Extension of Reflection-Free Region for Loudspeaker Measurements

Vanderkooy J. Extension of Reflection-Free Region for Loudspeaker Measurements. In: Express Paper. Audio Engineering Society; 2025. Paper 309. Available from: https://aes.org/publications/elibrary-page/?id=22860

@inproceedings{Vanderkooy2025_22860,
  author = {Vanderkooy, John},
  title = {{Extension of Reflection-Free Region for Loudspeaker Measurements}},
  note = {Paper 309},
  year = {2025},
  month = may,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=22860}
}

TY  - CPAPER
TI  - Extension of Reflection-Free Region for Loudspeaker Measurements
AU  - Vanderkooy, John
M1  - Paper 309
PY  - 2025
DA  - 2025/05/12
UR  - https://aes.org/publications/elibrary-page/?id=22860
PB  - Audio Engineering Society
LA  - en
AB  - If loudspeaker measurements are carried out elevated over a flat, very reflective surface with no nearby obstacles, the recovered impulse response will contain the direct response and one clean delayed reflection. Many loudspeakers are omnidirectional at low frequencies, having a clear acoustic centre, and this reflection will have a low-frequency behaviour that is essentially the same as its direct response, except the amplitude will be down by a 1/r factor. We derive a simple algorithm that iteratively allows this reflection to be cancelled, so that the response of the loudspeaker will be valid to lower frequencies than before, complementing the usual high-frequency response obtained from simple time-truncation of the impulse response. The method is explained, discussed, and illustrated with a two-way system measured over a flat, sealed driveway surface.
ER  -