AES E-Library

AES E-Library

Measurements of Operating Modes on a Loudspeaker Cabinet

Document Thumbnail

Modal analysis is a powerful tool which can be used to create a dynamic model of a structure, but for some problems the application of a dynamic model is not feasible. In some applications the operating dynamic-excitation forces cannot be determined, and in others only a few of the modes may be excited in normal operation. For such cases, a complete dynamic model is not needed. This paper presents an alternative technique, the measurement of operating modes (OM). The operating mode shapes represent a set of shapes into which the forced vibrations can be decomposed, one shape for each significant modal frequency. The visualized shapes and understanding of the dynamic behavior of a structure and hence how improvements may be made to the design for optimum performance. The technique was applied in the development of a prototype loudspeaker cabinet. To simulate normal operation, the loudspeaker was driven using weighted random noise with shaped auto-spectrum equivalent to a typical music spectrum. The operating modes are identified from complex transmissibility functions measured between a reference accelerometer and a roving accelerometer on the cabinet. Further qualitative and quantitative applications of measured operating modes are also suggested.

AES Convention: Paper Number:
Publication Date:

Click to purchase paper as a non-member or login as an AES member. If your company or school subscribes to the E-Library then switch to the institutional version. If you are not an AES member and would like to subscribe to the E-Library then Join the AES!

This paper costs $33 for non-members and is free for AES members and E-Library subscribers.

Learn more about the AES E-Library

E-Library Location:

Start a discussion about this paper!

AES - Audio Engineering Society