Loudness equalization of interactive signal sounds in car compartment
Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
Modern signal sounds in cars are complex, varied and tonal making them hard to tune (set the play back level) between the signals so they are perceived as equally loud. An information signal should be perceived as equally loud as another information signal, even though they might be totally different in length, frequency content, etc. Loudness is defined as the perceived sound level rated between quiet to loud. Measurements and trials with loudness models are well known for steady tones but rather unexplored when it comes to short, transient sounds, such as signals in the car. Previous trial av Volvo Car Corporation have included dB(A)-weighting and ISO15006:2011 with unsatisfactory result. The aim was to evaluate if a loudness over time model could be used to improve the tuning process in the car compartment. Eight signal sounds, divided into different pairs and anchors from a Volvo XC90 was used for the study. The pairs were loudness equalized with two different methods (Filter/ISO532B and FFT/ANSI S3.4-2007) in Head Acoustics ArtemiS. A listening test was conducted (at Volvo Car Corporation) where the subjects compared the perceived loudness for each pair in an AB5 test. All sounds were tested with and without a masking sound from tyre noise. The result from the listening test show that the Filter/ISO532B in most cases work better than the FFT/ANSI S3.4-2007 for loudness equalization. As the theory suggest the temporal masking effects give a smaller range of loudness when a masking noise is present. When noise is not present the methods are equally good with a small advantage for the Filter/ISO532B method. In the environment of a car signal sounds are rarely played in total silence, suggesting that the Filter/ISO532B method is preferred as an indicator for setting sound levels in the tuning process.
Place, publisher, year, edition, pages
2016. , 27 p.
Technology, Loudness over time, loudness equalization, signal sounds, car compartment, audio design, loudness
IdentifiersURN: urn:nbn:se:ltu:diva-58596Local ID: f2dfd8c3-fd9f-45d1-9fba-b7dfd309b2d9OAI: oai:DiVA.org:ltu-58596DiVA: diva2:1031984
Subject / course
Student thesis, at least 15 credits
Industrial Design Engineering, bachelor's level
Johnsson, RogerHagman, Fredrik
Validerat; 20160711 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved