Introduction: Maple OS Powered Speakers
Portable bluetooth speakers are convenient but they can't replace a nice set of bookshelf speakers. I was considering a prebuilt set but enjoy DIY so I did some research on different kits. The kit I settled on were the Overnight Sensations because of the excellent reviews and affordability. The finished kit builds a set of passive speakers which means they need an amplifier to work. I wanted to make them powered or attempt to add an amplifier board within the speakers so that they would run without an external amplifier. I also chose the DIY option because I liked the freedom of customizing the finished product.
There are many builds online, I mainly followed this as a guide during my build.
My goals for this project were:
- Build a DIY kit and learn the fundamentals of speakers
- Add an internal amplifier board to power the speakers
- Maintain connections for an optional external amplifier
- Custom finish for the speakers
Step 1: Cabinet Assembly
The quality of the knockdown cabinet that came with the kit was excellent. Because I was planning on adding the amp board, I needed to drill a few extra holes to accommodate the power jack, RCA jacks, terminal cups, and binding posts. The amplifier board would only be housed in one of the speakers and the back plate of that speaker needed the extra holes. The other speaker would be truly passive and just need a hole for the terminal cup.
The next step was the glue up the cabinet. All of the pieces fit together nicely as they had precut rabbit joints. I glued together all of the sides with the back and clamped it together as the glue dried.
Finally, I drilled a hole in the front face plate for the volume knob. I also had to notch out the bottom right portion to accommodate the volume control PCB.
Step 2: Sanding, Sanding, and More Sanding
After the cabinets were glued together the next step was to sand down all of the edges and joints. Even though the cabinets went together nicely they weren't an exact fit. I also had some squeeze out from the glue. If you are going to build a set of these speakers and finish them with veneer, you need to have a completely flat, smooth surface.
I spent a significant amount of time sanding these cabinets down by hand. A powered rotary sander may have been helpful but the time spend sanding was worth the extra effort!
Step 3: Build the Crossovers
The next step was to build the crossovers. These are all the other components that come with the kit that consists of resistors, inductors, capacitors. The crossover essentially splits the input frequency and outputs the lower frequencies to the woofer and the higher frequencies to the tweeter. I have attached the schematic from the instruction PDF linked above.
I decided to use a thin piece of wood as a "PCB" to assemble my crossovers. The correct connection between the components is the most important part (some also say the inductors should 90 degrees and out of plane from each other too). However, the time spent to make the wooden PCB and the crossovers to look nice is a a testament to my OCD tendencies and a bit overkill (no one will ever see them except for those viewing this instructable). Nevertheless, I positioned the components so that the overall footprint would fit in the bottom of the speaker. I cut out small rectangular pieces of wood using the dimensions of the footprint. I then placed all the components on top and marked where the leads were. I drilled small holes then hot glued and zip tied the components to the wood.
Then I flipped the board over to make all of the connections. I used speaker wire as jumpers and connected them according to the schematic above.
Step 4: Test Your Circuit!
At this point, I couldn't wait to test out my speakers! I wanted to hear how everything sounded and I also wanted to make sure everything was soldered correctly. I connected my my amp to the crossovers to the speakers. I connected my phone to the auxiliary cord. I picked my favorite song and hit play...crossed my fingers...held my breath...and there was sound! Clear sound coming from all of the speakers! Success!
The next step was to finish the cabinet.
Step 5: Finishing the Cabinet
This was the first time I have ever worked with veneer so the whole process was new to me. The veneer I bought came in sheets and I started with the bottom incase I ran into any issues. I layed out the sheet and placed the cabinet on top. I used the bottom face as a guide to cut out the exact dimensions needed.
Some things I learned
- Maintain good pressure on the cabinet so that the veneer doesn't move underneath while cutting
- use a sharp blade to avoid splitting of the veneer.
Once I had both bottoms cut out, I applied wood glue to the back of the veneer making sure to cover every inch in glue. Next, I applied the veneer to the bottom, lined up the edges and placed the cabinet on a flat surface with weights on top. I let the veneer dry and then moved on to the next face.
I worked in pairs, did the same face on each cabinet simultaneously. I also tried to line up the grain as I moved to contiguous faces. Once all of the sides were covered, I was able to cut out the holes in the back for the connection accessories.
After I let all of the veneer dry, I did a light sanding over the veneer and around the edges to merge the different sides together. I decided to add a wipe on natural danish oil. It brings out the grain, shines the wood without compromising the color. I applied 3 coats.
The next step was to paint the front baffles. I decided to use a gray hammered metal spray paint. I thought it would give a nice contrast between the copper woofers and maple veneer. This turned out to be the easiest part of the project. I just spayed a few coats of paint on the front baffles and let them dry.
Step 6: Final Assembly
The first step is to add the hardware on the back of the cabinets and I screwed everything into place including the terminal cups, binding posts, jacks. Attached is a rough schematic of how the connections are made to the amplifier board.
I then used speaker wire to make the connections between the terminal cups and crossovers and speakers.
I used an RCA cord to connect the speaker inputs to the amp board inputs. I just used zip ties to consolidate the excess cord (I didn't think it was worth my time to shorten the cord).
Then I screwed the amp board in place in the top left. It had just enough clearance past the port tube in that position.
Next I hot glued the crossover boards into place. Finally, I screwed in the volume board onto the front panel.
Then I glued the tweeters into the front panel with some wood glue.
Lastly, I glued the front panels onto the cabinets with wood glue and let that dry overnight.
The final step was to screw in the woofers onto the front panel.
Step 7: Enjoy!
You're finished! Now connect your favorite audio device and start listening! I was blown away by the sound of these speakers. They definitely outperform my old small bluetooth speaker. For now they take up a small amount of space and I don't need any external device to play them. But, I like that I have to option to use these as passive speakers if I ever want to connect them to an entertainment center/external amplifier.
A future consideration would be to use an amplifier board that has bluetooth capabilities. With the decreased popularity of the auxiliary/headphone jack it would be nice to connect to these speakers wirelessly.
I hope you enjoyed this build. If you have ever considered building DIY speakers, I highly recommend the overnight sensations. It is easy to build, you can't beat the price, and they sound amazing! Happy making!
Participated in the
Audio Challenge 2020