Loudness models in the very low frequency range: application to the prediction of airplane cockpit noise comfort

Aircraft interior noise is a major design stake with respect to airline requirements for passenger and crew comfort. A study dealing with airplane cockpit noise annoyance had shown that loudness computed according to ISO 532-B standard was a good gauge of qualitative evaluation. This was not true for loudness computed according to ANSI S3.4 standard. It seems that this was due to differences of the two models for very low frequency sounds, as these models were adjusted to fit to different iso-loudness curves. In order to check this hypothesis, direct loudness estimations will be presented in the low frequency range (from 35 Hz to 65 Hz). These estimations will be compared to predictions given by the two models.