living room furniture.

• 1 x Poly-Fil Walmart ------------------------------------------------------------------------ $3.50 Ea.
• 1 x Wood Glue Lowes --------------------------------------------------------------------- $2.00 Ea.
• 1 x Liquid Nails Lowes --------------------------------------------------------------------- $3.50 Ea.
• 1 x Port Tube Parts Express -------------------------------------------------------------- $1.65 Ea.
• 1 x 3/8" Screws Lowes --------------------------------------------------------------------- $7.00 Ea.
• 1 x 3" Paintbrush Lowes ------------------------------------------------------------------- $1.00 Ea.
• 1 x Wood Stain Lowes --------------------------------------------------------------------- $4.75 Ea.
• 1 x Tack Cloth Lowes ----------------------------------------------------------------------- $5.00 Ea.
• 1 x Plastic Drop Sheet Lowes ------------------------------------------------------------ $3.00 Ea.
• 1 x Sand Paper Multipack Lowes -------------------------------------------------------- $4.00 Ea.
• 1 x Blue Masking Tape Lowes ------------------------------------------------------------ $6.00 Ea.

Miscellaneous Total Cost: $41.40

Total Project Cost: $253.00

I used the following tools to build the speaker bar. They are not all required, but they make the job a lot easier.

• Pencil
• Soldering Iron
• Table saw or Circular Saw
• Miter Saw
• Bar Clamps
• Corner Clamps
• Drill
• 1/4" Drill Bit
• 3/8" Drill Bit
• Router with Circle Cutting Jig or Hole Saw set
• 1/8" Straight Router Bit
• 3/8" Rabbeting Bit
• Hot Glue Gun
• Random Orbit Sander
• Tape Measure
• Combination Square

Most hardware stores will make these cuts for you if you do not have a circular saw, table saw, or miter saw. If you have a saw available, make the cuts as indicated by the cut list and diagram. Be sure to wear the proper safety glasses or goggles while building this speaker. MDF can be hazardous to your lungs so wearing a dust mask is recommended. To prevent tear out while making the cuts, use blue masking tape on the bottom side of where you are going to make the cut,this will reduce the amount of finish sanding you have to do.

Make a mark 4.5" from the left and right side of the front baffle, measure 2 5/8" from the top and make another a mark. These intersection of these marks will be the center of each speaker cut out as shown in the picture. Using a router with a 1/8" straight bit and a circle jig, cut a 2.75" diameter hole at each mark.

Make a mark in the center of the top baffle by measuring 24" from the left side and 3.5" from the top. Cut a 4.75" diameter hole at the center of the top baffle. Using a 3/8" rabbeting bit, set your router for a depth of 3/8" and rabbet around the hole in the top baffle. This will countersink the Dayton speaker into the top baffle, I have included a closeup of the top baffle for reference. The HiVi drivers have a square frame making it difficult to countersink them into the front baffle. I mounted them on the inside of baffle so they would not be sticking out of the speaker cabinet.

Using a drill and 2.5" hole saw, drill a hole in the back MDF panel 14" from the left side and centered between the top and bottom edge. Cut the port tube to a length of 3" and glue it into this hole as shown. Near the center of the back panel, drill a 1/4" hole a half inch from the bottom edge. Drill a 3/8" hole four inches from the 1/4" hole, also a half inch from the bottom. A 3rd and final 3/8" hole can be drilled anywhere near the port tube, this will be for the power cable.

Clamps will be your friend in this step...many, many clamps. Add a line of glue to a long edge of the top baffle and clamp it to the back of the front baffle using corner clamps. Add bar clamps along the top baffle to apply even pressure along the glue joint. Use small strips of wood to protect the surface of the front baffle as shown in the picture.

Glue the back and bottom MDF panels together using the same process. The edge of the back panel will be glued to the back of the bottom panel.

Clamp and glue the inside MDF panels 8" from the left and right side of top and front assembly. Be sure to clamp the panel to both the top and front baffle as shown, again using small strips of wood to protect the surface of the wood.

The left and right sides are glued in the same fashion making sure all sides are flush, this required more clamps than was required for the internal panels.

