The significance of low frequency sounds for perceived sound insulation in lightweight constructionsReport as inadecuate

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2010 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis

Abstract [en] : The acoustical environment in multi-family dwellings is an issue with a steadily increasing importance, and finding a balance between good acoustical privacy and cheap and effective construction methods is one of the biggest challenges for building designers today. The international standard regulates the sound insulation down to 100 Hz, but with the introduction of lightweight building materials as well as advanced home stereo equipment, low frequency sounds has become an increasingly important problem. This has led to an extension of the swedish sound insulation regulations down to 50 Hz. This master thesis aims to investigate if 50 Hz is a sufficiently low limit, or if it is neccessary to extend the limit further down to 20 Hz. This is done in three steps. First, it is investigated whether some objects commonly occuring in multifamily dwellings are able to excite low frequency sounds. Thereafter, the airborne and impact sound insulation in a lightweight construction are measured down to 20 Hz, in order to investigate how the sound insulation at low frequencies differs from the insulation in higher frequencies. Finally, the human perception of low frequency sounds are investigated by performing a listening test where the perceived annoyance level for different sounds commonly occuring in dwellings are analyzed. The investigation shows that there are many commonly occuring sound sources that are able to excite low frequency sounds. Most notably are doors that are being closed, subwoofers, and step sounds. The airborne and impact sound insulation were either the same or worse for frequencies below 50 Hz as the insulation at 50 Hz. The listening test showed that the annoyance level increases with increased sound pressure level. No difference in annoyance could be found between the different sound sources, and neither when comparing full frequency sounds with the same sound with frequencies below 50 Hz removed. Based on the results found in this thesis, and primary those from the listening test, it is not neccessary to extend the sound insulation measurement limit below 50 Hz.

Place, publisher, year, edition, pages: 2010.

Keyword [en] : Technology, Acoustics, low frequency sounds, lightweight constructions

Keyword [sv] : Teknik

Identifiers: URN: urn:nbn:se:ltu:diva-55718ISRN: LTU-EX--10/145--SELocal ID: c8b9c1f3-7721-4043-8e3a-994a3997cb6bOAI: diva2:1029102

Subject / course: Student thesis, at least 30 credits

Educational program: Arenaprogrammes (2002-2014)

Examiners : Ljunggren, Fredrik

Note: Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

Author: Jakobsson, Niklas



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