Qlmf Low Mid Frequency Volume Source


The Simcenter Qsources hardware lowmid frequency source is used for producing high noise levels, more than sufficient for the excitation of complete vehicles. The integrated volume acceleration sensor gives realtime feedback of the emitted source strength and can be used as a reference for frequency response functions (FRFs) measurements without any postprocessing. The low-mid frequency source is designed to be used in the 10 to 1,000 hertz (Hz) frequency band an important frequency band in vehicle development. This source is typically used for transfer path analysis (TPA) of structure-borne or airborne noise and cabin vibro-acoustic modal analysis. Because most applications are for seat positions, the device is optimized for quick positioning on a seat with the acoustic center at ear location. This is in compliance with ISO 5128. For linear systems, the reciprocity principle is applicable. As a vehicle can be seen as a linear system in typical cases, the input and output of the system can be switched. This allows you to introduce acoustic energy at ear location and measure acceleration at many operational force input points, such as body interface locations for the suspension, exhaust and engine. This will result in a shorter FRF acquisition time as it is not necessary to excite the system at every force input location with a shaker.


  • Volume acceleration sound source for scaled acoustic driven frequency response functions
  • Driver and integrated sensor for a source level signal with long-time stable calibration 
  • High sound pressure level in contained spaces, between 10 and 1000 Hz
  • Specifically suitable for reciprocity based vibro-acoustic frequency response function measurements in aircraft, cars, trains, trucks, etc.
  • Provides a point sources at ear location and human body diffraction, fast positioning on a seat 
  • Built-in overload protections