Sound Quality Evaluation for the Vehicle HVAC System After Active Noise Control

Abstract

The reduction of the Vehicle interior noise has been the main interest of NVH engineers. The driver’s perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. In previous study, we have developed to verify identification of source for the vehicle HVAC system through multiple-dimensional spectral analysis. Also we carried out objective assessments on the vehicle HVAC noises and subjective assessments have been already performed with 30 subjects. In this study, the linear regression models were obtained for the subjective evaluation and the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Appropriation of regression model is necessary to R2 value and F-value. And testing for regression model is necessary to Independence, Homoscedesticity and Normality. To enhance sound quality, we applied active noise control (ANC) which is effective in the low-frequency bandwidth. Primary noise of the HVAC system is less than 500Hz. As a result of ANC application, sound quality is improved by more quiet, powerful, expensive, smooth.

Acoustic Sensing and Noise Identification of a Heating, Ventilation and Air Conditioning Unit: Industrial Case Study

“…In order to reduce the level of the noise, there are some techniques that can be used for post-production noise control. These techniques include active noise control reported in [11,15], and passive noise control using synthetic sound absorbing materials such as micro-perforates [6,7], fiberglass, glass wool and polypropylene [16]. These passive techniques help to reach up to 6-10 dB noise reduction and work best at frequencies above ≈500 Hz.…”

Formulation of noise isolation index for evaluating the interior acoustics level in vehicle cabin

“…[5][6][7] In this regard, over the past decades, multiple studies have been done purposely to investigate and evaluate the level of comfort inside the car cabin and to estimate the effects of exposed noise vibration on the driver health and concentration. [7][8][9][10][11] Studying the acoustical comfort in vehicles is essential task in front of acoustics engineers when designing and manufacturing a vehicle. This is due to the recent ever increasing demands for suppressing and reducing undesirable noise in the vehicle interior cabin.…”