A Study in non-linear seat shaker processors for enhanced integration with full range audio systems
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Sound and vibration (MPSOV), MSc
Publicerad
2024
Författare
Ghijselinck, Lukas
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
This MSc Thesis studies the integration of non-linear seat shaker processors in a
full-range audio system, applied in the car environment. The thesis is conducted on
behalf of the Research and Development Department of Premium Sound Solutions.
The loudspeaker company wants to know more about the scientific implementation
and research behind seat shaker processors in cars. Studies have been done on the
subjective and objective influence of low-frequency sources, namely subwoofers, on
persons. Fewer studies have been done on the haptics and body reaction of lowfrequency
vibrational sound sources in a car environment.
The transmission of low frequencies in a car has a different modal directivity. The
signal affects both the auditory parts with the ear drums as the sensed parts in the
rest of the body. It is found that the auditory spectrum has an influence on the
perceived vibrations.
Therefore a first experiment is done to retrieve subjective data for the influence of
the low-frequency sound source on the body. The data is used to define the shaker
positioning with the corresponding threshold of feeling. Secondly, the vibration acceleration
levels are measured using accelerometers to retrieve the objective data.
Using that objective data, the excited acceleration levels are matched with those of
the subwoofer.
A second listening experiment is done in the form of an A/B listening test. The
interviewees are asked to quantify the difference of the perceived acceleration between
the subwoofer setup and the shaker implementation.
The subwoofer experiment showed that the threshold of sensing the vibrations in the
body is frequency-dependent. It is also found that vibrations are sensed in different
body parts. The excited body parts are also frequency dependent.
The results of the A/B experiment, where both sound pressure levels and acceleration
levels are matched, show that objective measurements and level matching have
the potential to be used as a tuning method. However the quality and implementation of
the used method can be improved
Beskrivning
Ämne/nyckelord
Shakers, Vehicle Seat Vibration, Vehicle Sound Systems, low-frequency sound sources, subwoofer, personal bass