Methods for product sound design: a correlation between annoyance and sound quality of noise emitted by household appliance

Abstract

The sound quality analysis, used as a tool for the product design, has been defined and described in the literature and the characteristics describing the type of sound have been identified. However it is often not known how the subjective assessments and the human factor are taken into account in the procedure governing the studies of sound quality. Today making a product as quiet as possible is one of the most captivating challenge for the industrial sector, especially if it is for a household appliance. This case study show how the consumer perception of product sound quality is a fundamental variable to define the sound character. The classification of sound quality is based on the correlation between an objective measurement and the subjective judgment result. Psychoacoustic metrics like Loudness, Sharpness and Roughness, and the combinations of them into more sophisticated models, like annoyance, pleasantness and powerfulness are commonly used for analysis and prediction of product sound quality. However, some problems arise when the sounds are analyzed by different consumers. It is assumed that the reason for this is the human not ability to understand the difference between noise and annoyance and to focus consciously or unconsciously on the sound emitted by the appliance. For this reason the aim of this work is to validate a method to calculate a sound quality index applicable to the sounds produced by five kitchen hoods in a real installation condition.