Warm up the hot glue gun and plug the Y splitter power cable into each 12V power supply. These should be hot glued side by side under the port tube as shown. Cut one of the power supply AC cables in half and thread it through the 3/8" hole you made near the port tube. Splice the power cable back together using heatshrink tubing to keep the 3 wires separated and a larger piece of heatshrink around the entire splice. If you are not comfortable with this splice, cut a hole in the back panel using a jig saw to fit around the female end of the Y splitter power cable and glue it in place with hot glue. Put the amplifier's volume potentiometer through the 1/4" hole in the back panel and seal around the hole being sure not to glue the arm of the potentiometer itself so you can still turn it and adjust the volume. Glue the amplifier corners down to the bottom panel so it stays in place. Connect the headphone splitter male end to the amplifier.Secure and seal of the female ends into the 3/8" hole you drilled near the amplifier, this will be an auxiliary input for the speaker bar. Connect the auxiliary cable to the remaining female input and connect it to the Bluetooth receiver. Glue the corners of the receiver to the bottom panel near the amplifier as shown. Remember that this part of the speaker is used as an enclosure for the 6" Dayton woofer so all the holes need to be completely sealed with hot glue to prevent air leaking out.

The .1 mH inductor will need to have 5 windings cut off of it to make it a .08 mH inductor. Start by making a mark down the side of the inductor where the outside lead starts. Unwind the outside lead, counting each time you reach this mark till you have unwound it 5 times. Cut off the wire that you have unwound leaving approximately 2" of wire lead after the mark you made. Sand the enamel coating off this newly created lead so you are able to make a strong electrical connection. Solder each crossover together as shown in the circuit diagram and picture. The output of each crossover is the .08 mH inductor and will need a single short speaker wire soldered to it. The input is the .8 mH inductor and will need a speaker wire long enough to reach the amplifier soldered to it. Using hot glue, secure each crossover assembly inside the left and right chambers that are created by the internal MDF panels as shown. It is important to glue them in the exact orientation as shown in the picture. Each inductor should be 90 degrees from the other and one should stand on its side while the other lays flat. This will prevent the inductors from interfering with each other and producing unwanted effects. Connect each long wire from the input of the crossovers to their respective +L/+R channels on the amplifier. Connect another long wire from the -L/-R channel on the amplifier to each respective chamber as shown, these will be connected to each speaker. A short speaker wire pair can be attached to the subwoofer output of the amplifier for the Dayton woofer.

Normally you would sand and stain after the final assembly but because the HiVi drivers are being mounted on the inside of the speaker and the MDF doesn't need to be stained, I decided to stain prior to assembly. The S4S poplar should have a decent finish on it and doesn't require a lot of sanding. If there are some bumps and dings acquired while assembling, those can be sanded out with 80 grit sand paper on a random orbit sander. After removing any blemishes, the entire project should be sanded with 120 grit and followed with 220 grit finish sanding. This should give a smooth surface with enough bite to take on an even stain.

Layout the drop plastic on the ground and place the poplar assembly on top. Using the tack cloth, wipe down all surfaces of the project to remove any dust and debris. Follow the stain manufacturers instructions to apply the finish coat to the project. I used the foam brush and coated all the outside surfaces with stain and let it sit for 10 minutes before wiping it off with paper towels. It is best practice to try the stain on a scrap piece of poplar to make sure you like the finish. You can use painters tape to tape of sections of the scrap and try different soaking times to see which you like best. My stain did not require multiple coats or sanding afterwards.

Before gluing the front half to the back half, run a bead of Liquid Nails along the inside corners of the edges where the halves will meet. This will prevent air from leaking at the joints between the two halves. Also seal the corners of the internal MDF panels so each side chamber is sealed from the middle chamber.

Place the HiVi 3" drivers onto back side of the front baffle centered in each speaker hole. Attach the each drvier to the front baffle using four 3/8" screws. Place the Dayton 6" reference inside recessed speaker hole on the top baffle and secure it with six 3/8" screws.

Place the front assembly near the back assembly and solder all the speaker wires to their respective speakers. Divide the Poly-Fil between the left, right and middle chambers with the middle getting about 60% leaving 20% for each side.

Run a bead of glue around all the edges of the MDF back assembly and mate it with the front assembly, the speaker wires may cause difficulties so small notch can be cut on each internal MDF baffle to allow the speaker wires to pass from the side chambers to the middle chamber. Make sure each notch is sealed tight. Clamp the two assembly halves together and let dry overnight.

The speaker is assembled and ready for music. Plug the power cable in and connect your audio source to the speaker either through the auxiliary input or by connecting to the Sure Hifi Bluetooth receiver. Adjust the volume knob on the back to your comfortable listening level and enjoy.

In the end I think the speaker sounds great and has plenty of low end. It looks great under my TV in the living room and gets loud enough to hear throughout the house. Let me know if you build one yourself or have any questions for me.

The electronics are all accessible if you remove the 6" woofer on the top. That should give you enough room to fix any problems that may arise.