On the assessment of subjective response to tonal content of contemporary aircraft noise

Torija Martinez, AJ; Roberts, S; Woodward, R; Flindell, IH; McKenzie, A; Self, RH

Abstract

The Effective Perceived Noise Level (EPNL) is the primary metric used for assessing subjective response to
aircraft noise. The EPNL comprises calculation of the Perceived Noise Level (in PNdB), and takes into
account flyover duration and the presence of pure tones to arrive at an adjusted EPNL value. With the
presence of a single significant tone, EPNL has been found to be reasonably effective for the assessment
of aircraft noise annoyance. Several authors have, however, suggested that EPNL is not capable of quantifying
the subjective response to aircraft noise that contains multiple complex tones. The noise source
referred to as ‘‘Buzz-saw” noise is a typical example of complex tonal content in aircraft noise with an
important effect on both cabin and community noise impact. This paper presents the results of a series
of listening tests where a number of participants were exposed to samples of aircraft noise with six variants
of aircraft engines, assumed representative of the contemporary twin engine aircraft fleet. On the
basis of the findings of these listening tests, the Aures tonality method significantly outperforms the
EPNL tone correction method when assessing the subjective response to aircraft noise during take-off
with the presence of multiple complex tones. The participants reported ‘high pitch’ as one of the least
preferable aircraft noise characteristics, and consequently, the psychoacoustics metric Sharpness was
found to be another important contributor to subjective response to the noise of two specific aircraft
engine groups (out of the six considered). The limitations of Aures tonality are discussed, in particular
for aircraft noise with both a series of complex tones spaced evenly across the frequency spectrum with
relatively even sound levels and less subjectively dominant single frequency tones (compared to broadband
noise). In line with these limitations, further work is proposed for more effective assessment of subjective
response to aircraft noise containing significant tonal content in the form of numerous closely
spaced or other complex tones.

Citation

Torija Martinez, A., Roberts, S., Woodward, R., Flindell, I., McKenzie, A., & Self, R. (2019). On the assessment of subjective response to tonal content of contemporary aircraft noise. Applied Acoustics, 146, 190-203. https://doi.org/10.1016/j.apacoust.2018.11.015

• Journal Article Type: Article
• Acceptance Date: Nov 14, 2018
• Online Publication Date: Nov 24, 2018
• Publication Date: Mar 1, 2019
• Deposit Date: Dec 2, 2019
• Publicly Available Date: Dec 2, 2019
• Journal: Applied Acoustics
• Print ISSN: 0003-682X
• Publisher: Elsevier
• Volume: 146
• Pages: 190-203
• DOI: https://doi.org/10.1016/j.apacoust.2018.11.015
• Publisher URL: https://doi.org/10.1016/j.apacoust.2018.11.015
• Related Public URLs: https://www.sciencedirect.com/journal/applied-acoustics
• Additional Information: Additional Information : This paper led to several invited talks: 2019 Title: Novel Aircraft Noise Modelling and Psychoacoustic based Optimisation Event: Penn State Center for Acoustics and Vibration Spring Workshop, State College, Pennsylvania, USA. 7-8 May 2019. 2019 Title: ISVR activity for assessing the noise impacts of drones and urban air mobility Event: Spring 2019 NASA Acoustics Technical Working Group Meeting, Hampton, VA, USA. 9-10 April 2019. 2018 Title: Impact assessment of aircraft noise with high content in complex tones Event: 22nd Workshop of the Aeroacoustics Specialist Committee of the CEAS – Future Aircraft Design and Noise Impact, Amsterdam, Netherlands. 6-7 September 2018. Also, it led to international collaborations: 2018 – Present Virtual Acoustic Simulation Technology for Community Noise (VASTCON) Technical Working Group (TWG). Contacts: [e-mail] / [e-mail] 2018 – Present NASA Urban Air Mobility Noise Working Group. Contact: [e-mail] / [e-mail]; Funders : Engineering and Physical Sciences Research Council (EPSRC);Innovate UK; Projects : AIRPORT CAPACITY CONSEQUENCES LEVERAGING AVIATION INTEGRATED MODELLING (ACCLAIM);ROLLS ROYCE SILOET II PROJECT 13 ENGINE INSTALLATION ANALYTICS FOR FUTURE NOVEL ARCHITECTURES; Grant Number: EP/M026868/1; Grant Number: TSB/113086