Showing papers in "Canadian Acoustics in 2017"

Destructive interferences created using additive manufacturing

Abstract: Current solutions to absorb sound have technical limitations in being tailored to the specific acoustic requirements of a space. In fact, porous materials show high absorption at higher frequency, while at low frequency, the use of porous materials often require an impracticable significant thickness. Alternatively, resonance absorption mechanisms (either Helmholtz resonators or vibrating panels) show low frequency absorption but in limited frequency ranges. This research focuses on absorbers created using additive manufacture in order to absorb in the low frequency rage using passive destructive interference principles. Additive manufacturing allows for the fabrication of unique pieces with complex and freeform curved geometries. Focusing on geometrical aspects, this paper presents the results of the investigation of an ongoing project to create a large thin transparent panel with absorption above 0.6 below 250 Hz with limited thickness.

Acoustic Of A Chamber Music Hall Inside A Former Church By Means Of Sound Energy Distribution

Abstract: The present work concerns the acoustic design for a former church converted into a chamber music hall. The current status of the hall was classified with an acoustic measurements campaign according to technical standards requirements. Focusing on literature theories, an accurate sound energy spatial distribution analysis led to the development of an acoustic intervention, not- invasive from a volumetric point of view. An array of hanging reflecting panels over the musicians' positions improves clarity C 80 and sound strength G trends giving to the church an acoustic quality worthy of a concert hall. All the acoustic treatments were validated using a numerical model, calibrated through the measured values, and an acoustic simulation software in order to estimate the effect of the whole improvement proposal.

Indie-Pop Voice: How a Pharyngeal/Retracted Articulatory Setting May Be Driving a New Singing Style

Abstract: Different genres of singing may be characterized in part by singers’ articulatory settings (Gick et al., 2004; Bateman,2003; Nair, Nair & Reishofer, 2016). Bateman (2003, p. 122), for example, notes that pop singing is often characterized by horizontal expansion and vertical compression of the lips, while jazz uses labial protrusion. The articulatory settings associated with a given singing style are known to have noticeable, systemic effects on the acoustics of the singer’s pronunciation (e.g. Ophaug, 2010). Recently, a new singing quality has emerged, sometimes called “indie-pop voice” (e.g. Ugwu, 2015). Initial popular descriptions focused on characteristic vowel pronunciations and unusual front-rising diphthongs, usually before coronal consonants. Careful observation suggests that, while the details and degree of these characteristics vary from artist to artist, they have in common a pervasive pharyngeal voice quality. We consider the possibility that a distinctive articulatory setting is used by “indie-pop”singers, which may be responsible for the observed effects on sung pronunciation. For the present study, we selected 8 contemporary pop artists, and took spectral measurements of the vowels from their successful songs, and from spoken interviews. Preliminary results reveal a high F1 across the “indie-pop" vowel space (particularily the front vowels), a strong correlate of pharyngealization. We also observed lower F2 in most vowels (particularily high-back), a correlate of retracted tongue-root (Aralova, 2011). Low-back vowels were exceptions to this, possibly because an articulatory setting with retracted tongue could be redundant with the low tongue position inherent to these vowels. Global tongue retraction may also explain the unusual diphthongs: the greater distance between the tongue’s vocalic position and a coronal target for the following consonant could lead to an audible transition. Normal 0 false false false EN-CA X-NONE X-NONE References Aralova, N., Grawunder, S., & Winter, B. (2011). The acoustic correlates of tongue root vowel harmony in Even (Tungusic). In Proceedings of the 17th International Congress of Phonetic Sciences (ICPhS XVII) (pp. 240-243). Bateman, L. A. (2003). Soprano, Style and Voice Quality: Acoustic and Laryngographic Correlates . M.A. Thesis. University of Victoria. Clements, G. N. (2015). The hierarchical representation of vowel height. Features in Phonology and Phonetics: Posthumous Writings by Nick Clements and Coauthors , 21 , 25. Gick, B., Wilson, I., Koch, K., & Cook, C. (2005). Language-specific articulatory settings: Evidence from inter-utterance rest position. Phonetica , 61 (4), 220-233. Gick, B. (1999). A gesture-based account of intrusive consonants in English. Phonology , 16 (01), 29-54. Nair, A., Nair, G., & Reishofer, G. (2016). The low mandible maneuver and its resonential implications for elite singers. Journal of Voice , 30(1), 128-e13. Ophaug, W. (2010). Sangfonetikk En innforing . Bergen: Fagboklaget. Ugwu, Reggie (2015). Selena Gomez’s “Good For You” And The Rise Of “Indie Pop Voice.” Buzzfeed.com. https://www.buzzfeed.com/reggieugwu/what-is-indie-pop-voice?utm_term=.qgvJ2GqJB#.buLX98zXp Normal 0 false false false EN-CA X-NONE X-NONE ...read moreread less

