The Design of Broadband Acoustic Metamaterial Lenses via Differentiable Simulations

Todd F, Masri M, Oxnard S, Hobden L. The Design of Broadband Acoustic Metamaterial Lenses via Differentiable Simulations. In: 2026 AES 6th International Automotive Audio Conference. Audio Engineering Society; 2026. Paper 23. Available from: https://aes.org/publications/elibrary-page/?id=23416

@inproceedings{Todd2026_23416,
  author = {Todd, Fraser and Masri, Mahmoud and Oxnard, Stephen and Hobden, Laurence},
  title = {{The Design of Broadband Acoustic Metamaterial Lenses via Differentiable Simulations}},
  booktitle = {2026 AES 6th International Automotive Audio Conference},
  note = {Paper 23},
  year = {2026},
  month = jul,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=23416}
}

TY  - CPAPER
TI  - The Design of Broadband Acoustic Metamaterial Lenses via Differentiable Simulations
AU  - Todd, Fraser
AU  - Masri, Mahmoud
AU  - Oxnard, Stephen
AU  - Hobden, Laurence
T2  - 2026 AES 6th International Automotive Audio Conference
M1  - Paper 23
PY  - 2026
DA  - 2026/07/29
UR  - https://aes.org/publications/elibrary-page/?id=23416
PB  - Audio Engineering Society
LA  - en
AB  - A core challenge of acoustically optimising an automotive sound system is realizing a balance between ideal and viable loudspeaker placement. Placement is largely influenced by structural, aesthetic and safety design considerations, leading to non-ideal acoustic response characteristics within a given car cabin. For instance, drive units are often oriented off-axis from listening regions. To fully benefit from a transducers performance, the on-axis response is desirable at the listening location. This work presents the design and evaluation of an acoustic metamaterial lens that performs broadband beam steering on an incoming wavefront. Through a series of acoustical simulations and associated geometry optimisation routines, it is shown that the lens can be used to steer the on-axis response of a transducer towards an off-axis direction. Results drawn from simulations and physical measurements demonstrate that wavefronts passing through the lens are steered up to 12.5 off-axis over a bandwidth of f _ [3:7] kHz with an overall reduction in sensitivity of < 5 dBSPL relative to the original on-axis (no lens) response.
ER  -