Canadian Acoustics https://jcaa.caa-aca.ca/index.php/jcaa <p>This quarterly journal is free to individual members of the Canadian Acoustical Association (CAA) and institutional subscribers. <strong>Canadian Acoustics</strong> publishes refereed articles and news items on all aspects of acoustics and vibration. It also includes information on research, reviews, news, employment, new products, activities, discussions, etc. Papers reporting new results and applications, as well as review or tutorial papers and shorter research notes are welcomed, in English or in French.</p> en-US <p>Copyright on articles is held by the author(s). The corresponding author has the right to grant on behalf of all authors and does grant on behalf of all authors, a worldwide exclusive licence (or non-exclusive license for government employees) to the Publishers and its licensees in perpetuity, in all forms, formats and media (whether known now or created in the future) <br>i)&nbsp;&nbsp; &nbsp;to publish, reproduce, distribute, display and store the Contribution;<br>ii)&nbsp;&nbsp; &nbsp;to translate the Contribution into other languages, create adaptations, reprints, include within collections and create summaries, extracts and/or, abstracts of the Contribution;<br>iii)&nbsp;&nbsp; &nbsp;to exploit all subsidiary rights in the Contribution,<br>iv)&nbsp;&nbsp; &nbsp;to provide the inclusion of electronic links from the Contribution to third party material where-ever it may be located;<br>v)&nbsp;&nbsp; &nbsp;to licence any third party to do any or all of the above.<br><br></p> editor@caa-aca.ca (Prof. Umberto Berardi) Fri, 04 Oct 2019 00:00:00 +0000 OJS 3.1.2.1 http://blogs.law.harvard.edu/tech/rss 60 Deaf Cultural Identification, Cochlear Implants, and Life Satisfaction https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3345 <p>Cultural identification within the Deaf community is a new field of research that looks at the differences in acculturation between deaf individuals. Glickman (1993) created a Deaf Identity Development Theory, which outlines that deaf individuals either identify with the hearing community, the deaf community (immersion), both communities (bicultural), or do not necessarily identify with either (marginal). Research has not looked directly at the effects cochlear implants (CI’s) have on the overall life satisfaction and well-being of these individuals and how the implants may create changes to their cultural identification. This study examined the link between cochlear implants, Deaf cultural identification and overall life satisfaction within the Deaf community and hypothesises that individuals with cochlear implants and strong culture identification will show significantly higher levels of overall life satisfaction than those who do not. A sample of deaf individuals ages 18 and older were given three measures: the Deaf Identity Development Scale (DIDS), the Deaf Acculturation Scale (DAS) and the Satisfaction with Life Scale (SWLS). The results found a significant correlation between life satisfaction and cultural identification, but no significant correlation between CI’s and life satisfaction or cultural identification.</p> Kristen Elizebeth Mulderrig, Sean Rogers Copyright (c) 2019 Kristen Elizebeth Mulderrig, Sean Rogers https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3345 Wed, 16 Oct 2019 14:49:12 +0000 Hearing Protectors Fit-Testing Using Smartphones: Preliminary Data https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3332 <p>To quickly estimate the amount of attenuation provided by any given hearing protection device (HPD) on any given individual, a smartphone app has been developed. The app features an audio stimulus generator to generate loud tones over the smartphone (or tablet) embedded loudspeakers, a graphical user interface where the user can report the count of audio stimuli perceived, and an attenuation prediction algorithm able to estimate the overall attenuation of the HPD under test, only knowing its type. The proposed approach relies on a supra-threshold method where sequence of 1 kHz-centered narrowband stimuli are played in decreasing levels with steps of 5 dB. The user simply counts the number of tonal bursts perceived before stimuli become inaudible in two conditions: with open ears and with both ears occluded with the HPD. The two counts values are entered within the app to compute an estimate of the overall HPD attenuation. This estimate is computed&nbsp;&nbsp;using the “octave band method” as an C-A overall attenuation, that represents the average difference between the C-weighted overall sound pressure level and the A-weighted overall sound pressure level attenuated by the HPD. The measured attenuation values using REAT and using the tablet are compared for two types of earplugs: a roll-down foamplug and premoded earplug. They show that while the REAT values obtained at 1 kHz are poorly predicted, the overall REAT attenuation values are better predicted and that a polynomial regression model could possibly be built to predict with reasonable accuracy the overall attenuation of foamplugs -and many other types of HPDs- using only a tablet or smartphone generating 1 kHz tonal bursts.</p> Jeremie Voix Copyright (c) 2019 Jeremie Voix https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3332 Wed, 16 Oct 2019 16:00:56 +0000 Listening Effort in Eateries https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3324 <p>Eateries such as restaurants, cafeterias and food courts can be noisy. There tend to be large crowds of people talking, and sometimes there is also music increasing the level of background noise. Most eateries lack sound-absorbing treatments, such as curtains or carpet, contributing to the high level of noise. These factors force speakers in eateries to raise their voices and increase the effort they exert during listening, known as listening effort. Studies of the acoustical environment of restaurants have been limited to sound level measurements and questionnaires, but no objective measures of listening effort have been used as far as the authors are aware.</p> <p>This project aims to objectively measure the listening effort that participants exert while listening in noisy restaurants. To achieve this aim, 10-minute samples of ambient noise will be recorded from four restaurants, two “quiet” and two “noisy,” using a stereophonic headset and a digital recorder. Fifteen younger adult participants will be given a task in which they are asked to listen to sentences and repeat back the last word. These sentences will be presented among the recorded background noise. The background noise will be played at four different levels, whereas the level of the sentences remained constant. Listening effort will be measured objectively using functional near-infrared spectroscopy (fNIRS), a non-invasive optical brain imaging method. This method requires the use of a sensor pad affixed to participants’ foreheads, which contains light sources and light detectors. The light sources emit near-infrared light into the scalp above the prefrontal cortex (PFC), and the light detectors measure the amount of light that returns to the sensor pad. From this, the concentration of oxygen in the PFC can be calculated, which will serve as the primary measure of listening effort.</p> Alberto Behar , Joseph Rovetti, Mohammad Abdoli, Fran Copelli, Frank Russo Copyright (c) 2019 Alberto Behar , Joseph Rovetti, Mohammad Abdoli, Fran Copelli, Frank Russo https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3324 Wed, 16 Oct 2019 16:46:06 +0000 Associations Between Musical Experience and Auditory Discrimination https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3342 <table class="data" width="100%"> <tbody> <tr valign="top"> <td class="value" width="80%"> <p>Background: Auditory processing is affected by both musical experience and native language. However, which aspects of auditory perception are influenced by musical experience for which language groups is not known.