Black Walnut 2.1 Speakers

This project is about manufacturing a premium 2.1 speakers system which incorporates both basic enclosure design and aesthetics. I wanted to create a set of speakers that can both be used in the living room for a TV and a PC setup. The main theme of the design is a rustic and clean look. I liked the combination of walnut wood and black MDF, as it provided both good aesthetics and acoustics. This is why those materials have been chosen, hence the name "Black Walnut". One major specification is the system must be able to provide loud and undistorted sound, to achieve this, I used more premium speakers (although mine were a slight overkill). The 2.1 setup includes 2 satellite speakers each with a dedicated mid and tweeter, and a separate subwoofer module. The system will eventually include an amplifier as well, but that will be reserved for another instructables for another day.

Important Disclaimers:

This whole project has been done in a workshop of 3m^2. The reason is I live in a flat so space is not abundant. But it also means that this project can be manufactured in almost any workshop.

In terms of difficulty, this is certainly not beginner, however, it's not that difficult either. Anyone with the right gear and material should be able to manufacture this. Bare in mind that it is rather time consuming, this project took me 2 weeks using my spare time, but it is possible to manufacture this over a weekend if you have the time.

It is also important to note, I am neither an audio engineer nor a carpenter. I just love making speakers, that all:). This project is not filled with pro tips, but rather just me sharing my limited knowledge of this field.

Please do note that this is not a small project and will require a lot of material and tools. Due to the fact that I don't live in the US nor Europe, my sources for materials render useless to 99% of viewers as they simply don't ship worldwide. However, I'm sure that the same material can be purchased on Amazon, Ebay, Aliexpress etc for a slightly higher price. For this reason, I don't see a point in posting the links, but if you would still like them, just let me know.

Raw Materials:

MDF (I would recommend 300*400*8mm sheets. Prepare 12 sheets and perhaps more in case of mess-ups)

Real walnut veneer

1.5mm plywood (at least 665*340mm)

Small square wood pieces for Knock-down fittings

M3 M4 and M5 screws

Rubber legs x12

80mm Speaker vent x1

Acoustic foam

Acoustic tape

Electronics:

Tweeters x2 (1inch, 4Ω, 35w) (Model: MA260)

Mid x2 (4inch, 8Ω, 30w) (Model: CM402)

Woofer x1 (8inch, 8Ω, 250w) (Model: CM838D)

Crossover - (Model: Weah D-226)

Audio Connectors x3

Audio Wire

Tools:

Circular saw (Honestly most cutting tools can get the job done, though I would recommend electric saws if possible)

Router (with fillet, chamfer, straight and straight with bearing routing bits)

Drill (with a variety of drill bits)

Soldering Iron (with the regular soldering kit)

Wire Strippers

Crimps* and a Crimping Iron*

3D printer*

Other:

Wood Glue

Quick dry PVA Glue

Black Spray Paint

Clamps

Abrasive paper

* for optional equipment

Before starting a project, I prefer to first create a digital 1:1 model of the product. This is a great way to be able to reference parameters later on when cutting and assembling. Fusion 360 has been used for this project, which I understand is not available to everyone. But currently, Fusion, Sketchup and STL files are attached. Each model has a template in the file too. The templates will be 3D printed and used to cut out the MDF accurately.

Although this is optional, my method of construction revolves around using a template to cut the MDF out accurately. Since I don't have a CNC mill, I had to 3D print it. Please bare in mind that the templates do require a large print bed, this a minimum of 300*300mm^2 print area. Please find the STL files above ending in "template".

Because of the weight of subwoofer, I decided to give it a double thickness panel for the strength. This means that a total of 7 panels of x*x will be required. I first roughly cut out the size using a circular saw. Then I stuck 2 of the panels together and clamped the template to it. Using a router and a straight-bearing bit, I routed the side of the panel so that it is flush with the template. Since this is the front panel, the center circle is also cut out with a straight and a straight-bearing bit. Then the corners are routed with a chamfer and fillet bit.

The other 4 side panels will only be routed on the side with the template, but will also be chamfered on 2 opposite sides for the miter joint.

The final panel is the back panel which will have to be cut freehand. Since its at the back, it doesn't have to be the best cut.

