Lessons & roadmap¶
Recommendations for builders¶
- Measure the impedance before anything else. A 50 Ω resistor and two jack leads identify the driver version and give the real port tuning in minutes (Impedance jig).
- Don't copy the 43 Hz tuning for the Aiyima. Aim for ≈ 50 Hz; a 175 mm total port gave ≈ 48 Hz and a flat bass in this box. Cut long, measure, trim.
- Place damping by the mode, not by the panel. Thick, loose fill at mid-height for the 350 Hz mode; wool on the back panel for the ~950 Hz depth mode. One thin layer alone does little.
- The budget damping layout works: one layer of sheep's wool fleece on the back panel plus 50 g of pillow fill in a wool pocket across the middle third of the height.
- Build the back panel as drawn — 292 × 482 mm, gasket and screws — and seal the OSB inside. A friction fit leaks and shifts the bass every time it's refitted.
- Stop before the impedance dip disappears. When the dip between the bass peaks is down to ~1 Ω, more damping costs bass.
- Make the setup repeatable before you measure the speaker: floor marks, taped knobs, a loopback reference, fingerprints at every session.
Conclusions¶
- Measurement makes it verifiable; the ears make it final. The curves say the alignment is right; the listening test says it sounds more balanced. Tuning further would trade evenness against bass quantity — a matter of taste, not of right or wrong.
- Balance, not quantity. For more bass level the levers are placement (closer to a wall, as the original design intends), a gentle EQ shelf, or loudness compensation — all safe once the protective high-pass sits at 0.75 × Fb.
- The first tube cut landed on target. Partly luck — but the prediction came from the measured tuning, and three independent checks (port near field, bass sum, impedance) agree on ≈ 48 Hz.
Roadmap¶
| Step | Status |
|---|---|
| 1 — Damping (speaker L) | done |
| 2 — Port tube (speaker L) | done |
| Speaker R: same damping and 175 mm port, check measurement | next |
| Finishing: tube glued, back panel gasket + screws, neat damping, one confirming session | next |
| 3 — Correction EQ for the treble peaks (~6 and ~10.5 kHz) | planned |
| Room: placement and room correction at the listening seat | planned |