</p> <p>Objectives: To identify how musical experience is related to auditory discrimination for English speakers, and to compare these results with previous literature on other languages.</p> <p>Design: Scores on the Goldsmith Musical Sophistication Index self-report questionnaire were correlated to six aspects of auditory discrimination. Auditory discrimination was measured using three two-choice forced decision tasks for simple pitch discrimination, simple duration discrimination, and complex duration discrimination.</p> <p>Results: Only pitch discrimination was significantly related to musical experience after correction for multiple correlations.</p> <p>Conclusions: Improved pitch discrimination has been associated with musical experience in many studies and in many language groups. However, other aspects of auditory perception appear to have a different relationship with musical experience depending on native language.There are many questions remaining, and a direct comparison of different languages for how musical experience affects auditory discrimination is needed.</p> </td> </tr> </tbody> </table> Cory McKenzie, Amberley Ostevik, Bill Hodgetts, Jacqueline Cummine, Daniel Aalto Copyright (c) 2019 Cory McKenzie, Amberley Ostevik, Bill Hodgetts, Jacqueline Cummine, Daniel Aalto https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3342 Wed, 16 Oct 2019 14:52:50 +0000 Features of Male- and Female-Produced Song in Black-Capped Chickadees (Poecile Atricapillus) Change Between Seasons https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3348 <table class="data" width="100%"> <tbody> <tr valign="top"> <td class="value" width="80%">Black-capped chickadees (Poecile atricapillus) are small, non-migratory songbirds that are commonly seen across much of North America. One of their primary vocalizations, the fee-bee song, has been well-documented in males and functions in both mate attraction and territory defense (Smith, 1991). Both of these functions are critical to fitness particularly in the spring during the breeding season, but less so during other times of the year. Use of this song by females has only recently been described and its function is not well understood (Hahn et al., 2013). In this experiment, we measured acoustic features related to frequency and duration of both male- and female-produced fee-bee songs that had been recorded at two times of the year (e.g., spring and fall). We found that male songs showed less variation overall in their acoustic measures than female songs across both seasons. We also found that songs produced in the spring had less overall variation than those produced in the fall, regardless of sex of the producer. This suggests that fee-bee songs are more critical in the spring than fall, and also suggests that male song consistency may be more important than female song consistency. More research into the use and function of female song may elucidate these sex differences.</td> </tr> </tbody> </table> Kimberley Ann Campbell, Stephanie Thunberg, Christopher B Sturdy Copyright (c) 2019 Kimberley Ann Campbell, Stephanie Thunberg, Christopher B Sturdy https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3348 Wed, 16 Oct 2019 14:44:40 +0000 Generic Third-Octave Band Spectra For Construction Equipment https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3318 <table class="data" width="100%"> <tbody> <tr valign="top"> <td class="label">&nbsp;</td> <td class="value">A review of the literature on assessments of the impact of construction vibration on sensitive buildings and activities suggests that there is a reliance on total vibration levels without consideration of the spectra of different equipment. The author has reviewed a number of sources of information, including measurement reports, textbooks, and conference publications, in order to arrive at generic spectra for nineteen different types of construction equipment. The methodology relied upon the available information about total vibration levels and assumptions regarding different frequency regimes. At low frequency, a constant displacement was assumed that transitions at mid-frequencies to constant velocity, followed at high frequencies by constant acceleration. The resulting spectra from 1 Hz to 250 Hz correspond to the information available from other sources in a generic sense. The application of these construction-equipment spectra requires further information about the propagation losses of vibration from a construction site to a sensitive building or activity. Methods for documenting propagation losses are also addressed.</td> </tr> </tbody> </table> Todd Busch Copyright (c) 2019 Todd Busch https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3318 Wed, 16 Oct 2019 16:57:20 +0000 Radiation Efficiency Of Cross Laminated Timber Panels By Finite Element Modelling https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3320 <p>Tall wood buildings are growing in North America with the development of mass timber panels such as cross laminated timber (CLT). As a new building material, the sound radiation behavior is not well understood. This study proposes a finite element modelling (FEM) approach using ABAQUS finite element software to investigate the sound radiation efficiency of typical Canadian CLT panels with experimental elastic constants. The FEM method is first developed based on isotropic thin plate theory and verified with reported analytical solutions. Then one CLT panel with simple-support boundary conditions from literature is modelled as both thin and thick orthotropic plates under harmonic excitations. The radiation efficiency is calculated by post processing the sound power and velocity from FEM. The results have been compared with the reported experimental data and analytical data based on thin orthotropic plate theory. A general agreement is found between the FEM results and the literature results except some discrepancies at certain frequency bands. An attempt was made to investigate the effect of boundary conditions on radiation efficiency considering the real boundary condition realized in the lab. It is found that the boundary condition has some effect on the results, the clamped boundary condition seems to have better agreement than the reported simple support. Moreover, the FEM approach is adopted to evaluate the radiation efficiencies of different CLT panels made in Canada, namely 3-ply, 5-ply and 7-ply, using experimentally measured elastic constants. The results reveal that the influence of elastic constants on critical frequencies of different types of CLT panels. Under the critical frequency (up to 500 Hz), the elastic constants have a significant effect on radiation efficiencies.</p> Jianhui Zhou, Behzad Vafaeian, Ying-Hei Chui Copyright (c) 2019 Jianhui Zhou, Behzad Vafaeian, Ying-Hei Chui https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3320 Wed, 16 Oct 2019 16:56:26 +0000 Acoustical Considerations for Design-Build Mental and Behavioural Healthcare Facilities https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3346 <p>It is widely accepted that good quality healthcare environments are a key driver to patient wellbeing.&nbsp; There is evidence to suggest that acoustical quality may also have an important part in the recovery and treatment of patients suffering mental or behavioural health issues, with poor acoustic conditions seemingly exacerbating negative human-response effects such as irritability, anxiety, stress-related dementia and even lowered immune system symptoms.