Wideband Volume Velocity Sources

Volume velocity sources (VVS) are used as ‘acoustical shakers’ to measure acoustic frequency response functions – sound pressure per unit volume velocity – typically in connection with noise source contribution analysis. Uniquely, HBK volume velocity sources use a special dual-microphone probe to measure accurate volume velocity directly in real time.

HBK 4250 wideband volume velocity sources cover the full acoustic frequency range with two powerful drivers to maximize signal-to-noise in real-world conditions, and three probes providing calibrated volume velocity in the low-, mid-
and high-frequency ranges.

The driver units are designed to handle real-world measurement scenarios with high transmission loss or background noise that cannot be reduced, such as in outdoor situations.
Built-in overload protection ensures robust performance.

When used with BK Connect® software, volume velocity is monitored and measured in real time. Vibro-acoustic frequency response functions – sound pressure per unit force – can be measured using the reciprocal method and acceleration per unit volume acceleration.

 

CAPABILITIES

• Wideband omnidirectional acoustic radiation for assessment of both airborne and structure-borne generated phenomena
• Accurate in situ measurement of output volume velocity using a pair of low-noise, ¼-inch microphones
• Dual-microphone design minimizes near-field effects of the test object for optimum measurement accuracy
• High-power output for measurement on vehicles with high transmission loss or when background noise conditions are sub-optimal
• Measurement of frequency response functions at vehicle source systems (engine bay, tyres etc.) with the use of a low-emission, 3-metre hose
• Quick-release coupling system for switching probes or hose-probe assemblies on the driver
• Microphones with CCLD and TEDS for quick setup
• Built-in overload protection circuit
• Can be used with BK Connect software for real-time volume velocity measurements:
  • Use VVS Measurements Type 8442 for frequency response measurements related to a pass-by source path contribution model
  • Use Data Processing Type 8403 for general NVH measurements
    
    

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Related links:

• User Manual for HBK 4250