sound engineering for aircraft · università degli studi roma tre ... fly-over events were...

��SEFA

Sound Engineering For Aircraft

��SEFA

Content

• SEFA basic features• Partnership

• SEFA objectives

• Starting conditions

• Main achievements• Main achievements• Methods and results of psychometric tests

• Aircraft target sound design

• Development of a virtual aircraft tool

• Developments of a virtual listener tool

• Aircraft sound quality design criteria

• Conclusions

��SEFASEFA basics

Title: Sound Engineering For AircraftAcronym: SEFAContract Nr.: AST-CT-2003-502865Total Costs: 5.9 M€EU Contribution: 3.9 M€Starting Date: 01/02/2004Duration: 36 months + 5monthsWeb-site: https://cms.x-noise.net/sefa/Portal/ (internal)Web-site: https://cms.x-noise.net/sefa/Portal/ (internal)

Coordinator: EADS IW

Contact: Dr. Roger [email protected]

EC Officer: Per [email protected]

��SEFASEFA partnership

• Dornier GmbH � EADS• Snecma Moteurs• Deutsches Zentrum für Luft- und Raumfahrt• SASS acoustic research & design GmbH• Metravib RDS• Office National d'Etudes et de Recherches Aérospatiales• Institut of Sound and Vibration

Research University of Southampton• Royal Institue of Technology• Alenia Aeronautica S.p.A.• Forschungsgesellschaft für Arbeitsschutz und

ArbeitsphysiologieArbeitsphysiologie• Budapest Universtity of Technology and Economics• Dipartimento di Ingegneria Mecc. e Ind.

Università degli Studi Roma Tre• Instituto Superior Técnico• EADS Deutschland GmbH, CRC• Université de Cergy Pontoise• Institue National de Recherche sur les

Transports et leur Securité• Leuven Measurement Systems International N.V.• C.R.F. Società Consortile per Azioni• Institut für Technische und Angewandte Physik GmbH• Universita' di Napoli "Federico II" DPA

��SEFASound Engineering for Aircraft… is the first approach applying

sound engineering methods to control exterior aircraft noise.

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Objectives

WP4WP5

ExpertPanel

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Identification of least preferred characteristics of aircraft noise

Definition of preferred aircraft sounds

Development of design criteria for preferred

aircraft sounds

Listening tests…………Target sound design……..…Design criteria

WP6WP3

WP2

��SEFA

WP4virtual a/c

tool!!!!!!

WP5virtual

listener

Starting conditions

• Large competence in tool development

• No methods for aircraft source noise synthesis

• Mathematics and statistics well known

• Never before applied to subjects listening to aircraft flyover sounds

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• Large competence and experience in noise effects

• Limited experience for flyover sound quality listening tests in the laboratory

WP6designcritera

WP3sounddesign

WP2psychometric

tests

• Strong experience from automotive applications• Limited experience for flyover sound design• No suited flyover recordings available

��SEFAWP2 achievements / Psychometric tests

Methods development for psychometric listening test s• Development of test procedures for Semantic Differential as well as a

Paired Comparison tests including • General questionnaire (personal data as age, gender, housing,

occupation etc.) • Noise Sensitivity questionnaire NoiSeQ (individual noise sensitivity

of each subject)• Mood questionnaire (current mood of a subject)• Audiometric pre-screening (hearing ability of a subject)

• Translation of the questionnaires into 7 languages and integration of one common software tool for a standardized procedure in 8 different laboratories

• Definition of common hardware for testing

WP2psychometric

tests

pilot tests, DLR

• Definition of common hardware for testing• Pilot studies provided information on

• subjects’ physical and mental fatigue during listening (max. 35 comparisons/session)

• the importance of pre-training with sound examples

Methods validation• Paired Comparison and Semantic Differential both are adequate methods

to describe human perceptional space towards current aircraft sounds• The laboratory standardization with common software and instructions

was very successful• Cultural effects, age, gender, noise sensitivity and the status of being an

airport resident have no relevance on the judgment on aircraft sounds


Test series with matrix of current, recorded sounds• For the subjects differences among the aircraft sounds were

detectable, but the differences were small. Convincing dependences to psychoacoustic and clear standards for target sound design could not be derived exclusively.