</p> <p>While there is a wealth of information, guidance and well-rehearsed best practice for the acoustical design and construction of mainstream healthcare buildings, it is often the case that the acoustical requirements for mental or behavioural health are simply assumed to be the same as for all other patient care facilities.&nbsp; In speaking to users groups, healthcare professionals and researchers it is clear that relying solely on traditional sound isolation or absorption treatments will not necessarily provide acoustical conditions that either promote patient wellbeing or provide sufficient safeguards to protect patient privacy.</p> <p>The challenges faced by designers, engineers and contractors in achieving an acoustical environment within successful and healthy treatment spaces requires careful consideration by the acoustician, with a delicate balance to be made between acoustic adequacy and patient safety.&nbsp; Building layout, adjacencies and the selection of materials and finishes requires scrutiny so that the completed building reflects not only the needs of patients and healthcare professionals but, which also ensures an efficient and cost-effective design-build process.</p> <p>The paper will present the challenges and constraints faced by designers, engineers and contractors in achieving a successful design for mental or behavioural health facilities and will discuss and evaluate contemporary examples of acoustical treatments and noise control measures used within mental or behavioural treatment facilities located in Western Canada.</p> Paul Marks Copyright (c) 2019 Paul Marks https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3346 Wed, 16 Oct 2019 14:47:10 +0000 Evaluation of an Indoor Open Space’s Acoustical Quality – A Case Study https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3321 <p>In this paper, selected acoustical parameters were used to evaluate the acoustical qualityof an indoor open space. The parameters included the sound pressure level, reverberationtime, and speech transmission index. The selected parameters were also used to calibrateand verify the accuracy of an indoor acoustic model. Next, room treatment measureswere incorporated into the model, for the purposes of improving the test space’sacoustical quality. The revised acoustic model showed the room treatments were effectiveat improving the space’s acoustical quality and confirmed the effectiveness of using thecalibrated acoustic model process. The playback of the convolved audio signaldemonstrated a reduction in the reverberation time and improvement with speechintelligibility. This paper demonstrates that the acoustical model can be used in themodelling of other spaces such as open-plan offices and industrial facilities. Acousticaltreatments, if required, can be verified in the model.Keywords: room acoustics, impulse, reverberation, speech transmission index, CadnaR.</p> Weidong Li, Linda Drisdelle Copyright (c) 2019 Weidong Li, Linda Drisdelle https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3321 Wed, 16 Oct 2019 16:55:34 +0000 The Case For Minimum Impact Noise Requirments in The National Building Code of Canada https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3329 <p>In the latest 2015 revision of the National Building Code of Canada (NBCC), Section 5.8 and 9.11 underwent significant changes to finally recognize minimum airborne field performance criteria and flanking sound transmission. Yet the revised NBCC again failed to mandate any minimum require- ment for impact noise isolation for multi-family dwellings, several decades after Canada’s interna-tional peers began implementing mandatory minimum requirements. This is despite a stated objec- tive of the Code to provide “noise protection” to building occupants. A recent code change request submitted in 2016 proposed the inclusion of impact noise protection in the NBCC, including mini- mum IIC/AIIC performance levels and methods of demonstrating compliance.</p> <p>In this paper, we present the case for prioritizing and requiring mandatory, minimum impact noise criteria in the NBCC by synthesizing the submitted NBCC Code change request. This includes a summary of previous research related to: the objectives of the Canadian National Building Code with respect to noise; A comparison with other developed countries; Canadian and International dwelling occupant satisfaction surveys concerning residential impact noise; the potential health effects as re- lated to impact noise sound levels and frequency; the structural changes required to the NBCC to introduce mandatory impact noise criteria; suitable criteria and enforcement mechanisms; and the various steps that can and should be taken by the Canadian acoustical community.</p> Matthew Golden, Roderick Mackenzie Copyright (c) 2019 Matthew Golden, Roderick Mackenzie https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3329 Wed, 16 Oct 2019 16:37:07 +0000 Complexities of Curtain Wall Flanking Transmission – A Case Study https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3338 <p>Curtain wall construction is very common in modern commercial buildings. The continuous external façade can lead to significant limitations on the sound isolation between adjacent rooms, separated either laterally or vertically. Flanking transmission of curtain wall systems is very difficult to predict at the design stage of a project. Manufactures do not routinely measure this parameter. The scarcity of data is partly due to a lack of laboratories that have the necessary specialized test environment. Generic flanking transmission loss data is of little value because of the large variation in curtain wall assemblies. Designers are often left with best guess approximations based on previous experience. These factors &nbsp;also &nbsp;make it difficult to significantly improve flanking transmission of an existing curtain wall installation.</p> <p>This paper describes a project where significant flanking along the curtain wall resulted in poor sound isolation between floors. Due to the complexity of the junction between the curtain wall and the floor structure, several potential flanking paths were identified and evaluated. It was possible to alter each flanking path individually so that the incremental improvement of each step could be quantified. After implementing several modifications, an improvement of approximately 15 dB was observed across a wide frequency range.</p> Kelly Kruger , Robert Ogle Copyright (c) 2019 Kelly Kruger , Robert Ogle https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3338 Wed, 16 Oct 2019 15:40:16 +0000 Recent Experience With Acoustical Privacy Considerations in Academic Settings https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3337 <p>Over the last number of years, the provision of increased levels of acoustical privacy and confidentiality has become an ever more important consideration in the design and functionality of office spaces and interview rooms. Occupants have always desired freedom from distraction and an enhanced feeling of privacy in their workplaces and offices. More recently, with the advent of privacy of information legislation, confidential levels of privacy are commonly required for spoken conversations. In academic settings, such spaces involve exam rooms for special needs students, mental health offices in student services facilities, cooperative education and other interview rooms and registration offices where sensitive information may be discussed. This article discusses several investigations related to reportedly poor levels of acoustical privacy in academic settings with regard to applicable criteria, suitable acoustical measurements and analysis and contributing factors.