Sound Quality Improvement of Car Interior Noise Through the Change of Order Spectrum

Sung-Hwan† Shin; Takeo* Hashimoto

doi:10.7776/ASK.2013.32.4.329

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2013 Vol.32, Issue 4 Preview Page Next Page

Sound Quality Improvement of Car Interior Noise Through the Change of Order Spectrum 차수 스펙트럼 변화를 통한 차실내부 음질 향상

31 July 2013. pp. 329-334

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Abstract

Order spectrum analysis is widely used to grasp the features of noises due to powertrain system including engine and intake/exhaust system. It is known from many previous researches that order components related to the first and second firing frequencies of engine considerably affect the noise of car interior. The purpose of this paper is to find out the difference in sound quality: Pleasantness of car interior noise according to the change of its order spectrum. For this, car interior noises of 6-cylinder and 4-cylinder engines are recorded and their order spectrum levels are modified by applying adaptive digital filters. After subjective listening test employing paired comparison method is conducted, it is investigated that the level change of half-order components is a noticeable factor to improve Pleasantness of the car interior noises whereas level decrease of firing order does not always give the positive effect on its sound quality.

Keywords

Car interior noise

Sound quality

Order spectrum

Pleasantness

Paired comparison method

자동차 엔진을 포함한 구동계 및 흡배기계 소음의 특징은 차수 스펙트럼 (order spectrum) 분석으로 파악할 수 있다. 기존의 선행 연구에서는 엔진의 1차 및 2차 점화주파수 (firing frequency)와 관련된 차수성분이 차실내부 소음에 주요한 영향을 미치는 것으로 알려져 있다. 본 연구에서는 차수스펙트럼의 변환에 따른 차실내부 소음의 음질 (쾌적감) 차이를 파악하고자 한다. 이를 위하여 6실린더 및 4실린더 가솔린 엔진을 가진 승용차의 차실 내부 소음을 측정하고, 이 소음에 적응형 디지털 필터 (adaptive digital filter)를 적용하여 차수레벨을 가감하는 방법으로 수정한다. 쌍비교법을 이용한 청음실험을 통하여 원음 및 편집음의 음질 정도를 평가하고, 음질 향상을 위한 차수스펙트럼 변화 방향을 제시한다. 결과적으로 반차수 (half-order) 성분의 차수레벨 감소가 차실내부 소음의 쾌적감 향상에 영향을 주는 반면, 점화차수 레벨의 감소가 항상 음질에 긍정적인 영향을 주는 것은 아님을 파악하였다.

키워드

차실 소음

음질

차수스펙트럼

쾌적감

쌍비교법

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Information

Publisher :The Acoustical Society of Korea
Publisher(Ko) :한국음향학회
Journal Title :The Journal of the Acoustical Society of Korea
Journal Title(Ko) :한국음향학회지
Volume : 32
No :4
Pages :329-334
Received Date : 2013-04-11
Accepted Date : 2013-05-08
DOI :https://doi.org/10.7776/ASK.2013.32.4.329

The Journal of the Acoustical Society of KoreaISSN:1225-4428(Print) 2287-3775(Online)한국음향학회

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