Quantifying the audible differences in measured and auralized aircraft sounds

This paper aims to present a way with which audible differences in measured and auralized (i.e. aurally simulated) aircraft noise can be quantified. The purpose of the study is to find a means with which the subjective differences between measured and synthesized sounds can be expressed in an objective manner. The quantification would firstly enable developers of auralization technology to identify more concretely in which aspects the differences exist, in order to make the auralizations sound more realistic. The quantification would secondly aid in developing a means of distinguishing between aircraft sounds in general, beyond the conventional metrics of A-weighted level (dBA) or Effective Perceived Noise Level (EPNL). Such a capability can allow target functions to be developed with which aircraft can be optimized for specific, more acceptable sounds. As used widely in other industries such as the automotive sector, use of sound quality metrics is made to quantify the differences in the quality of the sounds. The comparison is carried out in terms of both conventional and sound quality metrics for the audio of a reference aircraft, which has been measured and auralized over the same flight paths at a noise monitoring station in the airport vicinity.