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Simcenter Qsources Low Frequency Monopole Source 2v9C.docx
Application area
The Simcenter Qsources Low Frequency Monopole Source is a volume displacement source. They are used to
perform calibrated (vibro-) acoustic transfer function measurements. The transfer functions can serve several
purposes:
· Acoustic modal analysis of enclosed cavities
· Coupled structural-acoustic modal analysis
· Quantification of noise from structural excitation (via reciprocity)
· Quantification of acoustic induced vibration of structures
· Quantification of in-situ airborne isolation or airborne transfer
Cross vehicle (vibro-) acoustic transfer function measurement
The Simcenter Qsources Low Frequency Monopole Source can be used on vehicles to investigate the body isolation
between operational sound source locations and the interior target microphones. As the source has similar omni-
directional characteristics as a microphone, the measurement can be done either in a direct or reciprocal way.
A typical instrumentation includes 24 to 60 channel SCADAS frontend, one or two sources and 20-30 microphones.
Typical software includes Simcenter Test.lab Spectral Acquisition.
Acoustic modal analysis passenger car cavities
The Simcenter Qsources Low Frequency Monopole Source is able to excite the acoustic cavity of a passenger car up
to 1 kHz. This makes it an ideal excitation device to derive the complex acoustic modes inside a car. To excite all
modes inside the cavity the minimum number of excitation locations typically exceeds 6. Its small size practically
prevents any influence of the sound field. It can also be positioned in many space constraint areas like the pedal
area or under the seat. A set of sources can also be used as in a Multiple-Input, Multiple-Output configuration(MIMO)
where sources are actuated in parallel with uncorrelated signals.
A typical instrumentation comprises of one or more Simcenter Qsources Low Frequency Monopole Sources, 60-
100 microphones and a Simcenter SCADAS frontend. Typical software includes Simcenter Test.lab Spectral
Acquisition. To emphasize the low frequency output, pink noise can be applied. Monitor the body temperature of
the source when using the source at its limits. Adjust the amplification level such that the electronic protection of
the source is not active.
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