</p> Mandy Chan, William Gastmeier Copyright (c) 2019 Mandy Chan, William Gastmeier https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3337 Wed, 16 Oct 2019 15:42:16 +0000 A Comparative Evaluation of Hand-Arm Vibration Impacts https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3322 <p>Hand-arm vibration is a transmission of vibration from the use vibratory machinery or tools to a worker’s hands and arms. This paper looks at the attenuation characteristics of the frequency weighing curve&nbsp;<em>Wh&nbsp;</em>and presents some comparative results of vibration impacts from the use of several hand tools. Comparisons were made between the measurement methods prescribed by ISO standards and the data analysis of the raw vibration data. The results show that the measured impact as per the applicable ISO standards is significantly lower than the calculated vibration impact from the raw vibration data. This paper investigates other potential parameters that may be used to characterize the cumulative impacts from the hand-arm vibration. These additional analytical parameters may be used in evaluating the cumulative hand-arm vibration impacts in a more comprehensive way.</p> Weidong Li, Linda Drisdelle Copyright (c) 2019 Weidong Li, Linda Drisdelle https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3322 Wed, 16 Oct 2019 16:52:04 +0000 Development and Testing of an Aeroacoustic Wind Tunnel Test Section https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3334 <p>A new aeroacoustic wind tunnel test section is developed and tested at Carleton University. The aeroacoustic test section is fitted with two anechoic chambers on the two side walls. Side walls of the test section are lined with acoustic transparency tensioned cloth screens, which act as an interface between the test section and the anechoic chambers to provide a smooth flow surface while eliminating the need for a jet catcher and reducing interference effects. The test section is tested in the medium speed closed-loop wind tunnel at Carleton University. The design layout of the wind tunnel and design treatments to improve acoustic performance are discussed. Experiments are conducted to verify the acoustic performance of the developed aeroacoustic wind tunnel test section. It is found that background noise is comparable with other existing aeroacoustic wind tunnel facilities. The trailing edge noise of a NACA0012 airfoil model is also measured as a benchmark test. Results reveal that noise radiated from the airfoil trailing edge model are adequately higher than the background noise for a wide frequency range, and also that a sawtooth serrated trailing edge is effective for reducing noise compared to a straight trailing edge.</p> Basim Al Tlua, Joana Rocha Copyright (c) 2019 Basim Al Tlua, Joana Rocha https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3334 Wed, 16 Oct 2019 15:52:34 +0000 Intentional Yaw Misalignment and the Effects on Wind Turbine Noise https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3327 <p>A case study will be presented where a number of wind turbines in a project were intentionally yaw misaligned to investigate various effects. This paper investigates changes in sound level and special characteristics of wind turbine noise (amplitude modulation) due to the intentional yaw misalignment.</p> Ian Bonsma, Nathan Gara, Brian Howe Copyright (c) 2019 Ian Bonsma, Nathan Gara, Brian Howe https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3327 Wed, 16 Oct 2019 16:38:20 +0000 Comparison of Results From The STEAM Rail Noise Model to Potential Alternatives https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3349 <p>The “Sound from Trains Environmental Analysis Method” (STEAM) for rail noise prediction, created by the Ontario Ministry of the Environment (now the Ministry of Environment, Conservation, and Parks), has been in use in Ontario since 1990 and is endorsed not only at the provincial level in Ontario but also by the Canada Transportation Agency (CTA) for use in sound level predictions as they relate to complaint resolution for federally regulated railways.</p> <p>This paper presents a high-level comparison of the sound level predictions from the STEAM model to those currently in use in the United States – namely the Federal Transit Administration (FTA) and Federal Railway Administration (FRA) models.&nbsp; The comparison looks at the sensitivity of the models to a number of variables with a focus on sound emission characteristics.&nbsp; The investigation gives specific consideration to the impact of source selection (type of locomotive, type of car, etc) on the sound level predictions.</p> Ian Matthew, Anthony Amarra Copyright (c) 2019 Ian Matthew, Anthony Amarra https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3349 Wed, 16 Oct 2019 14:43:30 +0000 Minimizing Sonic Boom Noise to Meet Potential Regulatory Limits https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3333 <p>Sonic boom noise is predicted from parameters including aircraft weight, volume, shape, and standard atmospheric models. The acoustic field near the aircraft is calculated based on a cylindrical approximation to the aircraft shape and a variable lift distribution. Sound is propagated from the aircraft to the ground by considering both the sharpening of the boom due to shock ageing, and the softening of the sound due to frequency dependent atmospheric absorption. The resultant pressure signature at ground level is converted to a perceived sound level and compared to a maximum proposed noise limit of 75 dB. Obtained results are verified using NASA’s PCBoom program as well as with selected ground measurements for supersonic flights. Preliminary results show that inoffensive supersonic flight may require either high altitudes, or aircraft that are smaller and lighter than most common airliners.</p> John Halpenny, Joana Rocha Copyright (c) 2019 John Halpenny, Joana Rocha https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3333 Wed, 16 Oct 2019 15:53:29 +0000 Investigation of Aircrew Noise Exposure Due to The Use of The Intercom system Onboard The RCAF CH-149 Helicopter https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3340 <p>The National Research Council (NRC) Flight Research Laboratory (FRL) conducted a series of intercom signal voltage measurements on several CH-149 aircraft at RCAF Comox CFB in March 2019. The purpose of this test campaign and reporting was to support the Department of National Defence (DND) in investigating several issues related to the intercom system such as: multiple types of squelches reported by aircrew as well as to quantify the aircrew noise exposure levels due to the use of the CH-149 intercom system.</p> <p>Spectral analysis of the CH-149 intercom voice signal indicated the presence of high squelch noise levels and multiple tonal frequency peaks. Different types of squelch were analyzed and similarities as well as differences were discussed.</p> <p>Further analysis of the voice communication signals showed that the CH-149 intercom system was the source of significant noise amplitude levels during squelch events. The CH-149 intercom system introduced an averaged A-weighted OSPL at the aircrew ear entrance location of 96.5 dB(A) during regular flight communications. During squelch events, aircrew were exposed to an averaged A-weighted OSPL at the aircrew ear entrance location of up to 112.7 dB(A). Combining the helicopter cabin background noise and intercom communication noise will provide a more realistic estimate of CH-149 aircrew noise exposure during in-flight missions.