WP2psychometric

tests

Configs Business Regional single aisle LR twin LR quad

#03T

-#04TA

BPR < 3

3 < BPR < 5

#02T

#06T

#01T

-#05TA, #15A

#23TA FT#07T, #17A

#08TA#09TA

#10T, #18A#11TA#12TA

FT - #22TA

FT FT

#13TA, #19A#14T, #20A

3 < BPR < 5

BPR 6

8 < BPR < 9

BPR > 10

Props

#16A

FT

FT = future target configurationsT = take-off A = approach


WP2psychometric

tests


#03T

-#04TA

BPR < 3

3 < BPR < 5

#02T

#06T

#01T

Test series focusing on sound modifications of a/c #12 and #22• Check the influence of buzz-saw-tones (±5dB), fan tones (±5dB),

broadband noise below 315Hz (±4dB), broadband noise above 315Hz (±4dB) and overall level (±3dB) vs. the original sound

-#05TA, #15A

#23TA FT#07T, #17A

#08TA#09TA

#10T, #18A#11TA#12TA

FT - #22TA

FT FT

#13TA, #19A#14T, #20A

3 < BPR < 5

BPR 6

8 < BPR < 9

BPR > 10

Props

#16A

FT


WP2psychometric

tests


#03T

-#04TA

BPR < 3

3 < BPR < 5

#02T

#06T

#01T

Test series applying combined sound modifications• Check the combined influence of buzz-saw, fan, propeller and

turbine tones and jet noise for a/c’s #5, #8, #13, #11

tone 1tone 1-

#05AT, #15A

#23TA FT#07T, #17A

#08TA#09TA

#10T, #18A#11TA#12TA

FT - #22TA

FT FT

#13TA, #19A#14T, #20A

3 < BPR < 5

BPR 6

8 < BPR < 9

BPR > 10

Props

#16A

FT

Ref. -4dB0dB

-8dB0dB

0dB-4dB

0dB-8dB

turb

ine

tone

-4dB-4dB

-8dB-4dB

-4dB-8dB

-8dB-8dB

propeller tone

Ref. -4dB0dB

-8dB0dB

0dB-4dB

0dB-8dB

turb

ine

tone

-4dB-4dB

-8dB-4dB

-4dB-8dB

-8dB-8dB

propeller tone

Ref. -6dB0dB

-12dB0dB

0dB-6dB

0dB-12dB

tone

2 -6dB-6dB

-12dB-6dB

-6dB-12dB

-12dB-12dB

Ref. -6dB0dB

-12dB0dB

0dB-6dB

0dB-12dB

tone

2 -6dB-6dB

-12dB-6dB

-6dB-12dB

-12dB-12dB

Ref. -4dB0dB

-8dB0dB

0dB-4dB

0dB-8dBbu

zz-s

aw to

nes

-4dB-4dB

-8dB-4dB

-4dB-8dB

-8dB-8dB

fan tones

Ref. -4dB0dB

-8dB0dB

0dB-4dB

0dB-8dBbu

zz-s

aw to

nes

-4dB-4dB

-8dB-4dB

-4dB-8dB

-8dB-8dB

fan tones

#05A

#08TA

#13TA

Ref.-3dB0dB0dB

-6dB0dB0dB

-9dB0dB0dB

0dB-3dB0dB

0dB-6dB0dB

0dB-9dB0dB

-3dB-3dB0dB

-6dB-3dB0dB

-9dB-3dB0dB

-3dB-6dB0dB

-6dB-6dB0dB

-9dB-6dB0dB

-3dB-9dB0dB

-6dB-9dB0dB

-9dB-9dB0dB

buzz

-saw

tone

slo

w freq

. jet

fan tones

Ref.-3dB0dB0dB

-6dB0dB0dB

-9dB0dB0dB

0dB-3dB0dB

0dB-6dB0dB

0dB-9dB0dB

-3dB-3dB0dB

-6dB-3dB0dB

-9dB-3dB0dB

-3dB-6dB0dB

-6dB-6dB0dB

-9dB-6dB0dB

-3dB-9dB0dB

-6dB-9dB0dB

-9dB-9dB0dB

buzz

-saw

tone

slo

w freq

. jet

fan tones

Ref.-3dB0dB0dB

-6dB0dB0dB

-9dB0dB0dB

0dB-3dB0dB

0dB-6dB0dB

0dB-9dB0dB

-3dB-3dB0dB

-6dB-3dB0dB

-9dB-3dB0dB

-3dB-6dB0dB

-6dB-6dB0dB

-9dB-6dB0dB

-3dB-9dB0dB

-6dB-9dB0dB

-9dB-9dB0dB

buzz

-saw

tone

slo

w freq

. jet

fan tones

#11T


WP2psychometric

tests

Test series applying combined sound modifications

• The scaling results were aircraft specific, i.e. effects were different in kind and order of magnitude depending on the perceptual frame of reference. The frame of reference is influenced by e.g. the sound features of the reference sound and the context in which subjects are asked to judge them.

