Does it matter whether single-number values of sound reduction indices are evaluated from third-octave band values or from octave band values?

2012 ◽  
Vol 98 (2) ◽  
pp. 354-360 ◽  
Author(s):  
Werner Scholl ◽  
Volker Wittstock
Keyword(s):  
Octave Band ◽  
Single Number ◽  
Sound Reduction

scholarly journals IMPLEMENTATION OF LABORATORY MEASUREMENT OF AIRBORNE SOUND INSULATION BASED ON ISO AND ASTM STANDARDS IN NATIONAL STANDARDIZATION AGENCY OF INDONESIA (BSN)

2021 ◽  
Vol 23 (1) ◽  
pp. 77
Author(s):  
Bondan Dwisetyo ◽  
Maharani Ratna Palupi ◽  
Fajar Budi Utomo ◽  
Chery Chaen Putri ◽  
Dodi Rusjadi ◽  
...  
Keyword(s):  
Transmission Loss ◽  
Laboratory Measurement ◽  
Sound Insulation ◽  
Reference Curve ◽  
Airborne Sound ◽  
Significant Difference ◽  
Single Number ◽  
Sound Reduction ◽  
Reduction Index

<p>The implementation of laboratory measurement of airborne sound insulation based on ISO and ASTM standards was carried out at SNSU BSN. The aim of this work to realize the measurement of airborne sound insulation for several sample tests, where the procedure of the test is performed according to the updated standard ISO 10140 and ASTM E90. Besides, the single number rating also is determined based on ISO 717-1 and ASTM E413. This measurement has been conducted in the two reverberation rooms using pressure method consist of measuring the sound pressure level, measuring the reverberation time, obtaining the sound reduction index (R) or sound transmission loss (STL), and determination of a single-number ratings of the samples test. From the results, some parameter requirements such as the frequency range and the rounding procedure of R or STL influence the measurement result slightly. Subsequently, the significant difference is obtained for the determination of single number rating in the shifting procedure of the reference curve.</p>

scholarly journals Review of acoustic comfort evaluation in dwellings: Part III—airborne sound data associated with subjective responses in laboratory tests

2018 ◽  
Vol 25 (4) ◽  
pp. 289-305 ◽  
Author(s):  
Nikolaos-Georgios Vardaxis ◽  
Delphine Bard
Keyword(s):  
Human Perception ◽  
Low Noise ◽  
Subjective Response ◽  
Low Frequencies ◽  
Subjective Data ◽  
Speech Stimuli ◽  
Airborne Sound ◽  
Acoustic Comfort ◽  
Single Number ◽  
Sound Reduction

Acoustic comfort has been used in engineering to refer to conditions of low noise levels or annoyance, while current standardized methods for airborne and impact sound reduction are used to assess acoustic comfort in dwellings. However, the results and descriptors acquired from acoustic measurements do not represent the human perception of sound or comfort levels. This article is a review of laboratory studies concerning airborne sound in dwellings. Specifically, this review presents studies that approach acoustic comfort via the association of objective and subjective data in laboratory listening tests, combining airborne sound acoustic data, and subjective ratings. The presented studies are tabulated and evaluated using Bradford Hill’s criteria. Many of them attempt to predict subjective noise annoyance and find the best single number quantity for that reason. The results indicate that subjective response to airborne sound is complicated and varies according to different sound stimuli. It can be associated sufficiently with airborne sound in general but different descriptors relate best to music sounds or speech stimuli. The inclusion of low frequencies down to 50 Hz in the measurements seems to weaken the association of self-reported responses to airborne sound types except for the cases of music stimuli.

A Comparative Study of Sound Transmission Loss Provided by Glass, Acrylic and Polycarbonate

2013 ◽  
Vol 60 (1) ◽  
Author(s):  
Elwaleed Awad Khidir ◽  
Zambri Harun ◽  
Mohd Jailani Mohd Nor ◽  
Muhamad Razi
Keyword(s):  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Insulation ◽  
Sound Transmission Loss ◽  
Material Density ◽  
Airborne Sound ◽  
Single Number ◽  
Reverberation Chambers ◽  
Sound Reduction ◽  
Reduction Index

This article presents an assessment for the airborne sound insulation provided by single glazed panels. The glazed panels were glass, acrylic and polycarbonate with a thickness of 4 mm. The experiments were conducted in a transmission loss facility consisting of semi anechoic and reverberation chambers. The panels were subjected to airborne sound and the data collected. Glass, acrylic and polycarbonate panel absorb noise most effectively above 500 Hz with the absorption peaks at 1000 Hz. The single number sound reduction index (RW) for glass, polycarbonate and acrylic were 41 dB, 38 dB and 37 dB, respectively. This could be attributed mainly to the material density which is higher for the glass. Keywords: Sound transmission loss; glazing; insulation; weighted index

