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40 mm loudspeaker envelope (the speaker in the thermoacoustic driver cap)
How big is a 40 mm speaker, and how does it sit in a thermoacoustic driver cap? · Hardware · basis: Overall Ø40 × 25 and the step diameters measured from the manufacturer's published model of a 40 mm speaker (Adafruit #3968); drawn as a stepped envelope, nothing copied
Long Earth Society build part. The speaker I use as the alternator on my thermoacoustic engines. The engines
Exact dimensions. Every file is drawn at true size with no printing tolerance. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your printer's or process's clearance before making the part. Mating features
- sizes
- 4 in table
Notes
- A stepped envelope of a common 40 mm speaker: the space it takes, not its parts. Front rim Ø40 × 3 with the cone behind it, a Ø34 × 4 step, the Ø28 basket and the Ø20 magnet; 25 mm overall.
- In the 2 in driver cap it sits rim down in the Ø40 × 6 socket, cone toward the gas through the cap's Ø28 port; the basket and magnet stand above the cap.
- As an alternator: the gas pressure moves the cone, the voice coil moves in the magnet's field and gives a voltage at the terminals. A small speaker gives milliwatts to a fraction of a watt; see the build lists for the model's acoustic power at the cap.
Sizes
| feature | value |
|---|---|
| step 1 | Ø40 from 0 to 3 |
| step 2 | Ø34 from 3 to 7 |
| step 3 | Ø28 from 7 to 17 |
| step 4 | Ø20 from 17 to 25 |
Mating features
Drawn at the exact size. Open press, slide, run and socket features by your process's clearance; leave designed gaps and clamp fits as drawn.
| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| front rim | Ø40 × 3 | Ø40 × 6 socket of the 2 in driver cap | socket | all |
| basket and magnet | Ø34 / Ø28 / Ø20 | space above the driver cap (no contact) | designed | all |
Where the files are
Other publishers' files are linked, not hosted. "verify" = check the license at the link before commercial use.
| Adafruit (CAD parts repository, MIT) | #3968 Speaker 40mm: overall Ø40 × 25 and the step diameters measured from the published model; nothing copied | STEP | MIT; dimensions only |
| Long Earth Society | Engine builds | web, video | LES site |
Free files
★ Free files 1 parts. Generated by Xem Studio from the standard; threads are plain cylinders at major diameter. CC BY 4.0. index.json
| speaker-envelope-40mm | 40 mm loudspeaker envelope: front rim Ø40 × 3 (cone side at z = 0), Ø34 × 4, basket Ø28 × 10, magnet Ø20 × 8; 25 overall | STEP · STL |
Plain text: sheet.txt · JSON: /api/geometry?object=loudspeaker-envelope-40mm
How it fits
In these build lists
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Questions
Is this the speaker's real shape?
It is its envelope: every step is the largest diameter of the speaker over that height, so anything that clears the envelope clears the speaker.