Application Note: Transfer Path Analysis

What kind of a noise is made when the surface of a component vibrates? What path does the noise take to your ear? What component vibration is most undesirable? These are the questions that employees at Polytec and HEAD acoustics are currently trying to solve within the framework of a joint project.

Acoustics are increasingly important in product design. The focus is on how and where are undesired noises generated and at which point or location can countermeasures be taken to eliminate or attenuate the offending noise. Knowing just the vibration characteristics of a component is not enough to describe the acoustical situation sufficiently - the degree of the sound projection, the transmission of the noise to your ear (the socalled transfer function for airborne sound) and the structure of the noise (important for the psycho- acoustic effect on a person) must be considered. Consequently, even though a component's physical vibration might be reduced, the noise that has impact on the listener may not be audibly reduced. Thus, the questions persist: Which vibrations are generating the offending noise? At what location should countermeasures be applied?

A joint project between Polytec and HEAD acoustics aims to answer these questions and make a connection between vibration analysis on the one hand and the noise generated on the other. Polytec has expertise in matters of laser vibrometry and vibration analysis. HEAD acoustics has expertise with regards to auralization of sound sources. The degree of sound radiaition efficiency, of the two companies working together will be a development tool which can be applied to aural acoustic problems in the future.

SOURCE: Polytec