Engine Sound Weighting using a Psychoacoustic Criterion based on Auralized Numerical Simulations
Regular paper
Otto von Guericke University Magdeburg
Wednesday 3 june, 2015, 10:40 - 11:00
0.7 Lisbon (47)
Abstract:
Today the product quality of automobiles is increasingly influenced by the noise comfort of the acoustic perception of the customers. Consequently, a brand-specific design of sounds is applied by the car manufactures, which offers a growing potential for qualitative differentiation. One major aspect of such a qualitative differentiation is the sound quality caused by the emission noise of a combustion engine. The primary objective of this paper is to evaluate the sound of an engine focusing on its auditory sensation on sound quality. Instead of measuring the acoustic behavior of a real prototype an overall numerical model of the engine is applied to receive audible signals of the engine. These audible signals are used to carry out paired comparison listening tests, which finally lead to an interval scaled ranking of the stimuli. A psychoacoustic model is derived, based on the highest correlation to describe the subjective evaluation of engine sounds. This psychoacoustic model is a function, which consists of a weighted combination of significant, classical psychoacoustic parameters like loudness and sharpness. The resulting psychoacoustic model describes and predicts the auditory sensation of sound quality on the basis of signal processing of the time signal only - without any further auralization or hearing test. The advantage of the presented concept is that the perceived quality of an engine encapsulation can be optimized before a real prototype is built, because only simulation results are needed as input for the psychoacoustic model. In the paper at hand this approach is applied to evaluate different types of encapsulations of engines, which can reduce the emitted noise significantly. The example shows that the human, auditory sensation should be used during the design process to evaluate the sound quality, not just a physical parameter like the pressure level.