Follow along as we design a sealed (closed) bookshelf speaker enclosure for a computer setup using Speaker Box Lite. We’ll select the driver, simulate the volume, shape the enclosure, adjust the dimensions, mount the speaker, and prepare the final blueprint for cutting and assembly.
A deep dive into Thiele-Small parameters — the essential language of loudspeaker design. Learn what Fs, Vas, Qts, and other key specifications mean, how they influence sound, and how they guide enclosure design in tools like Speaker Box Lite.
Sealed subwoofer boxes are the most classic type of loudspeaker enclosure. Compact, precise, and forgiving, they deliver a smooth, natural response — but at the cost of efficiency. Learn the real advantages, drawbacks, ideal driver parameters, and how to calculate your sealed design using Speaker Box Lite.
Learn how to change box dimensions in Speaker Box Lite, explore how the foundation figure defines the box shape, and understand the difference between Lock VB and free-dimension modes. A deep dive into practical design steps and technical background.
At the very beginning, let’s clarify our goal: in this guide we want to achieve the same result as shown in the screenshot at the top of the article. Every step described here—from choosing the driver to shaping the box and refining its look—is oriented toward recreating that exact example. Of course, you are free to adapt the process to your own taste and setup.
When building your own speaker enclosure, the sealed (or closed) box is one of the most approachable and rewarding designs. Unlike ported or band-pass enclosures, a sealed box doesn’t rely on tuned vents, ducts, or resonators. Instead, it provides a controlled acoustic suspension for the speaker driver, creating tight, accurate bass and smooth midrange response.
For small setups like a desktop or computer speaker system, this approach shines. You don’t always want booming low end that rattles the walls—you want clarity, detail, and controlled output that sits comfortably at close listening distances. That’s where a sealed bookshelf enclosure comes in. It’s compact, precise, and can be shaped to fit the exact space you have available.
Every box design starts with the driver. For our project, I’ll use the Dayton Audio TCP115-8, a 4-inch midbass woofer with parameters that make it an excellent candidate for a small sealed box.
In Speaker Box Lite, you can either select this driver directly from the built-in database (which includes thousands of drivers from different brands) or enter the manufacturer’s parameters from the datasheet. Once the driver is set, the software immediately calculates possible enclosures based on its Thiele-Small parameters.
This is where the design becomes both science and art.
On the Enclosure tab, you’ll see several starting options for calculating the internal volume of a sealed box:
Each of these methods produces a different target volume and frequency response curve. (If you’re curious about the deeper theory behind them, you can read more in this article)
For this experiment, I tried both Max flat amplitude and Max flat delay. The first gave me a result of about 1.08 liters(shown in red on the response graph), while the second suggested 2.23 liters (green curve).
But here’s the key: you are not forced to pick one of these recommendations and stop there. These are starting points, not absolute rules. Speaker Box Lite lets you overlay multiple plots so you can visually compare the results. Personally, I liked the green curve more because it delivered higher output at lower frequencies. However, the box size became larger than I could reasonably fit into my setup. That’s why I decided to experiment further with the box volume.
I decided to go with a middle ground: 1.7 liters (orange line). It’s a compromise between size and performance. The response curve is slightly lower than the 2.23-liter design, but I save half a liter of space—critical for fitting the box comfortably into my computer desk area.
This step illustrates a valuable principle in enclosure design: you balance theoretical “perfection” with practical needs and personal taste.
Once the internal volume is chosen, it’s time to bring the box to life. Switching to the 3D Box tab in Speaker Box Lite, you’re greeted with a default rectangular box.
At first glance, it’s just a simple block—but this is where creativity enters. The software allows you to change the foundation shape of the box, essentially redefining how the enclosure is extruded in 3D space.
For my desktop speaker, I wanted the box to angle slightly toward my face. That way, the driver points directly at my ears instead of firing straight ahead or upward. To achieve this, I selected the One-Side Trapezoid foundation.