</p> <p>Based on this investigation, several types of squelch noise events were recorded and evaluated for the CH-149 helicopter intercom voice communication. In particular it was concluded that proper selection and use of hearing protection devices as well as mitigation of the squelch events were important factors to alleviate the auditory risk for aircrew and improve speech intelligibility during flight missions on-board the CH-149.</p> Victor Krupka, Sebastian Ghinet, Yong Chen, Andrew Price, Viresh Wickramasinghe, Anant Grewal Copyright (c) 2019 Victor Krupka, Sebastian Ghinet, Yong Chen, Andrew Price, Viresh Wickramasinghe, Anant Grewal https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3340 Wed, 16 Oct 2019 15:37:59 +0000 Hearing Protection Performance Evaluation of Active Noise Reduction Headsets Under High Intensity Noise Levels https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3341 <table class="data" width="100%"> <tbody> <tr valign="top"> <td class="value" width="80%"> <p>High levels of noise within airborne or ground vehicles affect crew communication and prolonged exposure may lead to hearing-related damage if insufficient hearing protection is implemented. These acoustic environments are unique and varied based upon sources that generate tonal noise, broadband noise and impulsive noise.</p> <p>One of the recommended solutions to mitigate the auditory risks of working in high noise intensity levels was to utilise hearing protectors with Active Noise Reduction (ANR) systems. Investigation was required in order to establish if performance degradation should be expected, the goal being to determine if further more comprehensive performance assessments would be required for hearing protectors with ANR.</p> <p>In the present study, the four David Clark headset models e.g. 40600G-15, 40600G-20, 40750G-01 and H10-76XL were tested at various sound pressure levels such as 111 dB, 115 dB, 120 dB, 125 dB and 131 dB. As a result of this evaluation, it was observed that the performance of the four headset systems with ANR ON was repeatable and constant for noise excitation levels below 120dB.</p> <p>However, as is demonstrated by the preliminary evaluation, the insertion loss performance of the four headsets with ANR systems ON, when exposed to unweighted overall sound pressure levels (OSPL) superior to 120dB, significantly degraded with each increasing noise level increment. It is also very important to mention that the passive hearing protection performance of the four headsets (ANR OFF) remained, as expected, consistent (no degradation observed) at all high intensity noise levels considered in this study.</p> It will be shown that the performance of the hearing protectors with ANR electronic systems has to be consistently evaluated at various noise levels in order to accurately assess their expected performance in real life mission environment for personnel exposure to high intensity noise levels above 120dB.</td> </tr> </tbody> </table> Victor Krupka, Sebastian Ghinet, Viresh Wickramasinghe, Anant Grewal Copyright (c) 2019 Victor Krupka, Sebastian Ghinet, Viresh Wickramasinghe, Anant Grewal https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3341 Wed, 16 Oct 2019 14:54:07 +0000 Developing The Port of Vancouver’s Port Noise Rating Methodology https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3339 <table class="data" width="100%"> <tbody> <tr valign="top"> <td class="value" width="80%"> <p>The Vancouver Fraser Port Authority manages Canada’s largest port, the Port of Vancouver, encompassing federal port waters, lands, and shorelines in and around Vancouver, BC. In total, port-managed areas border 16 municipalities. As urban densification has increased near port operations, so too has the potential for port-related noise to disturb nearby communities.</p> <p>Between 2013 and 2015, to better understand port-related noise in nearby communities and address community noise concerns, the port installed 11 permanent noise monitoring terminals (NMTs) along the north and south shores of Burrard Inlet and at Roberts Bank. The NMTs continually log sound data in or near communities potentially affected by port noise.</p> <p>In order to provide value from this data to the port and its stakeholders, BKL developed a Port Noise Rating (PNR) metric which relates the measured sound pressure levels to the potential annoyance in the surrounding population using noise modelling and census data. The PNR metric provides a useful way for the port to interpret the significance of measured noise levels, changes over time, and differences between NMTs. However, the accuracy of this approach depends on many noise source modelling assumptions due to the complex noise environments that exist throughout the port’s jurisdiction.</p> <p>This paper summarizes the methodology BKL developed in partnership with the Vancouver Fraser Port Authority to calculate and present the PNR, including NMT configuration, local housing and population review, noise source identification, data analysis, and noise modelling.</p> </td> </tr> </tbody> </table> Mark Bliss, Gary Mak Copyright (c) 2019 Mark Bliss, Gary Mak https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3339 Wed, 16 Oct 2019 15:39:06 +0000 Innovative and Feasible Noise Mitigation Planning https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3336 <p>For industrial sites located near residential areas, noise pollution can be a limiting factor in expanding production. When KFP Inc. wanted to upgrade machinery and increase their annual throughput, they faced challenges dealing with increasing noise levels above acceptable limits at the neighbouring residential community. They needed a solution that would achieve continuous noise shielding, but a permanent noise barrier wall would cost millions of dollars and extend the project timeline. We envisioned a way to arrange for stacks of logs to be used as noise barriers and developed a plan to maintain continuous shielding even as the log inventory is removed for processing. The log wall changeover plan was developed through implementation of parallel walls system. By prototyping this barrier and completing the changeover process with sensors in place, we confirmed that our noise mitigation strategy was successful. This solution demonstrates the value and viability of using available onsite materials to provide noise mitigation and suggests the approach can be applied more widely. With good design, thorough investigation, and creative planning, regulatory compliance and improved noise environment for sensitive receptors in proximity of industrial facilities can be achieved.</p> Amir A. Iravani, Lucas Arnold Copyright (c) 2019 Amir A. Iravani, Lucas Arnold https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3336 Wed, 16 Oct 2019 15:46:48 +0000 Studying noise assessment and policies to influence noise management in Quebec https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3344 <p>Following a recent advisory on a policy to control environmental noise, the government of Quebec launched five research projects since 2018. &nbsp;With founding from the healthcare and from the environment ministries, academic researchers were asked to explore various aspects of noise assessment to stimulate governmental reflections in the province. &nbsp;Different topics include sound mapping as an evaluation tool, sound insulation of the building envelope and exposure values that would be considered in the interpretation of annoyance disturbing people. &nbsp;The Department of Geomatics Sciences and the School of Architecture from Laval University are involved in those projects. &nbsp;As part of the consultation process and aiming to collect various inputs from the professional community, the whole team is looking for significant comments before being able to make suggestions on how to improve noise management with appropriate justification.