The effect of furniture on room acoustic parameters and its dependence on the sound absorbing properties of the ceiling
(2023) In TVBA-5000 VTAM01 20231Engineering Acoustics
Department of Construction Sciences
- Abstract
- In ordinary public rooms such as classrooms and offices, the base line of acoustical treatment is an absorbent suspended ceiling. Due to the non-uniform distribution of the absorptive ceiling material, the scattering as well as the absorption properties of furniture will have a significant effect on room acoustic parameters such as reverberation time, speech clarity and sound strength. In particular, the absorption of the sound scattered energy will depend on the absorbing efficiency of the suspended ceiling. This effect is not accounted for in classical diffuse field models such as Sabine’s formula which is the norm for the calculation of reverberation time in existing standards. To evaluate the effect of furniture on room acoustic... (More)
- In ordinary public rooms such as classrooms and offices, the base line of acoustical treatment is an absorbent suspended ceiling. Due to the non-uniform distribution of the absorptive ceiling material, the scattering as well as the absorption properties of furniture will have a significant effect on room acoustic parameters such as reverberation time, speech clarity and sound strength. In particular, the absorption of the sound scattered energy will depend on the absorbing efficiency of the suspended ceiling. This effect is not accounted for in classical diffuse field models such as Sabine’s formula which is the norm for the calculation of reverberation time in existing standards. To evaluate the effect of furniture on room acoustic parameters, measurements were conducted in the reverberant room with varying degrees of furnishing for ceiling configurations ranging from highly reflective to highly absorptive. Using Sabine’s formula and the Statistical Energy Analysis model, this dissertation analyzes the scattering and absorptive effects of furniture on reverberation time, speech clarity and sound strength. The absorbing and scattering effects of furniture have been quantified by the parameter equivalent scattering absorption area. How this parameter is affected by the absorptive capacity of the suspended ceiling has also been investigated. It is concluded that both the absorbing and scattering effects of furniture have a significant effect on room acoustic parameters and must be accounted for. Moreover, comparisons of the equivalent scattering absorption area show that the scattering mechanism of furniture dominates at different frequency ranges depending on the ceiling’s absorptive efficiency. Therefore, a novel method is needed for quantification of the absorbing and scattering effects of furniture and how it depends on the absorbing efficiency of the suspended ceiling. This thesis gives some guidance towards such a method. (Less)
- Popular Abstract (Swedish)
- I vanliga rum, som till exempel klassrum och kontor, är grunden för akustisk behandling oftast ett ljudabsorberande undertak. På grund av att större delen av ljudabsorptionen är koncentrerad till en yta kommer den ljudspridande och ljudabsorberande effekten av möbleringen att ha en signifikant inverkan på rumsakustiska parametrar såsom efterklangstid, taltydlighet och ljudstyrka. Speciellt så kommer absorptionen av den ljudspridande energin att påverkas av takets absorptionsförmåga. Denna effekt är inte medtagen i den klassiska diffusfältsteorin som Sabines formel bygger på och som refereras till i många standarder vid beräkning av efterklangstid. För att undersöka möblernas effekt på rumsakustiska parametrar har mätningar utförts i ett... (More)
- I vanliga rum, som till exempel klassrum och kontor, är grunden för akustisk behandling oftast ett ljudabsorberande undertak. På grund av att större delen av ljudabsorptionen är koncentrerad till en yta kommer den ljudspridande och ljudabsorberande effekten av möbleringen att ha en signifikant inverkan på rumsakustiska parametrar såsom efterklangstid, taltydlighet och ljudstyrka. Speciellt så kommer absorptionen av den ljudspridande energin att påverkas av takets absorptionsförmåga. Denna effekt är inte medtagen i den klassiska diffusfältsteorin som Sabines formel bygger på och som refereras till i många standarder vid beräkning av efterklangstid. För att undersöka möblernas effekt på rumsakustiska parametrar har mätningar utförts i ett efterklangsrum med olika möbelkonfigurationer och för olika undertak, från reflekterande till absorberande. Både Sabines formel och en modell som bygger på statistisk energianalys (SEA) har använts för att analysera möblernas effekt på de rumsakustiska parametrarna. Slutsatsen är att både den ljudabsorberande och ljudspridande effekten av möblerna har en signifikant inverkan på de rumsakustiska parametrarna och ska beaktas vid beräkning. Analysen av parametern ekvivalent ljudspridande absorptionsyta visar att den ljudspridande effekten av möblerna dominerar vid olika frekvensområden beroende på takets frekvensberoende absorption. En ny metod behöver utvecklas för kvantifiering av möblernas ljudabsorberande och ljudspridande egenskaper och hur dessa beror av undertakets absorption. Detta examensarbete ger en grund som kan användas för att utveckla en sådan metod. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9131792
- author
- Nguyen, Huong LU
- supervisor
- organization
- alternative title
- Möblers inverkan på rumsakustiska parametrar och hur den varierar med undertakets ljudabsorberande egenskaper
- course
- VTAM01 20231
- year
- 2023
- type
- H3 - Professional qualifications (4 Years - )
- subject
- keywords
- Room acoustics, furniture, Sabine's formula, SEA model, sound absorption, sound scattering, reverberation time, speech clarity, sound strength
- publication/series
- TVBA-5000
- report number
- TVBA-5064
- ISSN
- 0281-8477
- language
- English
- additional info
- Examiner: Professor Kent Persson
- id
- 9131792
- alternative location
- http://www.akustik.lth.se/english/publications/tvba-5000/
- date added to LUP
- 2023-07-03 14:37:48
- date last changed
- 2023-07-03 14:37:48
@misc{9131792,
abstract = {{In ordinary public rooms such as classrooms and offices, the base line of acoustical treatment is an absorbent suspended ceiling. Due to the non-uniform distribution of the absorptive ceiling material, the scattering as well as the absorption properties of furniture will have a significant effect on room acoustic parameters such as reverberation time, speech clarity and sound strength. In particular, the absorption of the sound scattered energy will depend on the absorbing efficiency of the suspended ceiling. This effect is not accounted for in classical diffuse field models such as Sabine’s formula which is the norm for the calculation of reverberation time in existing standards. To evaluate the effect of furniture on room acoustic parameters, measurements were conducted in the reverberant room with varying degrees of furnishing for ceiling configurations ranging from highly reflective to highly absorptive. Using Sabine’s formula and the Statistical Energy Analysis model, this dissertation analyzes the scattering and absorptive effects of furniture on reverberation time, speech clarity and sound strength. The absorbing and scattering effects of furniture have been quantified by the parameter equivalent scattering absorption area. How this parameter is affected by the absorptive capacity of the suspended ceiling has also been investigated. It is concluded that both the absorbing and scattering effects of furniture have a significant effect on room acoustic parameters and must be accounted for. Moreover, comparisons of the equivalent scattering absorption area show that the scattering mechanism of furniture dominates at different frequency ranges depending on the ceiling’s absorptive efficiency. Therefore, a novel method is needed for quantification of the absorbing and scattering effects of furniture and how it depends on the absorbing efficiency of the suspended ceiling. This thesis gives some guidance towards such a method.}},
author = {{Nguyen, Huong}},
issn = {{0281-8477}},
language = {{eng}},
note = {{Student Paper}},
series = {{TVBA-5000}},
title = {{The effect of furniture on room acoustic parameters and its dependence on the sound absorbing properties of the ceiling}},
year = {{2023}},
}