In this Instructable I will try my best to explain to you how I built my solid Oak Bluetooth speaker.This is my first Instructable, and I didn't document the process as mush as I would have liked to, so please excuse me if this Instructable isn't that instructive! However, I am more than happy to answer any questions.
A big shout-out to Joseph Norster from The Projects in Melbourne, whose resources, expertise and guidance made this project possible. yet this speaker isn't even comparable to way more interesting stuff that they do there, make sure you check it out if you happen to be around.
I would recommend this project to keen DIYers eager to build some speakers. A little bit of woodworking skills and soldering experience is required.
In regards to the complexity of this build, I would say that this is easier than it looks. it is important to have a clear design sorted out before you start building.
That's enough conversation and confession, lets build a speaker!
Step 1: Description and Key Terms
What is a Bluetooth speaker?
A Bluetooth speaker plays audio wireless through your mobile device. So you can place your speaker the living room and select the songs you want from the kitchen etc, through your phone. The one I built is quite similar to the off the shelf products available like the Audio engine B2 wireless speaker, which costs around $450. You could pull off this DIY speaker for under $50-$60 depending on what speakers and timber you use, and shipping costs. This costed me a lot more because of the amount trial and error that went in to getting it right, but my experience means you get to skip that part! I have to say, genuinely, this speaker sounds great. I prefer the sound of this speaker over the performance of much more expensive off the shelf products.
How does a Bluetooth speaker work?
Regular sound systems work by taking a small sound signal, which could be through the headphone jack of a phone, a CD player, a record payer etc, and enlarging the signal through an amplifier, and playing it through a speaker. In a Bluetooth system, this initial signal is transmitted wirelessly by your phone, and received by a Bluetooth receiver which passes the signal to the amplifier which amplifies the signal. This amplified signal is then played through the speakers. Therefore, a Bluetooth speaker will compose of a Bluetooth Module, an Amplifier, and speaker drivers.
Bluetooth - A wireless data transfer technology
Bluetooth receiver board - A circuit board that uses Bluetooth technology to receive signals from your phone. I will call this Bluetooth module, Bluetooth Receiver, or Bluetooth board.
Speaker - An audio reproduction device
Speaker driver - The component of the speaker that actually moves and makes sound. Speaker drivers are just simply called speakers most of the time.
Amplifier - A device that processes a weaker electrical signal into a powerful one that can be converted to sound via speakers.
Amplifier Board - A circuit board of an amplifier, I will call this amplifier module or amplifier board.
Step 2: Designing the Speaker
This step is as important as building the speaker itself. A clear design and vision of what you are going to build will lessen the chance of stumbling and making errors when you come to building. Here I will try and describe the process of designing your own speaker, the rest of the instructable will be specifically about my build.
Here I've posted a few pictures of the plans I drew up on Sketchup, which I highly recommend for beginners.
I've also attached a Sketchup file of the final product so you can play around and get a better idea of the anatomy of the speaker.
I am not very good at Sketchup or any other CAD software so it is probably not very good, but I did my best!
Some things to consider when designing
How much you are willing to spend
whether you are more fussed about the looks, or about how it sounds
What size do you want the speaker to be
How quickly you want to get it done
1. Decide what main material you want to use.
Wood is recommended, I used oak for its beautiful grain, you can experiment with anything you have, and if you are brave, you could use wood from old pallets and stuff. For the best option in terms of audio quality, MDF or chipboard is needed for the most neutral sound. If you choose to use MDF but still want that 'woody' look, you can veneer it.
2. Workout the size you want, and determine the exact dimensions of the materials accordingly.
3. Sketch your plans. I used Google Sketchup to help me design, and it was super helpful. It is a free software, and you can become quite proficient in less than a day.
4. Decide the finish you want on your final product, make sure you get this just right, so you can adore your speaker even when it is not playing music.
5. Decide what speaker drivers you want to use. browse www.parts-express.com to get an idea of what speaker drivers you can use, and read the reviews from purchasers to see what speakers you want. I personally recommend Dayton Speaker drivers. I also recommend the loudspeaker kit and Wagner Electronics as good websites to shop for speaker drivers.