The four side panels are then glued together along the mitered sides. Ensure when doing so that each corner is a right angle.

Once the partial enclosure has dried, I stuck knock down fittings at the back so the back panel can screw onto something.

The back panel will include a 80mm vent and an audio terminal. To cut the hole for the vent, I found the center of the panel and then freehand routed an 80mm hole. The rectangular cutout for the terminal is cutout with a drill and file.

It is a good point here to put the panel in its mounting position and spray paint the panel black.

The vent is then slotted in and the terminal screwed in. I also drilled pilot and clearance holes into corners of the panel and the knock down fittings for counter sunk screws to later be crewed in.

Now the front panel is glued onto the front side of the enclosure.

After drying, I spray painted the panel black

To achieve the aesthetics of walnut wood, I used real walnut veneer. Each veneer has been cut slightly bigger than the required size of 270*270mm^2 so there is room for error. I coated each side with a thin layer of quick-dry PVA glue before sticking the veneer. Contact adhesive is also an option when sticking veneers, but since it was my first time, I wasn't confident with it yet.

After it dried, I briefly sanded off the extra bits so that everything was flush.

In order to boost the sound quality of the ensure, the basic compression chamber had to be "acoustic foam"ed in order to provide damping. The foam is just cut out roughly to size and stuck in with PVA glue.

For the aesthetics and acoustic reasons, I screwed on some small rubber legs to each corner of the bottom of the enclosure.

Now that everything is done, I soldered some high power audio wires to the woofer and screwed the driver into place. The other end of the wire is then soldered onto the terminal on the back panel. You could also crimp the wires instead so its a non-permanent joint between the speaker and the wire, but its not necessary.

The back panel is then closed and the counter sunk screws are screwed in.

The subwoofer is now complete and should be tested to ensure functionality.

Part 2 will now begin with the manufacture of both satellite monitors.

Due the curve of the speaker, the plan is to create the main structure first and laminate a layer of plywood over it.

The cutting of MDF will include 4 main panels, 2 of which have the holes cut out too. And 8 pieces for the internals. Bare in mind, this is all the cutting required for both speakers.

Once again, the 4 main panels are cut roughly to size using a circular saw, then routed to the precise size. The other 8 pieces are cut freehand as they are mounted in the inside of the speaker and don't need to be as accurate.

These monitors will have far more electronics than the subwoofer. The photo above shows everything besides wires that will go into both of the speakers.

It is a good point now to spray paint all the outside panels black before further manufacturing.

The terminal will no have a cutout at the bottom of both of the back panels (the curved panel without holes).

Wires can then be soldered to the terminal and both terminals screwed into place.

Solder the terminal wires to the input of the cross over and solder wires to the output as well. Then you can screw the crossover into place.

Then I took both of the cross section panels an glued them to the bottom panel. The top panel then had the speakers mounted and screwed onto it. Before gluing the top panel to the vertical cross section panels, I would recommend soldering the wires from the crossover to them. Then I glued the top panel on.

It is good practice now to test the functionality of the speaker incase of a faulty solder joint, otherwise you won't be able to fix it once the enclosure is laminated.

Once the functionality is ensured, then I glued in the last 2 panels to complete the basic compression chamber for the mid. The vertical piece is to isolate the crossover from the compression chamber. The horizontal panel to to partially separate the driver from the vent. If you want, you could cove the compression chamber with acoustic foam, but since this is not a bass heavy driver, I didn't see a massive point for the effort.

The lamination requires only one piece of 1.5mm plywood for each speaker. This is cut slightly larger than the curved surface length and width. Glue is applied and the plywood is bent around the shape and clamped down. It is important to eliminate any air gaps otherwise it will look unprofessional.

Once this has dried, I applied a very thin layer of quick dry PVA glue to the surface of the laminate plywood. Then bent the walnut veneer over just like the laminated plywood. The extra bits of plywood and veneer can then be routed off with a straight bearing router bit.

The whole system is now done, connect this to an amplifier and it will work like a charm.

I understand that this intructables is perhaps not the most detailed one, so if there are any questions regarding any aspect of this project, please do comment or contact me :)