4295 OmniSource with 4299 Volume Velocity Adaptor

Omnidirectional Volume Velocity Source based on OmniSource Type 4295

OmniSource covers the most important frequency range for the automotive industry, that is, from 50 Hz to around 6 kHz. Volume Velocity Sources are used as "acoustical shakers" to measure acoustic transfer functions, typically in connection with noise source contribution analysis (e.g.,Transfer Path Analysis). Transfer function measurements require accurate measurement of the applied excitation signal.

Therefore, an adaptor, Volume Velocity Adaptor Type 4299, has been to be added at the acoustic output of Omnisource to measure the output Volume Velocity - just as a force transducer is required on a shaker when used for transfer function measurements. The adaptor contains two phase-matched microphones, which can measure:

• Output Volume Velocity
• Frequency Response Functions (FRFs) from output Volume Velocity to a set of measured responses (typically Sound Pressure and/or Vibration Velocity)

The major strong points of the new Volume Velocity Source are:

• Coverage of the entire frequency range of primary interest
• Very accurate measurement of the output Volume Velocity, also under changing load conditions (e.g., in enclosed spaces)
• High degree of omnidirectivity over a wide frequency range