Sources | VVS

Low Frequency Volume Velocity Source

lowfrequencymonopole4 Click to enlarge

The low frequency monopole of Microflown Technologies is an omni-directional volume velocity sound source. The sound source has a particle velocity reference sensor to measure accurate the output of the source. The frequency range covered by this source is from 30Hz up to 300Hz. The upper frequency is limited by the source diameter. If higher frequencies are required, a mid-high frequency monopole is also developed covering a bandwidth of 100Hz up to 7kHz. The sound power output of a monopole source is proportional with the frequency squared. The sound pressure at one meter is therefore low at lower frequencies. To be able to reach relative high sound pressure levels at low frequencies with an acceptable source velocity level one needs to increase the source diameter. For an omni-directional behavior however, the diameter should be small compared to the wavelength. The low frequency monopole has a source diameter of 160mm.

The low frequency monopole is delivered as complete  system including needed accessories such as amplifier, cabling etc.





  • Panel Noise Contribution Analysis
  • SMT Substitution Monopole Technique
  • In-situ transmission loss measurements
  • General airborne and structure borne transfer functions
  • Scan & Paint TPA


  • Cabin Interior Panel Noise Contribution Analysis
  • In-situ transmission loss measurements