</p> Jean-Philippe Migneron, Jean-François Hardy, André Potvin, Jean-Gabriel Migneron, Frédéric Hubert Copyright (c) 2019 Jean-Philippe Migneron, Jean-François Hardy, André Potvin, Jean-Gabriel Migneron, Frédéric Hubert https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3344 Wed, 16 Oct 2019 17:55:32 +0000 Differences in Sound Exposure Results From Firearm Discharge Due to Measurement Equipment Selection https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3351 <p>Impulse sound from firearms discharge has high sound level but short duration.&nbsp; An accurate determination of soud exposure under these conditions requires suitable measurement equipmen.&nbsp; This paper will compare the sound exposures determined using a standard sound level meter at approximately 48 kHzwith equipment measuring at the MIL-STD-1474 rate of 200 kHz and at an intermediate sampling rate of 100 kHz.&nbsp; A variety of firearms is used for comparison, to address differences in the source.</p> Peter VanDelden, Philip Tsui, Alec Medemblik Copyright (c) 2019 Peter VanDelden, Philip Tsui, Alec Medemblik https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3351 Wed, 16 Oct 2019 14:05:09 +0000 Production Study of Spanish Spirantization in Naturalistic Speech https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3323 <p>Spanish spirantization is often cited as a case of phonetic reduction, in which oral closure movements are suggested to be produced in a failed/reduced form, and/or where speech muscles fail to achieve full activation. Other analyses treat spirantized variants as categorically distinct. The present study examines Spanish productions of the alveolar plosive /d/ in relation to its interdental variant in videos of natural speech produced by 12 Spanish speakers. Tokens of /d/ were contrasted to that of voiceless and nasal targets. Tokens were extracted, transcribed and coded for stress pattern and phonological environment by trained phoneticians. The area of visible tongue for /d/ in each video frame was measured and normalized. Differences in visible production indicate different active muscle groups for the dental /d/ vs. tongue protrusion in the interdental spirant. ANOVAs were performed on the area measurements, and chi-squared analyses were performed on the voiced, voiceless and nasal targets. Results indicate a bimodal distribution in tongue areas, indicating that the spirantized variants are produced with intent to achieve a separate target. This view is compatible with a modular approach to speech motor behavior.</p> Gracellia Purnomo, Gloria Mellesmoen, Arian Shamei, Bryan Gick Copyright (c) 2019 Gracellia Purnomo, Gloria Mellesmoen, Arian Shamei, Bryan Gick https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3323 Wed, 16 Oct 2019 00:00:00 +0000 Spectral Moments to Describe Fricative Emergence of French-Quebec Children https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3326 <p>Introduction</p> <p>In the study of fricatives, various acoustic measurements have been described to objectify the classification of these consonants. One of the measures most used is the analysis of spectral moments. There are four spectral moments used to describe these patterns: center of gravity, standard deviation, skewness and kurtosis. The acquisition of fricative consonants is well documented in English-speaking children. However, studies conducted in languages other than English, such as Japanese, have revealed differences in the order of acquisition of these consonants. These differences would indicate that some phonological development trends are specific to each language and, consequently, the English data may not be sufficiently sensitive to evaluate the phonological development of non-English-speaking children. In this study, we aim to obtain acoustic measurements that describe the phonetic-phonological development of fricative consonants in French from Quebec.</p> <p>Methods</p> <p>This cross-sectional study is developed on the data of 47 children, from Quebec City. The children's productions of the fricatives were obtained through a picture naming task. The observations were labelled and transcribed phonetically, with a double entry of 10% of the corpus.</p> <p>Results</p> <p>The analysis by mixed models show an effect of the point of articulation on the center of gravity and on the duration. The analyses showed an effect of the point of articulation on the standard deviation. An effect of the voiceless on the center of gravity and on the duration is also observed. Finally, there is an effect of age on duration.</p> <p>Discussion</p> <p>Preliminary results indicate that the center of gravity is the most robust spectral moment to classify the fricative consonants of preschool children, which coincides with previous literature. On the other hand, duration, a measure often described as secondary, appears to be a relevant indicator for the classification of fricative consonants of francophones children of Quebec.</p> Carolina Salinas-Marchant, Geneviève Meloni, Andrea A.N. MacLeod Copyright (c) 2019 Carolina Salinas-Marchant, Geneviève Meloni, Andrea A.N. MacLeod https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3326 Wed, 16 Oct 2019 16:39:15 +0000 L2 Production of American English Vowels in Function Words by Spanish L1 Speakers https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3328 <p>The present study investigates the production of American English (hereafter English) vowels in both function and lexical words by Spanish native speakers (n=62) and English native speakers (n=30) in recordings from the Speech Accent Archive (Weinberger &amp; Kunath, 2011). Vowels contained in English function words are often reduced (Jurafsky et al., 1998), while those in Spanish are less so (Hualde, 2005). Thus, the Spanish speaker learning English must learn not only a new vowel inventory but also the process of reducing these vowels in function words. The majority of research on L2 speech has focused on vowels in lexical items, a literature gap that the current study addresses. The recordings were analyzed acoustically in Praat (Boersma &amp; Weenink, 2016), where the first two formant values of each vowel token were extracted from the vowel midpoint. Formant values were normalized with the “Nearey Intrinsic” method in phonTools (Barreda, 2015). &nbsp;As age of onset of acquisition (AOA) is known to affect L2 pronunciation, the Spanish L1 speakers were split into two groups based on AOA. Both learner groups’ productions were compared to those of native speakers with a MANOVA run for each vowel, with normalized formant values as the dependent variables, and L1 as the independent variable. Pillai scores from the MANOVAs were used as a measure of vowel overlap (Hay et al., 2006). Pairwise comparisons were also run between vowels within groups to determine the extent of vowel neutralization in function words. In function words, the low AOA group patterned closely with the native speaker group, showing complete neutralization of some vowels and partial neutralization of others. The high AOA group showed partial neutralization of vowels in function words, which did not happen in lexical items. Results are discussed in the context of L2 speech learning theories and general phonetic theory.