Test room whose surfaces absorb essentially all of the incident sound energy over the frequency range of interest, thereby affording nearly free-field conditions over the measurement surface. A recording device that simulates the dynamics of human hearing, as well as the influence of the human body on the acoustic environment inside a vehicle. An analytical technique that quantifies the distribution of sound energy within the audible frequency spectrum, enabling the tonal characteristics of problem noise to be identified. A test chamber with sound absorbing materials on the walls and ceiling, but not the floor. This environment is ideal for recording brake system sounds for psycho-acoustic analysis using a binaural recording head in a vehicle cabin, since the environment created is similar to that of a vehicle cruising on a paved road.
Results reveal specific frequencies of various brake system components, or portions thereof.
A brake system testing protocol developed by TRW Automotive to quantitatively categorize a system's NVH performance. It's used as the basis of the European Matrix standard. A sound quality rating value based on measurable sound attributes, numerically weighted based on subjective psycho-acoustic responses. This measures the quantitative aspects of sound, as well as the qualitative characteristics. The goal is to provide repeatable measures of sound qualities consumers consider pleasing and not so pleasing.