6. Select Suitable Amplifier and Bluetooth module
I recommend that you use an amplifier board as I, and most other people use when building these kinds of speakers, they are circuit boards which will power your speaker, and cost a fraction of what a fully assembled amplifier will cost. try and find a board that will cater to your speaker driver's power requirements. Remember that under powering your speakers is better than overpowering them. For example, the speakers I used were 30 watts Max each, and I used a 20 stereo watt amplifier ( which provides 20 watts for each speaker) . I used very efficient drivers, and therefore the Bluetooth speaker produces plenty of volume.
Try to get a good Bluetooth receiver module, the latest versions of Bluetooth are pretty good, crappy ones will compromise sound quality. I've seen some amplifier boards that have inbuilt Bluetooth, that would be a worthwhile investment, and would make this build less complicated.
I live in Australia, therefore my choices are limited, and I have to pay a lot more than what Americans have to pay. I spent more than twice the actual cost of the parts experimenting with different speakers and amplifier combinations, and finally settled on what I have. Therefore , I naturally recommend the electronics that I have used in this build.
7. Select parts for making the speaker portable, If you want it to be portable. I chose not to make mine portable as it is too heavy to carry anywhere. Do some research on this topic before you start designing. Portability revolves around the usage of rechargeable batteries instead of mains power.
Here is the Sketchup file that would let you navigate around the 3D rendering of the finished product, download Sketchup to view it.
Step 3: Prep Up
Tools that you will need
Mitre Saw - you can try other methods to cut your materials to size
Electric drill with various drill bits
Spade bit - To cut a hole for the volume knob.
Hole saw attachment for your drill ( to cut holes for the speaker)
Tools that you will need
Soldering Iron - To wire everything up
Optional - sander
Materials that you will need
Timber ( Oak,in my case)
Varnish or any other finish you want to use
Sand Paper 240 grit, and 600 grit
regular heavy duty hook up wire
Optional - Heat shrink tubing to insulate everything
Parts that you will need
2 Speaker Drivers
Cheaper for Americans - http://www.parts-express.com/dayton-audio-dta-2-cl...
Bluetooth receiver Module
Panel mount DC input socket
Panel Mount 3.5 MM auxiliary socket
Panel Mount 12 V wired led
10 K ohm logarithmic potentiometer
Brass Engraving plate
Step 4: Woodwork
The Basic idea
The speaker box is made of 8 pieces wood.
The top and the bottom - 2 pieces
The sides - 2 pieces
The front and the back - 2 pieces
The internal supports 2 pieces
These pieces are needed to hold the structure together and to fasten the front and the back to the frame of the box.
I cant remember the exact sizes, I will upload them if I find any files.
The top and bottom and the sides have mitered edges for seamless joints in the final product, if you are using MDF and are planning to veneer it, you can use butt joints because the joints will not be seen.
The mitres are cut with a mitre saw set to 45 degrees, you can try butt joints instead if you are not confident with cutting mitres, or don't have access to a mitre saw.
Cut the wood to size
Cut holes for the speakers and the volume knob
cut another space for the instrument plate at the back
Glue the top and bottom and sides together using clamps
Once the frame is glued, glue the internal supports
Attach the front with glue, but not the back. The back will be attached last.
Fill any pores, cracks and Knot holes with wood filler
sand the hell out of every part that will be seen, first with 240 grit sandpaper, and then 600 grit sandpaper, always go with the grain.
stain a piece of scrap wood to get an idea of the way to achieve the perfect colour
Stain outside of the box which will be seen when the speaker is complete
finish the speaker with a clear finish, make sure you are patient as this is the final look of your speaker, I used Tung oil for a natural satin finish. It did end up with a nice smooth satin finish. I was going to varnish the box, but then I got high.
Step 5: Wiring
This is the step where the actual sound comes into play (pun intended). If you keep this simple and organised, this step will be easy. This is my favourite step, as it involves soldering. Involves soldering.soldering.
I rest my case.
The wiring will be split into two steps :
Power wiring - how the circuits are wired to the power input.
Audio wiring - how the circuits are wired for audio.
The wiring diagrams that I've included will be helpful, in addition, read these instructions to wire up the speaker.
Before we delve into the realm of wires and solder, remember that the key to success here is to keep testing the whole system as you go along, play your favourite songs, check if they sound perfect. After all, you don't to finish the speaker and find out only that only one speaker works!
Fixing the speakers
First, you have to fix the speakers to the box. Wire speaker wire to the positive and negative terminals of the speakers and solder them in place. I recommend that you use Heat-shrink tubing to insulate the terminals, but this is optional. Make a note of which wire is connected to the negative terminal of the speaker and which is connected to the positive terminal of the speaker.