</p> Scott James Perry, Benjamin V. Tucker Copyright (c) 2019 Scott James Perry, Benjamin V. Tucker https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3328 Wed, 16 Oct 2019 16:07:39 +0000 Speech Perception and The Role of Semantic Richness in Processing https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3335 <p>The richness of meaning associated with specific words has been found to influence word recognition. Such findings, however, have come largely from studies based on visual word recognition, and related studies focusing on the acoustic signal and speech perception are less common. The present work recognizes that any effects observed may vary across modalities, and explores semantic richness effects as they may pertain to the perception and processing of spoken language. Goh et al. (2016) describe an auditory lexical decision experiment where concreteness, valence, arousal, semantic neighborhood density, and semantic diversity are found to affect spoken word recognition. The stimuli used in their study were limited to a set of fewer than 500 words, most of which were concrete nouns. In our study, we expand the scope of the analysis to include 9,086 words taken from the Massive Auditory Lexical Decision database (MALD; Tucker et al., 2019), each with corresponding values for each of the semantic variables of interest. In complement to the results described by Goh and colleagues, generalized additive mixed modelling indicates significant effects of concreteness, valence, arousal, and semantic neighborhood density on response latency. No effect was observed for semantic diversity. These results suggest that the processing of acoustic signals is influenced by top down semantic effects, even in decontextualized environments. While the specifics of these effects differ by semantic variable, it appears that increased semantic richness facilitates spoken word recognition.</p> Filip Nenadic, Matthew C. Kelley, Ryan G. Podlubny, Benjamin V. Tucker Copyright (c) 2019 Filip Nenadic, Matthew C. Kelley, Ryan G. Podlubny, Benjamin V. Tucker https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3335 Wed, 16 Oct 2019 15:51:34 +0000 Forced-alignment of the sung acoustic signal using deep neural nets https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3350 <p>Sung speech shows significant acoustic differences from normal speech, both careful and spontaneous speech. To analyse and better understand why sung speech presents a unique challenge for tools such as forced aligners and automatic transcribers, we trained a deep neural network to extract phone-level information from a sung acoustic signal. The current best network takes as input raw audio from a singer and outputs time-aligned phoneme labels that predict the phoneme that the singer is producing at ten millisecond increments. We use audio data from the Folkways collection, as maintained by the University of Alberta Sound Studies Institute. The data consists of several folk songs, mostly sung acapella by a few individual singers. Before being used as training or testing data, each song was aligned by hand, sectioning off each individual phoneme that appears and setting the start and endpoint. The data is also cut into twenty-five millisecond frames spaced ten milliseconds apart. Each will receive a label from the network, which will be compared with the label given by the transcription in order to evaluate the network’s performance. To further increase the amount of training data, all of the data was duplicated and noise was added to them. The performance of the network is evaluated automatically during training by comparing the output label that the network chose for a given frame to the label assigned to that frame by the human transcriber. After all of the frames have been evaluated, the network is assigned an accuracy score that reflects how many labels it assigned correctly. By this method, we found that the acoustic differences between speech and sung speech are significantly different enough that the tasks require separate acoustic models. However, using training data from both genres increased the accuracy of the overall model.</p> Dallin A Backstrom, Benjamin V Tucker, Matthew C Kelley Copyright (c) 2019 Dallin A Backstrom, Benjamin V Tucker, Matthew C Kelley https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3350 Wed, 16 Oct 2019 14:42:14 +0000 Effects of Modality and Linguistic Materials on Memory in Younger and Older Adults https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3347 <table class="data" width="100%"> <tbody> <tr valign="top"> <td class="value" width="80%"> <p>Audiologists can test memory with&nbsp;auditory or visual stimuli. Visual tests are immune to hearing loss, whereas auditory tests are ecologically relevant. In a previous study, an auditory test was preferred to a visual test because it yielded a greater range of working memory scores; however, the linguistic properties of the materials were not matched across tests. In the current study, we compared auditory and visual tests with matched word-level and sentence-level materials. All participants completed four tests (2 modalities x 2 linguistic levels) with counter-balanced order of conditions. In each test, 100 items were presented, with five trials in each of setsizes (2, 3, 4, 5, 6). The number of words correctly recognized, judged and recalled was measured. In part 1 of the study, 32 younger adults were tested and linguistic level and modality effects were confirmed. In part 2 of the study, 32 older adults were tested and linguistic level effects were found. Across age, recall decreased with increasing setsize. There was a significant main effect of linguistic-level (word &gt; sentence) on recall. Notably, younger adults performed just as well as older adults on both auditory tests, whereas they performed worse on both visual tests.</p> </td> </tr> </tbody> </table> April Emily Pereira, Jenna Pattison, Kathleen Pichora-Fuller, Sherri Smith Copyright (c) 2019 April Emily Pereira, Jenna Pattison, Kathleen Pichora-Fuller, Sherri Smith https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3347 Wed, 16 Oct 2019 14:46:07 +0000 An Acoustic Analysis Of Cannabis-Intoxicated Speech https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3343 <p>Speech from medicinal users of cannabis was compared before and after the consumption of cannabis to determine whether cannabis-intoxication produces salient acoustic correlates within the speech stream.&nbsp;Eight participants completed a variety of elicitation tasks (reading, interviews, storyboards, sustained vowel phonation) before and after the consumption of cannabis. Measurements of voice-onset time (VOT), prosodic trajectory, and acoustic quality (jitter / shimmer) suggest that cannabis-intoxication results in a distinct acoustic profile. Intoxicated speech was characterized by significant and substantial increases to the variability of VOT, altered prosodic expression (reduced range and flatter trajectories), and decreased shimmer. These findings have implications for the utility of automatic detection methods in distinguishing cannabis-intoxication from the speech stream, which may be useful for medical or legal purposes. Furthermore, these findings may provide insight into the psychological and physiological effects of cannabis intoxication.