Thermoacoustic driver cap: ISO 2852 cap with a Ø40 speaker socket, 1.5, 2 and 3 in — dimension sheet
Source: Xem Studio, https://xemstudio.com/objects/thermoacoustic-driver-cap/  (CC BY 4.0)
Basis: ISO 2852 cap face; Ø40 × 6 socket for a 40 mm speaker frame; Ø28 opening to the tube
Catalog version: 2026-10-20

Sizes: see table below
- An ISO 2852 end cap that holds a 40 mm speaker on the resonator: as a driver it makes a thermoacoustic refrigerator, as a load it turns the engine's sound into a few milliwatts.
- On the back of the 6 mm cap: a Ø48 × 8 boss with a Ø40 socket 6 mm deep (floor 8 mm above the face) and a Ø28 opening through to the tube. Overall 14 mm.
- Flange Ø50.5 / 64.0 / 91.0 for 1.5 / 2 / 3 in.

size_in  flange_od_mm  speaker_socket_mm  opening_mm  height_mm
1.5  50.5  Ø40 × 6  28  14
2  64.0  Ø40 × 6  28  14
3  91.0  Ø40 × 6  28  14

Files elsewhere (not hosted by Xem Studio; license as stated by the publisher):
- Wikipedia: Thermoacoustic heat engine — web — CC BY-SA 4.0 (text) — https://en.wikipedia.org/wiki/Thermoacoustic_heat_engine
- G. W. Swift (LANL): Thermoacoustics: A Unifying Perspective for Some Engines and Refrigerators (textbook; DeltaEC software free) — web, software — LANL [verify license at link] — https://www.lanl.gov/org/ddste/aldps/materials-physics-applications/condensed-matter-magnet-science/thermoacoustics/
- NASA (NTRS, public domain): Thermoacoustic Stirling heat engine for space power — PDF — US Government work, public domain — https://ntrs.nasa.gov/search?q=thermoacoustic%20Stirling
- Long Earth Society: Engine builds — web, video — LES site — https://longearthsociety.com/engineering/

Free files (CC BY 4.0, Xem Studio; STEP + STL, 3 parts): https://xemstudio.com/files/hardware/thermoacoustic-driver-cap/index.json
API: https://xemstudio.com/api/geometry?object=thermoacoustic-driver-cap