You can access this option in the Structure screen under box properties. There’s a button to change the foundation type—once you press it, a menu appears where you select the trapezoid option. Immediately, the box takes on a slanted form, ready to be tailored further.
On the same screen, you can also choose the material thickness. For this build, I opted for 12 mm plywood. It’s sturdy enough for a small speaker, lightweight, and easy to work with. With these settings locked in, I saved the changes and returned to the main design view.
Now comes the part where the box transforms from theory into a piece of furniture-like design.
Speaker Box Lite offers a handy Box Bounds mode, which overlays the box with dimension labels. By enabling it, you can click directly on the height, width, or length values to modify them on the fly.
For my project, I wanted something compact but proportionate. I settled on:
The width adjusts automatically to preserve the internal volume of 1.7 liters. This is one of the conveniences of working with software instead of a calculator—you tweak, and the program maintains balance.
At this stage, the trapezoid shape was present, but I wanted the entire box to tilt—not just the front face. To do this, I redefined the bottom face of the trapezoid as the true base.
The process is straightforward: click on the desired face, open the menu, and select “Make bottom.” The box reorients itself accordingly. Now the enclosure sits naturally inclined, with the driver pointing upward and forward, directly at the listener.
It’s a subtle adjustment, but it makes all the difference when designing near-field monitors for a computer desk.
With the box prepared, it’s time to mount the driver.
On the Objects inspector screen, I selected the Dayton TCP115-8 and clicked on the inclined face where I wanted it installed. Instantly, the driver appeared on the surface.
From here, positioning is simple: press and hold the driver icon until it transforms into a blue disk, then drag it into the center of the face. Release, and the driver locks into position.
The beauty of Speaker Box Lite is how it combines simulation and CAD-like manipulation without forcing you to learn a full 3D modeling suite.
The final step to achieve the appearance I envisioned was to deepen the speaker’s mounting face. By applying a depth of 16 mm, the driver now sits recessed, giving the enclosure a professional look. The recessed mounting also creates a subtle effect: the left and right panels visually extend forward past the driver, while the driver itself feels integrated into the body rather than pasted on top.
However, my first attempt recessed the wrong edges—top and bottom instead of left and right. To fix this, I explored the Box’s edges options. This screen highlights all edges in green, and you can change their connection types.
By adjusting the butt connections for the top, bottom, left, and right panels, I achieved the correct layout: the vertical sides extended forward, framing the driver beautifully.
This step demonstrates how enclosure design isn’t just about acoustics—it’s also about aesthetics. A box that sounds great but looks awkward won’t satisfy you on your desk.
And that’s it—the enclosure is ready. To bring it into the workshop, all I needed was the Drawing screen. This feature generates a precise cutting map, complete with dimensions, material thickness, and joint types.
At this point, the project transitions from pixels to plywood. Cut the pieces, assemble them with glue and clamps, mount the driver, and you have a sealed bookshelf speaker perfectly tailored for your space.
Designing this small sealed box highlighted the flexibility of Speaker Box Lite. I didn’t simply pick a number from a chart and build blindly. Instead, I:
The result? A compact sealed enclosure that looks professional, fits neatly on my desk, and provides accurate, musical sound.
For anyone venturing into DIY speaker building, this process illustrates the synergy between physics and personal creativity. A sealed box may be simple, but within its simplicity lies endless room for refinement.
The sealed (closed) box remains one of the most versatile designs for DIY speaker projects. By combining its inherent acoustic benefits with the tools of Speaker Box Lite, you can create enclosures that not only perform well but also adapt to your personal space and style.
Whether you follow the exact steps here with the Dayton Audio TCP115-8 or choose your own driver, the process remains the same: simulate, experiment, refine, and then build.
And the best part? Every project you complete teaches you something new—not just about loudspeakers, but about the creative craft of transforming sound into something tangible.
👉 The project designed in this article is also available directly in Speaker Box Lite by the link here.
