Lecture-02-20-08 - MECH 668 Vehicle Noise, Vibration and...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
MECH 668 Vehicle Noise, Vibration and Harshness (NVH) Vehicle Sound Quality Applications Winter 2008
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Sound Quality Issues Component noise Exterior noise Interior noise Vehicle Sound Quality Concerns
Background image of page 2
3 Sound Quality Analysis Steps ± Conduct single mic or binaural head measurements ± Perform subjective jury evaluation testing ± Analyze objective measures and compute metrics ± Correlate metrics to the physical parameters ± Identify design improvement ± Perform verification testing
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 Measurements ± Testing Environment 9 Operating field testing (on-road, test track) 9 Lab testing (i.e. semi-anechoic room, chassis roll dyno) ± Sampling rate needs to be at least 44 kHz to cover full range of hearing frequencies. With 44 kHz sampling, we get at least 20 kHz usable frequencies. Front mic Binaural Head Example of a lab setup to measure interior sound response, using single-mic and binaural head (dual-mic), due to applied harmonic force at the engine mounts
Background image of page 4
5 Subjective Jury Evaluation ± Jury selection – Evaluators should represent a broad range of of consumers who will likely ride on the vehicle ± Testing procedures – driven by goals and purpose of the test ± Testing environment – Testing can be performed in actual or simulated environment ± Rating scales – verbal and numerical scales can be used ± Non-acoustic factors – Socio-cultural and economic factor may influence the outcome ± Jury elimination process – Individual response may be eliminated if it is completely inconsistent with the jury group. ± Jury comment – may be used to determine the underlying reasons for preferences
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 Jury Testing Procedures ± Magnitude estimation – jury members rate sounds using numerical values of their choice ± Fixed interval method - jury members rate sounds using a definitive scale given in the test ± Paired comparison - jury members rate sounds by judging a pair of sounds using a relative scale
Background image of page 6
Image of page 7
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/13/2010 for the course MECH 668 taught by Professor Lim during the Winter '08 term at University of Cincinnati.

Page1 / 22

Lecture-02-20-08 - MECH 668 Vehicle Noise, Vibration and...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online