Effects of Wall-to-Wall Supported Ceilings on Impact Sound Insulation for Use in Residential Buildings

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 587
Author(s):  
Sin-Tae Kim ◽  
Hyun-Min Cho ◽  
Myung-Jun Kim
Keyword(s):  
Residential Buildings ◽  
Sound Insulation ◽  
Concrete Slabs ◽  
The Past ◽  
Reduction Effect ◽  
Single Number ◽  
Sound Reduction ◽  
Floor System ◽  
The Impact ◽  
Existing Housing

In Korean residential buildings, floor impact sounds were reduced over the past few decades mainly through a floating floor system. However, ceiling constructions for impact sound reduction have not been applied actively because of a lack of useful information. This study focuses on the effects of wall-to-wall supported ceilings (WSC), which are designed with construction discontinuities between concrete slabs and ceilings, and the damping caused by porous absorbers for impact sound insulation. To examine the impact sound insulation according to ceiling conditions, measurements were performed in 25 floor–ceiling assemblies. The results indicate that ceiling treatment is mostly useful in reducing the floor impact sound. The floor impact sound owing to the WSC decreased by 2–7 dB and 2–8 dB in terms of the single number quantity for the tapping machine and rubber balls, respectively, compared with representative existing housing constructions wherein ceilings were attached on wooden sticks. Furthermore, the reduction effect of the WSC appeared to be more profound when it was applied to the floor–ceiling assembly with poor impact sound insulation. Thus, the WSC can be used to enhance the impact of sound insulation of existing housings without major repairs of floor structural layers.

Background subtraction in STEM energy-loss mapping

1984 ◽  
Vol 42 ◽  
pp. 568-569
Author(s):  
R.D. Leapman ◽  
K.E. Gorlen ◽  
C.R. Swyt
Keyword(s):  
Energy Loss ◽  
Signal To Noise Ratio ◽  
Statistical Error ◽  
Scanning Transmission Electron Microscope ◽  
Reference Image ◽  
Inverse Power Law ◽  
Transmission Electron ◽  
Least Squares Fit ◽  
Scanning Transmission ◽  
Single Number

The determination of elemental distributions by electron energy loss spectroscopy necessitates removal of the non-characteristic spectral background from a core-edge at each point in the image. In the scanning transmission electron microscope this is made possible by computer controlled data acquisition. Data may be processed by fitting the pre-edge counts, at two or more channels, to an inverse power law, AE-r, where A and r are parameters and E is energy loss. Processing may be performed in real-time so a single number is saved at each pixel. Detailed analysis, shows that the largest contribution to noise comes from statistical error in the least squares fit to the background. If the background shape remains constant over the entire image, the signal-to-noise ratio can be improved by fitting only one parameter. Such an assumption is generally implicit in subtraction of the “reference image” in energy selected micrographs recorded in the CTEM with a Castaing-Henry spectrometer.

Decay of Temporary Threshold Shift in Noise

1973 ◽  
Vol 16 (2) ◽  
pp. 267-270 ◽  
Author(s):  
John H. Mills ◽  
Seija A. Talo ◽  
Gloria S. Gordon
Keyword(s):  
Sound Field ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Band Noise ◽  
Lower Asymptote

Groups of monaural chinchillas trained in behavioral audiometry were exposed in a diffuse sound field to an octave-band noise centered at 4.0 k Hz. The growth of temporary threshold shift (TTS) at 5.7 k Hz from zero to an asymptote (TTS ∞ ) required about 24 hours, and the growth of TTS at 5.7 k Hz from an asymptote to a higher asymptote, about 12–24 hours. TTS ∞ can be described by the equation TTS ∞ = 1.6(SPL-A) where A = 47. These results are consistent with those previously reported in this journal by Carder and Miller and Mills and Talo. Whereas the decay of TTS ∞ to zero required about three days, the decay of TTS ∞ to a lower TTS ∞ required about three to seven days. The decay of TTS ∞ in noise, therefore, appears to require slightly more time than the decay of TTS ∞ in the quiet. However, for a given level of noise, the magnitude of TTS ∞ is the same regardless of whether the TTS asymptote is approached from zero, from a lower asymptote, or from a higher asymptote.

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