Scanning Vibrometer System (SCN)
- Measure geometry and mechanical vibration of the transducer
- Visualize the vibration behavior
- Show contribution to sound pressure output
- Predict directivity pattern
- Separate radial and circular modes
- Analyze actively radiating cone regions
- Detect loudspeaker defects
The SCN Analysis Software performs visualization, animation and analysis of the mechanical vibration using the scanned data which is provided by the vibrometer. The sound pressure output at any point in the half-space sound field and the polar radiation characteristic are predicted by using mechanical data. Novel decomposition techniques show radial and circular modes and vibration components related to the SPL output. It is the target of the analysis to provide a better understanding of the interaction between vibration and radiation. Deepened analytics can be provided by optional modules for modal analysis of rocking modes and higher order modes.
Midrange driver with special honeycomb cone structure
At 6kHz there is a significant dip in the on-axis sound pressure response. The inner and outer cone region vibrate in phase opposition and the resulting volume flows cancel each other out. The reason is a good bending moment propagation between the inner and outer cone due to the stiff honeycomb membrane, which leads to this distinct vibration mode.
Viewer Software and Examples
The SCN Vibrometer comprises the following components
• 3D Scanner (3 actuators move the laser in polar coordinates)
• Motor Control Hardware
• SCN Analysis Software
Other components required for SCN
• Laser LK-H052
• Klippel Analyzer 3
• Transfer Function Module (TRF):
Measurement of transfer function and harmonic distortion
• Power amplifier
It is recommended to use coating spray for transparent and shiny diaphragms. More information.
The figure above illustrates the vibration and radiation analysis based on distributed mechanical loudspeaker parameters measured by laser scanning to select the optimal transducer and to perform loudspeaker diagnostics.
• AN 30 Scanning Rectangular Speakers
• AN 31 Cone Vibration and Radiation Diagnostics
• AN 32 Effective Radiation Area
• AN 55 FEA_BEA Interface for SCN
• Example files for AN 55
• AN 66 FEA2SCN Interpolation for SCN
• AN 68 Importing Polytec data into SCN