</p> Arian Shamei, Sonya Bird Copyright (c) 2019 Arian Shamei, Sonya Bird https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3343 Wed, 16 Oct 2019 14:51:25 +0000 The Effects of Outer Space on Vowel Space https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3325 <p>After returning from the&nbsp;<em>Expedition 35&nbsp;</em>space mission<em>,&nbsp;</em>astronaut Chris Hadfield reported that he had learned to speak with a weightless tongue in space, and that his tongue and lips felt heavy on landing. Such comments indicate that gravity has a substantial effect on speech articulation. Previous work has investigated the effects of altered gravity in space travel on speech production [Yu &amp; Hansen (2017)&nbsp;<em>JASA</em>&nbsp;141, 1605], however the audio assessed was from the 1969 Apollo Moon landings, and thus of poor quality due to technological limitations. These technological limitations resulted in a lack of appropriate data, eg; F1 and F2 were only assessed for one vowel, with only F1 investigated for the remaining vowels. The present analysis makes use of higher quality audio from the more recent STS-134 mission in 2011, and investigates F1 and F2 of astronaut Mark Kelly before, during, and immediately after the STS-134 mission. Approximately 90 seconds of audio from each condition (1. pre-launch interview, 2. in-space interview, 3. post-landing tarmac interview) was assessed using automated alignment and formant extraction via the Dartmouth Linguistic Automation suite (DARLA). Plotted vowel spaces from each condition suggest substantial reduction of vowel spaces in both the in-space and post-landing conditions. Three way ANOVA’s comparing F1 and F2 across all conditions indicate significant differences for all high vowels, especially for F1 which corresponds to vowel height. These observations corroborate Chris Hadfield’s descriptions that altered gravity results in observable impairments to speech motor control.</p> Arian Shamei, Bryan Gick Copyright (c) 2019 Arian Shamei, Bryan Gick https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3325 Wed, 16 Oct 2019 16:40:16 +0000 EEG-to-F0: Establishing Artificial Neuro-Muscular Pathway For Kinematics-Based Fundamental Frequency Control https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3331 <table class="data" width="100%"> <tbody> <tr valign="top"> <td class="value" width="80%"> <p>The fundamental frequency (F0) of human voice is generally controlled by changing the vocal fold parameters (including tension, length and mass), which in turn is manipulated by the muscle exciters, activated by the neural synergies. In order to begin investigating the neuromuscular F0 control pathway, we simulate a simple biomechanical arm prototype (instead of an artificial vocal tract) that tends to control F0 of an artificial sound synthesiser based on the elbow movements. The intended arm movements are decoded from the EEG signal inputs (collected simultaneously with the kinematic hand data of the participant) through a combined machine learning and biomechanical modeling strategy. The machine learning model is employed to identify the muscle activation of a single-muscle arm model in ArtiSynth (from input brain signal), in order to match the actual kinematic (elbow joint angle) data . The biomechanical model utilises this estimated muscle excitation to produce corresponding changes in elbow angle, which is then linearly mapped to F0 of a vocal sound synthesiser. We use the F0 value mapped from the actual kinematic hand data (via same function) as the ground truth and compare the F0 estimated from brain signal. A detailed qualitative and quantitative performance comparison shows that the proposed neuromuscular pathway can indeed be utilised to accurately control the vocal fundamental frequency, thereby demonstrating the success of our closed loop neuro-biomechanical control scheme.</p> </td> </tr> </tbody> </table> Himanshu Goyal, Pramit Saha, Bryan Gick, Sidney Fels Copyright (c) 2019 Himanshu Goyal, Pramit Saha, Bryan Gick, Sidney Fels https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3331 Wed, 16 Oct 2019 16:02:00 +0000 Measuring the dispersion of density in head and neck cancer patients' vowel spaces: The vowel dispersion index https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3330 <p>The present study introduces a measure of the dispersion of density throughout the vowel space, which we refer to as the vowel dispersion index. The vowel dispersion index is based on calculating the total variation of the density values in Story &amp; Bunton’s (2017) convex hull representation of vowel space density. Overall, the vowel dispersion index quantifies how much change there is throughout the vowel space density. When the value is low, the speaker tends to produce most of their vowels in a central location like /?/, often characteristic of hypoarticulated or reduced speech. When the value is high, the speaker often spreads their vowel productions throughout the vowel space, as is characteristic of hyperarticulation. The vowel density index is calculated and analyzed for a small sample of recordings from head and neck cancer patients at different stages pre- and post-surgery. Consideration is given to 1) how the index corresponds with visual analysis of their vowel space density and 2) what the dispersion of density throughout the vowel space suggests about the communication strategies these patients employ while speaking. The vowel density index generally corresponds with visual impressions of the vowel space density. Additionally, the patients are overall found to employ hyperarticulation strategies to increase the clarity of the information in their speech post-surgery. These findings are discussed with respect to phonetic theory, principally, Lindblom’s (1990) H&amp;H theory.</p> Matthew C. Kelley, Daniel Aalto Copyright (c) 2019 Matthew C. Kelley, Daniel Aalto https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3330 Wed, 16 Oct 2019 16:03:04 +0000 CANADIAN PRAIRIE DIALECTS: AN EXPLORATION OF ALBERTA AND SASKATCHEWAN VOWELS https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3355 <p>Previous research has documented the English spoken in Western Canada as generally homogenous with minor variation along a spectrum from British Columbia to Northern/Western Ontario (Labov et al., 2005). This description is investigated on a narrower geographic scale, building a corpus of Southern Alberta and Saskatchewan English (SASE) and comparing the acoustic properties of SASE vowels to those of Edmonton English (EE) as observed in Thomson 2007. The corpus consists of 24 informal interviews as well as word list and passage readings. First and second formants were extracted from the word list (careful speech) context and measurable acoustic differences were found between this data and the EE description. Both speaker groups were found to have similar distributions, however /?/ and /?/ as well as /?/ and /?/ are closer to each other in SASE than in EE, suggesting possible mergers. SASE fronts /u/ and /?/, aligning with shifts noted in the western and southern United States (Clopper, 2005) but also fronts /?/, distancing itself from the Northern Cities Shift which instead describes a backing of /?/ (Labov et al., 2005). We also statistically explore differences in the vowel space using vowel overlap methods (Hay et al., 2006).</p> Bryce Jacob Wittrock, Benjamin V. Tucker Copyright (c) 2019 Bryce Jacob Wittrock, Benjamin V. Tucker https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3355 Thu, 17 Oct 2019 00:00:00 +0000 Acoustic Week in Canada 2020 Sherbrooke Conference Announcement https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3310 <p>Acoustics Week in Canada 2020 will be held on October 7-9, in Sherbrooke, Québec.</p> <p>&nbsp;You are invited to be part of this three-day conference featuring the latest developments in Canadian acoustics and vibration. Sherbrooke is well known in acoustics for the Groupe d’Acoustique de l’Université de Sherbrooke (GAUS) founded in 1984.</p> <p>The conference will be an excellent opportunity to visit or rediscover the GAUS during the International Year of Sound!</p> Olivier Robin Copyright (c) 2019 Olivier Robin https://jcaa.caa-aca.ca/index.php/jcaa/article/view/3310 Thu, 03 Oct 2019 00:00:00 +0000