Audiophile Bookshelf Speakers From Scratch

I've been using some satellite speakers for my home theater setup for a good long while. Recently, I've been less than impressed by the sound they provide, especially while trying to recreate full-band performance from the turntable (I don't have quite enough space for towers and a sub atm).

There are multiple options on the market for making speakers from matched pairs of drivers. Some even include the pre-cut MDF to build the cabinets. These tend to be far into the form-following-function realm; with a great deal of the price of quality speakers going to the name, you can put the bulk of your budget towards the drivers where it counts.

Wanting to up the craftsmanship a few notches, I decided to flare the sides of my boxes and add figured walnut fronts. Let's see how this goes.

Supplies

The primary supplies for the speakers are the drivers. I used a high-quality set from MadiSound:

https://www.madisoundspeakerstore.com/mtm-speaker-...

The kit included all of the wire, connectors and supplies to finish the build although I would recommend having a few spares in case mistakes are made along the way.

The cabinets used 3/4" MDF found at your favorite big box store. The pieces I bought were 16" x 4', which was a perfect size for the height of the cabinet, although I didn't know it at the time.

The fronts were made from figured walnut shorts found at Gobi Walnut:

https://gobywalnut.com/collections/shorts

I added poly speaker fill to improve resonance, about 1 lb. per pair was enough:

https://www.crutchfield.com/p_027808/Polyester-Fib...

Paint is standard brush-on Rustoleum gloss black

To measure the speakers' performance, I used a studio microphone and Room EQ Wizard:
https://www.roomeqwizard.com/

Tools required: A few are required, mainly the table saw, band or jig saw, a belt sander and a router.

I also used a thickness sander, drill press and a biscuit jointer to increase the strength of the sides.

Step 1: Planning the Design

As with most of my projects, I started in Publisher by laying out the sides of the cabinets. The front panel stays the same size as the manufacturer's recommendation for a rectangular box. Each panel changes its angle by 15 degrees, allowing me to set the table saw at 7.5 degrees later on and cutting each piece in one shot.

Time for some math! Once I got the sides to widths that could be easily cut (3", 2", 4 3/8", 3 1/8"), I added some boxes to the Publisher model to get the size of each segment which is now a trapezoid . With that, I created an excel spreadsheet to calculate the area of each one. A summation gives the area of the base in square inches, about 75.4" sq.

The manufacturer gives an ideal volume of 0.7 cubic feet. At the rate of 1728 (12^3) cubic inches per cubic foot, this comes out to an ideal volume of about 1209 cubic inches. If we divide this by the area calculated above, we get an ideal height of 16.036".

This is what we call synergy, as the MDF panels I was able to find came in 16 inch widths.

Step 2: Building the Cabinets: Part 1

With the cabinets' shape determined, it's now time to begin construction. Since each cabinet has two identical sides, it is easy to cut each stave en masse to reduce the amount of machine setup and reduce the chance of things not fitting.

As stated above, I used Publisher to snap the angles at 15 degrees, so I set my tablesaw at 7.5 for each pass which would give me the correct pitch. Four total cabinets require eight identical sides.

The back of the cabinet is attached with a higher miter of 37.5 degrees.

Once all of these pieces are cut, I added biscuit slots to aid with alignment and add strength, then began gluing each piece. I started with pairs and built them up. When I added the backs, I also included small spacers on the top and bottom to ensure a uniform size.

After the glue dried, I used a handheld belt sander to round over the joints and leave a single curve from the front of the cabinet to the back.

To create the tops and bottoms, I traced each cabinet onto the MDF and cut a matching piece which I then glued in place. A flush-trim router bit got the size correct and a 1/2" roundover finished the look.

At this point I also decided to add bases, as I didn't want the cabinets sitting flat on my table. I cut one more set of matching bottoms and traced a second version which was 1" smaller all around to create the standoff.

Step 3: Building the Cabinets: Part 2

I routed the bases with a 3/8" roundover bit, shaped the standoffs and glued them up by themselves.

I also added tabs to the fronts to increase the surface area that would eventually contact the fronts. This would improve the cabinet's rigidity and reduce the risk of air leaks.

Step 4: Paint!

We've made it to the step that cannot be rushed! Speakers benefit greatly from fine veneer or highly polished paint. While I didn't quite get to the piano finish, I got close enough for the abuse these will suffer.

Start with a high-build primer and try to fill all of the voids in the MDF and sand it back to have a smooth base to start from.

I used a small roller to add ~5 coats to the entire project, waiting a full day between coats to allow each one to cure. Before the final coat I screwed the bases down so I could get a seamless transition between the risers and the cabinet bottoms.

Once the painting was complete, I used the drill press and a fly cutter to bore the hole for the rear port. I measured a bit too close and needed to heat each port with a hair dryer to get it soft enough to install. Rather than try to add any sanding or buffing, I finished each cabinet off with car polish.

Step 5: Front Panels

The fronts can be as complicated or simple as you desire.

In order to increase rigidity, improve the look and use bookmatched figured panels, I resawed my figured walnut down and glued it up to a backing board of standard walnut with the grains reversed. This will minimize any warping over time. To standardize the thickness, I ran these through the drum sander.

To hide the seam on the sides, I added some of the staves I removed earlier at a 15 degree pitch to match the sides of the cabinet. I did the same on the top and bottom.

At this point I noticed there was a difference in the thickness of each panel. Rather than just live with it, I mixed up some epoxy resin and filled the backs with enough to even out the differences.

I liked the idea of having the cabinet fronts remain square; this was also required since the edges were mitered in place. However, the cabinets were rounded over at the front so if nothing else was done, these wouldn't match up. To solve this problem, I used a handheld sander to round over each corner at the back but have it reduce to a sharp point at the front.

After some furious sanding and polishing, I cut the holes for the speaker drivers based on the manufacturer's recommendations, pre-fit the screws and added plenty of wipe-on polyurethane to fill the grain.

*While the fronts were in work, I also added the speaker crossovers and foam fill inside of the cabinets. More on that later.

Once complete, I attached each front with a thick layer of polyurethane glue, let them dry and buffed the fronts with Renaissance Wax.

Step 6: Electronics and Assembly

My speakers came with assembled crossovers but they required all of the wires and connectors to be cut and installed.

Drill the backs of each cabinet for the + and - connectors and install them with a wrench or ratchet.

Cut each wire to length and crimp the correct plugs to each end. With the wires in place, I mounted the crossovers to the inside walls of each cabinet, marking each wire for the correct driver along the way.

Once the fronts were glued in place and fully cured, I could finally install the drivers and test out the sound.

Step 7: Rock Out!

And that's it! With some careful planning and craftsmanship, you can build a sound system that rivals those costing 5-10x the price and maintain the pride of doing it yourself!

If you really want to compare your results with commercial speakers, you can use a spectrum analyzer to see how they measure up. I checked all of mine against a set of Klipsch satellites and the matching center channel. You can see from the chart that all of the speakers have a similar profile, which speaks to their performance, the green satellite has the sharpest roll-off on the lower end, which is to be expected, and the center channel falls in the middle, which would be accurate given its slightly larger cabinet. More importantly, all of the bookshelves are nearly identical so the construction and assembly tolerances remained fairly tight.