Computational design applied to small room acoustics: creating and evaluating custom solutions

This paper evaluates a design procedure which is able to scale one-dimensional quadratic-residue diffusers, with integrated Helmholtz resonators.

These acoustic structures can be tuned to room modes while fitting within a specified volume. An algorithmic solver is used to control geometric parameters in order to achieve a target frequency. The effect of the diffuser on a room is estimated using Pachyderm. Values obtained with simplified models, that make use of analytically derived coefficients, are compared with those obtained by simulating the full geometry. The predictive power of the simplified modeling made it preferable over simulating the full geometry in comparable scenarios. CFD simulations and measurements taken from a 1:1 scale prototype, are used to evaluate the applicability of lumped mass models to predict resonance frequency and absorption of slit Helmholtz resonators. Although the obtained results remain inconclusive, they indicate a higher inertial attached length for semi-infinite slit resonators, than typically found in literature. If these results can be validated, then the procedure should provide reliable designs.