Waveguide Geometry

Status

Currently in the measuring phase: Prototype B’s waveguide is built and its directivity is being swept against Prototype A in the lab.

Objective

Find the smallest waveguide whose flare profile matches the mid-bass driver’s directivity from 1.5 kHz to 4 kHz. Size costs baffle real estate and diffraction; flare rate costs nothing but simulation time — so the search space is flare geometry at fixed throat.

Method

1. Simulate candidate flare profiles (conical, tractrix, blended) in BEM.
2. Rank by directivity match at the crossover and mouth diffraction.
3. Print and build the two best candidates as full prototypes (A and B).
4. Sweep horizontal/vertical directivity on both and compare against the simulation predictions.

Results so far

Prototype B’s blended flare tracks the simulated directivity within a couple of degrees through the crossover band, and the 2–3 kHz artefact present on Prototype A disappears. The full dataset is published (as clearly labelled sample data pending bench verification) in the Reference One measurement archive.

Next steps

• Vertical-plane sweeps at listening-height offset.
• Mouth-edge diffraction treatment (small-radius fillet) and re-measurement.
• Decide production geometry once both planes validate against simulation.