• A ranking of modifications leading to specific recommendations was derived.

��SEFAWP3 achievements / Target sound design

Generation of a sound data base

• A sample of 238 fly-over AC-sounds (arrival and take-off) was measured at three different airports in Europe (Germany and United Kingdom) using a binaural microphone technique. Fly-over events were documented by standardized photography and by airport fly-movement records.

• From the broad sample a core matrix of 32 sounds representing 23 aircraft (business, regional, short and medium range twin, long range twin, long range quad) was selected for further signal processing.

WP3sounddesign

field recordingsSASS


Signal processing

• For synthesis of aircraft sounds new methods were developed based on

• spectral decomposition

• non-linear filtering

• Based on original flyover recordings a database of several hundred modified aircraft sounds was generated using both methods

WP3sounddesign

• These modified sounds were partly EPNL equalized and included an objective psychoacoustic analysis.

• Airframe noise predictions and synthesis.

��SEFA

2

WP3 achievements / Target sound design

LMS spectral decomposition and synthesis method WP3sounddesign

broadband noise in third octave bands

Generation of sound modifications e.g. by modification of broadband noise spectrum over time and/or modification of tonal components

1

2

3 4

recorded sound Doppler shifted tones + third octave bands

synthesized sound withinterference pattern

+

dopplershifted tones


SASS filtering method WP3sounddesign

Generation of a set of spectrally derived dynamic steering parameters which are tuned to the tonal components

Generation of dynamically changing filter parameters amplitude, frequency and bandwidth

��SEFAWP4 achievements / Virtual aircraft tool

Development of a virtual aircraft tool VACD

• Providing realistic, audible flyover sounds for virtual aircraft configurations in order to generate a feedback link from target sounds to aircraft configuration

θ0Sθ4R , R

WP4virtual a/c

tool

• Assembly of noise source data on component level

• Synthesize the source components on a time-depending flight path

• Include Doppler effect

( d B )

Je t C o m b u s t i o n

F a n

T u r b i n e

( d B )( d B )

Je tJe t C o m b u s t i o n

F a n

T u r b i n e

LEVEL

θ1

θ2

θ3

R0, R1

θR0

R1

α1

α2R

flyover sound

• Include atmospheric absorption effects

• Include ground reflection effects

• Include indoor/outdoor propagation effects

• Generate a tool architecture including a GUI (graphical user interface)

• Qualification, validation and application

F R E Q U E N C Y ( H z )F R E Q U E N C Y ( H z )

��SEFAWP4 achievements / Virtual aircraft tool

Development of a virtual aircraft tool VACD WP4virtual a/c

tool• Assembly of noise source

data on component level

• Synthesize the source components on a time-depending flight path

• Include Doppler effect VACD graphical • Include Doppler effect

• Include atmospheric absorption effects

• Include ground reflection effects

VACD graphical user interface

��SEFAWP5 achievements / Virtual listener tool

Development of a virtual listener tool VLIS

• Providing the average subjective evaluation of a flyover sound with respect to a preference scaling in order to replace future listening tests

• Assembly of WP2 data for tool development

• Optimization of data reduction procedure and selection of most appropriate descriptors

• Set up of mathematical models

WP5virtual

listener

reduced parameterset

flyover_sound.wav

mathematical • Set up of mathematical models

• Galois-Lattice theory

• Artificial Neural Network

• Statistical Regression Analysis

• Qualification, validation and application

mathematical model

knowledge data base

preference prediction

��SEFAWP5 achievements / Virtual listener tool

Validation of VLIS

• Relevant (psycho-)acoustical parameters have been identified which allow good predictions of subjective response.

• The best performing parameters are the same as those identified by WP2.

• Performance limitations are due to the necessarily limited range of aircraft noise stimuli which could be tested even within the large SEFA test program.

WP5virtual

listener

VLIS graphical user interface VLIS validation vs. test results

��SEFAWP6 achievements / Design criteria

Definition of design criteria for optimized target sounds

• Within SEFA results the derived target sounds were aircraft type specific. For this reason global aircraft design guidelines cannot yet be defined.

