We have a new article for a numerical investigation on the sound insulation of ventilation windows which has been published in the Applied Acoustics. Please visit the journal website in this link.
Investigation of Chinese word recognition scores of children in primary school classroom with different speech sound pressure levels
New article for an investigation of Chinese word recognition scores of children in primary school classroom has been published. Please visit the journal website in this link.
Abstract:
Chinese word recognition (CWR) test was conducted by grades 3 and 5 children under the different conditions of reverberation time (RT), background noise level (BNL) and speech sound pressure level (SSPL) in three primary-school classrooms. The CWR scores and signal to noise ratios (SNRs) have been obtained at listening positions. Results show that the CWR score for grades 3 and 5 children increases with increase of SSPL, decrease of RT or increase of age, but it decreases with increase of BNL under the same conditions. For a mixed noise of 56 dBA (speech-spectrum-like noise and ambient noise), the CWR scores in the classroom for grades 3 and 5 children reach a peak at SNR of 15–20 dBA under the same RT and age of children condition. For the natural ambient noise, the CWR score for grades 3 and 5 children gradually increases with increase of the SNR. The high SSPL could not guarantee good CWR for children in classroom, which also depends on RT and BNL in classroom. When the classroom has long RT or high BNL, the increase of SSPL would not be necessarily to achieve better CWR. The novelty of the present study is to further evaluate and confirm the results under environments of real classrooms (not simulated room in laboratory).
Classroom of a school in China
An impedance-mobility model of acoustic metamaterials
A fast prediction method for the performance of stacked membrane-type metamaterials has been developed using An impedance-mobility model. Matthew Blevins of the University of Nebraska-Lincoln introduced the method and a Matlab platform regarding this approach at the Spring 2015 meeting of Acoustical Society of America. The work is collaborated and supervised by Dr. Siu-Kit Lau and Dr. Lily Wang. Metamaterials are man-made materials to have properties that have not yet been found in nature. Membrane-type acoustic metamaterials have been proven to exhibit high low-frequency transmission loss despite their small thickness and light weight. The efficient model based on the impedance-mobility can be used to facilitate design and optimization of stacked membrane-type acoustic metamaterials.
Abstract (metamaterials) of the presentation in the ASA meeting spring 2015 in Pittsburgh, PA
An investigation of acoustic treatment for children in a classroom of an elementary school
The South China Univeristy of Technology and Dr. Lau of Armstrong have compared the objective acoustic parameters and students’ subjective responses before and after an acoustic treatment in an elementary-school classroom. Acoustic treatment was done by installing sound absorption materials on the ceiling of the classroom for control of sound reverberation. The effects of reverberation time on children’s speech recognition have also been investigated. Results show that (1) the objective acoustic parameters in the classroom were obviously improved; (2) the subjective loudness of different types of noise sources, that students experienced in the classroom, were reduced; and (3) the speech intelligibility was significantly improved in the classroom after the acoustic treatment.
The article can be found from this link.
Certificate of Reviewing from Applied Acoustics (Journal)
Elsevier Certificate 2014
Dr. Siu-Kit (Eddie) Lau awarded a Certificate of Reviewing from Applied Acoustics (Journal).
Cover page for Science (Journal) in January 2014 by Caleb Sieck
Cover page of Science on Jan 2014 (Source: Science, http://www.sciencemag.org)
Congratulations to Caleb Sieck! He has a publication of cover page for Science (journal) in January 2014! Science (journal) is a world leading journal of scientific research with very high impact factor (over 31 in 2012). The article shows the results of a circulator for sound, which sound can be guided to flow in particular directions, but not in the opposite directions. Caleb was advised by Dr. Siu-Kit Lau on his MS degree in UNL in 2009 to 2013 for “Investigation of Sound Transmission through an Open Window into a Room“. He is now studying his PhD in University of Texas at Austin with a topic related to metamaterials.