Thesis

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Investigation of Air Noise in Micro Loud-Speaker Systems

Authors Berghold, P.
Year 2021
Thesis Type Master's thesis
Topic Audio Signal Processing
Abstract Micro-loudspeaker systems suffer from the growing requirement for higher sound pressures levels, while their membrane area should decrease. Therefore, an exceeding membrane excursion, especially at low frequencies, is required. These excursions are physically related to the introduced air velocity in front of the membrane. The resulting high velocity is the cause of unwanted noise in sound ports, due to turbulences and vortex shedding in boundary layers and port edges. Standard parameters like the total harmonic distortion and compression fail to give a clear understanding if port noise is present or not. This work has the aim to define proper measurement conditions and identify a fingerprint/indicator for port noise caused in micro speaker systems. The findings will be related to the research done on port noise in bass reflex systems and validated with CFD simulations.
Supervisors Sontacchi, A.