• Guidelines for airframe and engine design and flight procedures have been derived according to aircraft specific phenomena. For example, for the aircraft #11 reference configuration it turned out that a reduction of the buzz-saw noise components leads to large benefits for the noise effects while it has only minor influence on EPNL. This would lead to the recommendation to adapt the rpm/bypass ratio or to integrate a zero-

WP6designcritera

recommendation to adapt the rpm/bypass ratio or to integrate a zero-splice liner.

• A multidisciplinary optimization approach (MDO) has been extended on target sound design based on a sound similarity index implemented as a merit function.

��SEFAConclusions

Lessons learned

• The differentiation and scaling of aircraft sounds is a very difficult task for typical listeners. One of the reasons is that full flyover events are continuously changing during a typical 40 sec. duration.

• Effects of specific sound features (e.g. fan tones) are largely depending on the overall sound composition of a flyover event, i.e. a number of other tonal and broadband components.

• Global target sound optimization has more dimensions than anticipated at the beginning of SEFA.

Achievements and results

• Validated methods for sound quality listening tests

• Validated aircraft flyover sound synthesizing methods for target sound design

• Validated tools estimating sound quality effects (VLIS) and the corresponding aircraft configuration

• A number of sound modifications have been identified which have an effect on sound quality additional to the sound level.

��SEFAPublications1. L. Chaudron, J.-L. Gobert, N. Maille, U. Müller, F. Marki, R. Drobietz: Sound Engineering For Aircraft: the Virtual Resident project, The 18th International Congress on Acoustics, April 4 to 9,

2004 Kyoto, Japan2. U. Iemma, M. Diez, G. Bernardini, L. Morino: Community noise impact on conceptual optimal design of innovative airplanes, CEAS conference “aeroacoustics of new aircraft & engine

configurations”, November 2004 Budapest3. P. Van de Ponseele, K. Janssens: A model-based sound synthesis approach for aircraft flyover noise, International Workshop on product Sound Quality, 29-30 March 2005, Daejeon, Korea.4. U. Iemma, M. Diez, L. Morino: Community noise impact on the conceptual design of innovative aircraft configurations, AIAA conference 2005, Monterrey5. R. Bisping: Sound Design of Aircraft Sounds, DAGA 20056. P. Chevret, J. Périsse, Ch. Thirard: On the evaluation of the quality of a sound synthesis : capabilities of classical psychoacoustic indicators, Managing uncertainties in noise measurement and

prediction, Le mans – 27-29 june 20057. R. Bisping: Aircraft Target Sound Design, 12th ICSV July 2005, Lisbon8. K. Janssens, A. Vecchio, H. Van der Auweraer and F. Deblauwe, 2005. Synthesis of aircraft flyover noise. Internoise Conference, Rio de Janeiro, Brazil, 7-10 August, 2005.9. K. Janssens, A. Vecchio, P. Van de Ponseele, H. Van der Auweraer: Data-based modeling and synthesis of aircraft flyover noise, Forum Acusticum Conference, 29 August - 2 September

2005, Budapest.10. B. Barbot, C. Lavandier, P. Cheminée: Aircraft Noise Perceptual Space, Proceedings of the Forum Acusticum, 29. Aug. – 2. Sept. 2005, Budapest.11. K. Janssens, P. Van de Ponseele, A. Vecchio, H. Van der Auweraer, B. Flynn: Model-based synthesis of aircraft flyover noise, SAE 2005 World Aerospace Congress, 3-6 October 2005,

Grapevine, Texas, US.12. K. Janssens, P. Van de Ponseele, A. Vecchio, H. Van der Auweraer, B. Flynn and D. Berckmans, 2005. Model-based synthesis of noise in aircrafts. SAE 2005 Transactions Journal of

Aerospace, paper 2005-01-3404, p.1362-1367.13. U. Iemma, M. Diez, V. Marchese: Sculpting the sound of aircraft: a novel MDO approach for noise annoyance alleviation, ICRAT 200614. M. Schütte, U. Müller, R. Drobietz: An European Project - Sound Engineering for Aircraft (SEFA), World congress of ergonomics, July 2006, Maastricht.15. L. Brocolini, C. Lavandier, B. Barbot: Influence du contexte sonore sur la gene occasionnee par le bruit des avions sur l’accomplissement d’une tache, CFA 200616. Patrik Chevret, Jocelyn Périsse, Christophe Thirard, Rudolf Maier, Jean-Michel Nogues, A signal processing model for the sound synthesis of Aircraft, XVe COLLOQUE chocs et bruit, 14 15 et