Place the speakers over holes in the box, and align the speakers the way you would like them to be in the end product. Mark where the holes are and drill holes. Replace the speakers and screw them down with screws. The wires should be in the inside of the box now.
Wiring the power
Use the Wiring diagram to help you. Simply, the positive from the power input socket runs to the positive of the led, the positive of the Amplifier and the positive of the Bluetooth receiver board. likewise, the negative from the power socket runs to the negative of the led, the negative of the amplifier, and the negative of the Bluetooth receiver module. Use heavy duty hook-up wire for this job.
Wiring the Audio
Once again, the wiring diagram will help you in this step. There are three wires in a stereo set up like this, the left channel's positive, the right channel's positive, and the common ground. I included an auxiliary input in my speaker, and I recommend that you do too, because you can simply plug in other sources via this input or just simply connect to your phone via an aux cable when Bluetooth is not available. I actually use this input more than Bluetooth. You can omit the auxiliary input if you want you speaker to be Bluetooth only.
So the Auxiliary input is in the form of a 3.5 mm auxiliary socket (basically the headphone socket in your phone). The three wires (left, right, and ground) are run from this to the Bluetooth module, which also accepts an auxiliary input. The Bluetooth Module either uses the auxiliary signal from this input or processes the Bluetooth audio signal from your phone, and sends it to the amplifier. Therefore, you should run the three wires (left, right, and ground), from the output of the Bluetooth board to the auxiliary input of the amplifier board. As shown in the diagram. The amplifier has four outputs, positive and negative for the right speaker, and positive and negative for the left speaker. wire the positive left output of the amplifier to the positive terminal of the left speaker, and the negative left output of the amplifier to the negative terminal of the left speaker. Repeat for the right speaker.
Wiring the Volume Control
The shaft of the volume control given with the amplifier was not long enough for my box, therefore I bought a potentiometer (variable resistor), cut the wires going to the given potentiometer, and soldered it to my one. Then I mounted it on a metal bracket which could be fixed inside of the wooden box. I drilled a hole for the potentiometer shaft, inside the hole for the volume knob (see picture), and glued the potentiometer into place.
Then I connected the wires going from the potentiometer to the amplifier board.
Step 6: Final Touches
The Innards of the speaker
Fix all the circuitry inside the box, use short screws as most circuit boards have screw holes. Roll up an loose wire, and tie into neat bundles using Zip ties, Keeping the inside as neat as possible will make possible trouble shooting less of a nightmare.
The Instrument Plate
I got this brass plate from my local "key-cutter/engraver", Mister Mint. He engraved some labels and names on to it. I drilled the holes my self. I Drilled holes for the led, the power socket and the auxiliary input, and two screws prior to it being engraved. Be careful when you drill it, because the plate can be easily ruined. As shown, I stuck a template to drill the holes in the correct places.
Fix the 12v wired led, and the power socket and auxiliary input to the plate using the given bolts and washers. Fix the instrument plate to the back panel using screws.
The volume Knob
Fix the volume knob to the shaft sticking out of the front of the speaker. Play some music and see if the volume knob turns smoothly, and works properly.
Finishing it up
This is the final step of this journey, screwing the back panel to the speaker box. I used the same black screws, and drilled holes first, then screwed the panel in.
And its Done. Now play your favourite music, and gaze upon this artwork that you have created!
I am quite please with the end product, It is certainly more beautiful than shown in the photos, and I could spend the whole day running my hand over it's smooth surface. I wanted to go for that "Timber Look", and I believe I nailed it.
The sound is great too. The highs are rich and sharp, and truly makes the room feel alive. The vocals are crisp and clear, and just excellent. Its as clear as a very expensive pair of headphones. The bass, though it does not shake the room, is present, and it is accurate and enjoyable as well. Acoustic guitars are just unreal on this speaker.
My favourite thing about this project is that I had an exact idea of what I wanted it to look like even before I started gathering materials and parts, I planned it thoroughly. And it ended up looking exactly like that. I am truly proud of that fact. I built this for someone else, and the thought that someone is using a project, a product, that I built is just the greatest reward that I could ever have.
Thanks for reading, please ask me any questions that you have about this build. Also make sure you post pictures if you build something similar.