Method of satisfaction based on-board acoustic comfort classification and its applications

Acoustic comfort is an important factor that passengers and crew usually consider for their on-board wellness. The classification is an efficient way to show the level of acoustic comfort on board. Most of the existing classification approaches of on-board noise in different spaces are based on the decibel based indicators which describes the loudness. However, acoustic comfort is not only relevant to decibel based indicators but also perceptual attributes such as timbre and pitch. In order to provide more perceptual support, a satisfaction based classification method for acoustic comfort is modified, determining the limits of the noise in different task-oriented spaces on board. Perceptual assessments were carried out to obtain numerical values for acoustic comfort as noise comfort index (NCI) and measured satisfaction (S_M) of each noise sample. Analysis made on these two descriptors indicated that the NCI has a strong relationship with S_M. Therefore, satisfaction can be regarded as a basic perceptual guideline to classify the acoustic comfort and determine the limits of each level for each task-oriented space. A linear acoustic comfort model was established to predict the NCI based on the acoustic parameters. Comparison with the previous classification of on-board noise showed that there is a mismatch between the NCI and sound pressure level (SPL), and NCI can not be fully represented by SPL.