16 JUIN 2006, ECOLE CENTRALE DE LYON17. Janssens K., Vecchio A. and Van der Auweraer H. A model-based synthesis approach for vehicle and aircraft noise. Euronoise Conference, Tampere, Finland, May 2006.17. Janssens K., Vecchio A. and Van der Auweraer H. A model-based synthesis approach for vehicle and aircraft noise. Euronoise Conference, Tampere, Finland, May 2006.18. Janssens K., Van de Ponseele P., Vecchio A. and Van der Auweraer H. A sound design approach for vehicles and aircrafts. Internoise Conference, Honolulu, Hawaii, December 2006.19. Berckmans D., Sas P., Desmet W. and Janssens K. Model-based synthesis of aircraft noise to quantify the subjective human perception. NCTAM Conference, Mons, Belgium, May 2006.20. Crispin Dickson, A QUICKER METHOD OF USING PAIRED COMPARISONS FOR THE SOUND QUALITY EVALUATION, Euronoise 200621. Rudolf Bisping, Variation und Beurteilung tonaler Anteile stationärer Flugzeuggeräusche, DAGA 200622. Leonardo Lecce, Gennaro Scarselli, Francesco Amoroso, Numerical evaluation and experimental comparison of airframe noise for the optimization of next generation aircraft design, ICSV13,

Vienna, 2-6 July 200623. U. Iemma, M. Diez, V. Marchese, "MATCHING THE AIRCRAFT NOISE TO A TARGET SOUND: A NOVEL APPROACH FOR OPTIMAL DESIGN UNDER COMMUNITY NOISE

CONSTRAINTS", ICSV13, 2-6 July, Vienna 24. U. Iemma, M. Diez, "Optimal Conceptual Design of Aircraft Including Community Noise Prediction", 12th AIAA/CEAS Aeroacoustic Conference, Cambridge, Massachussets, 8-10 May 200625. Shafiquzzaman Khan and Crispin Dickson, A comparison study of subjective responses between headphones and loudspeaker reproductions for synthesize aircraft noises, InterNoise 2006,

3rd-6th December 2006, Honolulu26. Rudolf Bisping, Crispin Dickson and Shafiq Khan, PSYCHOMETRIC ANALYSIS OF STATIONARY AIRCRAFT SOUNDS, ICSV 13 Vienna, July 200627. U. Müller, M. Schütte, Sound Engineering for Aircraft (SEFA), first results of listening examinations, InterNoise 2006, 3rd-6th December 2006, Honolulu28. D.Berckmans, K.Janssens, P.Sas, W.Desmet, Model based synthesis of aircraft noise to quantify the subjective human perception, JSV29. R. Scarselli, Airframe Noise Evaluation, AIRTEC 2006, Frankfurt 16 -20 Oct 200630. B. Barbot, C. Lavandier, P. Cheminé, Perceptual space of aircraft sounds, Journal of Applied Acoustics31. U. Iemma, M. Diez, V. Marchese, A Sound-matching-based Approach for Aircraft Noise Annoyance Alleviation via MDO, AIAA conference 200732. Sandrock, S., Schütte, M. & Griefahn, B. 2007, Evaluation modifizierter Flugzeuggeräusche mittels vollständigen Paarvergleiches. In: Gesellschaft für Arbeitswissenschaft (Hrsg.),

Kompetenzentwicklung in realen und virtuellen Arbeitssystemen. Dortmund: GfA Press33. K. Janssens, A. Vecchio and H. Van der Auweraer, Synthesis and sound quality evaluation of exterior and interior aircraft noise, AST 200734. Gennaro Scarselli, Francesco Amoroso and Leonardo Lecce, Karl Janssens and Antonio Vecchio, Numerical simulation, experimental comparison with noise measurements and sound

synthesis of airframe noise, 2007 AIAA Aeroacoustics conference35. "Crispin Dickson, Shafiquzzaman Khan and Rudolf Bisping, Quality of stationary and non-stationary aircraft sounds – theeffect of tonal components and level equalization, ???"

��SEFA

Thank you for your attention!

® Giorgio

sound engineering for aircraft · università degli studi roma tre ... fly-over events were...

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