A Study on the Subwoofer Rattle Noise Analysis and System Target Setting

Rattle noise from electrical sound systems is becoming one of the prominent issues for automakers as it directly affects the perception of customers about vehicle quality. Recent times, quality sound system is prerequisite for automotive passenger vehicles. And, in the whole sound systems subwoofer forms dominant part of sound output. However, sub-woofer rattle noise problem sometimes occurs in small and midsize SUV. Generally, sub woofers are located inside rear quarter area (back side of the quarter panel), due to the limitation in the available space. Mainly rattle is noise resulting from physical impact of two parts due to vibrations when relative displacement is bigger than gap of two parts, it occurred in 50-100Hz, which is main excitation range of sub-woofer. In this study, we analyze the sub-woofer structural vibration analysis for five sample vehicles based on the test and correlation. However, the present sub-woofer system model has limitation in determining the level of this rattle noise. Therefore, this paper discusses how to correlate sub-woofer model, frequency, identification of rattle problems and improvements based on the modal correlation. In addition, after the measurement and calculation for the sub-woofer excitation force, the actual load condition has been applied in the model. As a result, the correlation level of sub-woofer system was significantly enhanced compared to the initial model, and it was helpful in identifying rattle problem. Also, the reasonable system target to avoid sub-woofer rattle noise has been considered. In future, this study which can be used to guide design at early stages of vehicle development to avoid rattle problems and over all CAE analyzing process.