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Scanning mechanical vibration

Characteristics:

KLIPPEL R&D System
Complex transfer function Hx(r, f) at point r on the radiator’s surfaceTRF, SCN
Magnitude and phase plotSCN
Animated vibration patternSCN
Distributed mechanical parameters SCN

The complex transfer function between electrical input and mechanical vibration measured at multiple points r with sufficient spatial resolution on the surface of the radiator may be considered as distributed parameters describing the vibration behaviour of the transducer in the small signal domain. The data can be represented as magnitude and phase response at a particular point, as a distribution of magnitude and phase over the surface, and as a 2D or 3D animation where the vibration is superimposed with the geometry of the radiator.

KLIPPEL R&D SYSTEM (development)

Module

Comment

Transfer Function Module (TRF)

Using a sweep with amplitude shaping (emphasis by 10 dB/octave to higher frequencies), TRF measures the displacement transfer function Hx(f) at higher frequencies (25 kHz) with sufficient SNR.

Scanning Vibrometer (SCN)

SCN uses TRF, DA hardware, laser and additional control robotics (two linear actuators and a turntable) to scan the mechanical vibration and geometry.

Example:

The figure above shows different ways how to visualize the transfer function describing the vibration of the scanned surface.
The figure above shows different ways how to visualize the transfer function describing the vibration of the scanned surface.

Templates of KLIPPEL products

Name of the Template

Application

TRF Scanning Cone Vibration

Manual scanning of cone vibration using a laser sensor with high cut-off frequency (>15 kHz)

Standards:

  • AES2-1984 AES Recommended practice Specification of Loudspeaker Components Used in Professional Audio and Sound Reinforcement
  • IEC Standard IEC 60268-5 Sound System Equipment, Part 5: Loudspeakers




Papers and Preprints:

W. Klippel, et al., “Distributed Mechanical Parameters of Loudspeakers Part 1: Measurement,” J. of Audio Eng. Soc. 57, No. 9, pp. 500-511 (2009 Sept.).

W. Klippel, et al., “Distributed Mechanical Parameters of Loudspeakers Part 2: Diagnostics,” J. of Audio Eng. Soc. 57, No. 9, pp. 696-708 (2009 Sept.).

F. J. M. Frankort, “Vibration Patterns and Radiation Behavior of Loudspeaker Cones,” J. of Audio Eng. Soc., Volume 26, No. 9, pp. 609-622 (September 1978).

J. R. Wright, “Automatic Vibration Analysis by Laser Interferometry,” presented at the 88th Convention of the Audio Eng. Soc., Preprint 2889, (March 1990).

C. Struck, “Analysis of the Nonrigid Behavior of a Loudspeaker Diaphragm using Modal Analysis,” presented at 86th convention of Audio Eng. Soc., Hamburg, Preprint 2779 (1989).

P. J. Anthony, et al., “Finite-Element Analysis in the Design of High-Quality Loudspeakers,” presented at the 108th Convention of the Audio Eng. Soc., February 2000, Preprint 5162.

M. Karjalainen, et al., “Comparison of Numerical Simulation Models and Measured Low-Frequency Behavior of a Loudspeaker,” presented at the 104th Convention of the Audio Eng. Soc., May 1998, Preprint 4722.

J. Wright, “Finite Element Analysis as a Loudspeaker Design Tool,” Paper MAL-11; Conference: AES UK Conference: Microphones & Loudspeakers, The Ins & Outs of Audio (MAL), March 1998.

A. Bright, “Vibration Behaviour of Single-Suspension Electrodynamic Loudspeakers,” presented at the 109th Convention of the Audio Eng. Soc., (September 2000), Preprint 5213.