2.5-inch Two-Way Mini Desktop Speaker - Sugar Cube v1.0

The fourth speaker in this series has arrived, the smallest yet among all 3D-printed enclosure projects. The Sugar Cube V1.0 enclosure is printable even on the A1 mini.

It utilizes a 30-yuan Kaleidoscope Track Speaker, equivalent to 2.5 inches. A two-way design is employed, paired with a 12-yuan silk dome tweeter. Note that the tweeter requires parallel reverse connection, with a capacitor added at the positive terminal.

Six enclosure designs were prototyped, including a transmission line bass-reflex enclosure, but unfortunately, the small speaker proved inadequate. The design was iteratively refined to its current iteration.

Low-frequency response is extended to 75Hz, although the small speaker's limitations result in somewhat thin bass. A subwoofer upgrade is planned. The 2.1 amplifier board from the previous list will finally be put to use for this 0.1 upgrade.

This amplifier board allows for independent bass gain adjustment on each channel. With the Sugar Cube, setting the gain to the 12 o'clock position enhances the low-frequency output.

Listen tests are available: 2.5-inch two-way Sugar Cube vs 6.5-inch coaxial KEF IQ3.
For optimal sound, set the Bilibili video volume to 100% and computer system volume to 50%. Headphone listening is recommended.

The sound achieves approximately 75% of the live listening experience (lacking the ambient surround sound and impactful bass pressure of a live setting).

A key detail: the second knob from the right on the amplifier board can be adjusted to the 12 o'clock position to enhance the bass response of the large rubber surround of the track speaker.

I. Refinements

1. A miniature enclosure delivering exceptional performance. Printable on the A1 mini.

2. Two-way design. For desktop listening, ear height is typically elevated. Therefore, the tweeter is positioned below the midrange driver, aligning the sound axis upwards towards the ear.

3. 140mm duct length, 1.2L internal volume, low-frequency response down to 75Hz. Bass-reflex designs with larger, longer ducts were discarded due to suboptimal frequency response and insufficient speaker output.

4. The duct is printed as a single piece, eliminating potential air leaks from later assembly.

II. Assembly Overview

1. Print the left and right enclosures, totaling four print plates.

2. Pre-attach the terminal posts to the enclosure interior using 704 white glue, ensuring complete sealing around the edges to prevent leaks.

3. Apply EVA foam tape to both the midrange and tweeter for improved sealing.

4. Connect the midrange driver normally; positive to positive and negative to negative. Reverse the tweeter connections: negative to the positive terminal and positive to the negative terminal. Remember to add a 3.3µF capacitor in parallel with the tweeter's negative terminal.

5. Apply EVA tape to the side panel flange for airtight sealing before attaching the screws.

6. For optimal performance, adding damping material within the enclosure and wrapping the internal wiring in EVA foam tape is recommended.

III. Bill of Materials

1. Kraft 704 Silicone Rubber White Glue, Specification 704 [White Semi-Fluid]
[One unit] 4.5 yuan

2. Kaleidoscope Rectangular Track Speaker
[One pair] 60 yuan

3. Silk Dome Tweeter
[One pair] 24 yuan

4. Pure Copper Speaker Terminal Wire
[2 strands (1 strand, 2 cores)] 3 yuan

5. Self-Tapping Screws BA4*12
[50 units] 5 yuan

6. EVA Sealing Strip Foam Tape, Black
[5 meters] 4.85 yuan

7. Automotive Sound Insulation Dampening Mat, 0.5X0.8m
[One sheet] 10.9 yuan

8. Dual Head Professional Speaker Amplifier Binding Post Terminal Speaker Banana Plug Integrated Red and Black Connector
[One pair] 5.76 yuan

9. 3.3µF Capacitor
[One pair] 5 yuan

A. 2.1 Channel Bluetooth 5.0 Digital Amplifier Board 2*50W+100W
[One set] 64.8 yuan

B. 24V 10A Power Cord
[One unit] 46.8 yuan

(For Taobao links to the above, please refer to the document's parts list)