Authors : Michael L. Hackett

Volume/Issue : Volume 9 - 2024, Issue 8 - August

Google Scholar : https://tinyurl.com/mrz4hppx

Scribd : https://tinyurl.com/4hc93ttu

DOI : https://doi.org/10.38124/ijisrt/IJISRT24AUG1664

Note : A published paper may take 4-5 working days from the publication date to appear in PlumX Metrics, Semantic Scholar, and ResearchGate.

Abstract : This research investigates the acoustic properties of various materials to mitigate sound transmission and enhance acoustic environments, focusing on silk cotton, cotton wool, chipped foam, and open-cell polyurethane foam. The study evaluates these materials for sound absorption and reduction, considering sound frequency and material density. Materials were tested for their sound reduction and absorption coefficients, with silk cotton emerging as the most effective across a broad frequency spectrum, particularly below 200 Hz and above 1000 Hz. The research demonstrated that silk cotton, with its high porosity and fine fibre structure, achieved significant sound reduction even at low densities The findings align with theoretical predictions of resonance frequencies, showing a strong correlation (r2 = 0.9988 for the sound box and r2 = 0.9894 for the sound pipe). Sound intensity and sound pressure levels were measured using a sound level meter, and data analysis was conducted using graphing and calculating software. The researcher employed modified laboratory methods to account for loose materials and equipment limitations, validating the use of theoretical equations to estimate sound absorption and reduction properties The study provides some insights into using fibrous materials like silk cotton for noise reduction and acoustic enhancement. These findings have practical implications for improving sound quality in various environments, such as schools, studios, and public spaces, contributing to noise reduction strategies and enhancing auditory experiences.

Keywords : Attenuation, Box Acoustics, Decibel, Impedance Mismatch, Pipe Acoustics, Resonance, Silk Cotton (Kapok), Sound Absorption, Sound Level, Sound Reduction, Sound Transmission.

References :

1. Acoustiblok. (2023, May 1). Sound absorption principles explained. Acoustiblok UK Ltd/Thermablok Aerogel Ltd. https://www.acoustiblok.co.uk/sound-absorption-principles-explained/
2. Berg, R. E. (2024, May 20). The Helmholtz resonator. Encyclopedia Britannica. https://www.britannica.com/science/sound-physics/The-Helmholtz-resonator
3. Berg, R. E. (2024, May 20). Impedance. Encyclopedia Britannica. https://www.britannica.com/science/sound-physics/Impedance
4. Blythe, S. G. (2017). Attention, Balance and Coordination: The A.B.C. of Learning Success. John Wiley & Sons Ltd. https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781119164746.app2
5. Britannica, The Editors of Encyclopaedia. (2024, January 15). Kapok. Encyclopedia Britannica. https://www.britannica.com/topic/kapok
6. Britannica, The Editors of Encyclopaedia. (2024, April 5). Wallace Clement Sabine. Encyclopedia Britannica. https://www.britannica.com/biography/Wallace-Clement-Ware-Sabine
7. Chin, P. (2016, March 13). Silk Cotton Tree. Stabroek News. https://www.stabroeknews.com/2016/03/13/features/silk-cotton-tree/Diamant, R.M.E. (1986). Thermal and Acoustic Insulation. Buttersworth.
8. Diehl, G.M. (1973). Machinery Acoustics. John Wiley & Sons.
9. Ford, R.D. (1970). Introduction to Acoustics. Elsevier Publishing Company Limited.
10. Halliday, D., Resnick, R. & Walker, J. (1993). Fundamentals of Physics (4^th Ed). John Wiley & Sons, Inc.
11. IAC Sound Absorption Systems. (2002, April). Acoustical conditioning of high noise level areas with reverberation control systems. www.iachk.com/ProductPages/SoundAbsorptionSystems.html
12. Jessurun, K. (2024, April 1). Ceiba pentandra – kapok tree. Tropilab Inc. https://tropilab.com/ceiba-pen.html
13. Khroodsma, D. (2005). The Singing Life of Birds. Houghton Mifflin
14. Mackenzie, G.W. (1964). Acoustics. Focal Press.
15. Marsh, A.J. (2006). Office Acoustics. Natural Frequency Journal. https://web.archive.org/web/20180312221156/http://naturalfrequency.com/articles/officeacoustics
16. Morse, P.M. & Ingard, K. U. (1986). Theoretical Acoustics. Princeton University Press
17. Nathanson, J. A., & Berg, R. E. (2024, June 5). Noise pollution. Encyclopedia Britannica. https://www.britannica.com/science/noise-pollution
18. Norlite Agg. (2002, April). Sound Transmission Properties. https://www.norliteagg.com/sites/default/files/imce_images/norlite_sound_transmission.pdf.  
19. Pierce, A.D. (1994). Acoustics: An Introduction to its Physical Principles and Applications. Acoustical Society of America.
20. Randall, R.H. (1951). An Introduction to Acoustics. Addison-Wesley Publishing Company, Inc.
21. Richardson, E.G. (ed.) (1962). Technical Aspects of Sound. Elsevier Publishing Company.
22. Souza, E. (2021, May 9). Keys To Improve Architectural Acoustics: Sound Absorption and Diffusion. Arch Daily. https://www.archdaily.com/912806/understanding-sound-absorption-and-diffusion-in-architectural-projects
23. The Physics Classroom. (2022). Formation of Standing Waves. https://www.physicsclassroom.com/Class/waves/u10l4b.cfm
24. Tyler, F. (1981). A Laboratory Manual of Physics 5^th Ed. Edward Arnold (Publishers) Ltd.
25. Yarwood, T. M. (1953). Acoustics- A Textbook for Physics and Engineering Students. Macmillan & Co., Ltd.