Cross-Linguistic Bracing: A Lingual Ultrasound Study of Six Languages

Abstract: Lateral bracing refers to contact of the sides of the tongue along the upper molars or palate; evidence from articulatory analysis of native English speakers as well as 3D biomechanical simulations suggests that bracing involves mechanical support which occurs consistently throughout speech [Gick et al. 2017. J Speech Lang Hear Res. 60(3):494-506]. Release of lateral bracing occurs only during some lateral consonants and low vowels. The current study tests for the presence of active lateral bracing in seven languages: Cantonese, English, Korean, Mandarin, Portuguese, Spanish, and Turkish. Ten native speakers of these languages (2 each for English, Mandarin and Korean and one each for the other languages) read aloud passages of the North Wind and the Sun [Handbook of the IPA, 1999] while a coronal ultrasound video of their tongue was recorded. Tracings were made from still images of the M-mode ultrasound videos, and measurements of the vertical motion of the tongue midline and both edges were taken. The percentage of time the tongue is not laterally braced was calculated. Active lateral bracing is implicated if the left and right edges of the tongue are less variable in vertical motion than midline and/or positioned at a stable baseline height for a larger percentage of time than they are lowered. Preliminary analysis supports the hypothesis that tongue bracing in speech exists regardless of language.

EARtrodes: Towards a wireless in-ear custom-fitted brain computer interface

Abstract: Brain-computer interfaces (BCI) can directly translate human intentions into discrete commands, bypassing the motor system. Most non-invasive BCI systems currently in use are based on electroencephalography (EEG) recording technology. While traditional EEG-based BCIs achieve high information transfer rates, these systems are facing important limitations. First, they cannot be used in daily life as they are bulky and sensitive to movement. Second, the scalp caps used to position electrodes are inadequate for social settings. To overcome these two limitations a portable and unobtrusive ear-EEG recording system was developed and tested against a traditional laboratory EEG system. The ear-EEG system senses brain-electrical signals from in and around-the ear, using custom-fitted earpieces. The objective of the current study is to assess if ear-EEG could produce results similar to the ones obtained from conventional EEG apparatus. Miniaturized wet electrodes were installed in a SonoFit™ custom-fitted in-ear audio platform developed by EERS (Montreal, Canada). This in-ear audio platform was coupled with a behind-the-ear piece forming a 5 mini electrodes interface. Auditory steady state responses (ASSRs) were collected with this prototype setup, dubbed “EARtrodes”, and compared to those obtained with a well-established, wired laboratory EEG recording system, the Rotman MASTER research system developed at the Baycrest Centre (University of Toronto, Canada). Although EARtrodes' signals show lower amplitudes, corresponding signal-to-noise ratios were similar with both systems. As a consequence, the proposed EARtrodes seems to be a promising candidate for future small, mobile, and unobtrusive BCI platforms, but further research is needed to investigate event-related potentials obtained from an auditory oddball and a mismatch negativity paradigm to further support such statement. In the long term ear-EEG systems like EARtrodes could be merged with other audio devices, such as hearing aids and headphones, to build next-generation devices that dynamically adapt to the listener’s intentions and cognitive state changes.

Ultrasound Study of Emphatics, Uvulars, Pharyngeals and Laryngeals in Three Arabic Dialects

Abstract: ifferent studies show different and to some extent inconsistent mechanisms for the articulation of Arabic uvular, pharyngeal and laryngeal sounds, i.e. gutturals, and emphatic sounds. The current study uses ultrasound imaging of the tongue to examine the articulations involved in guttural and emphatic sounds in three Arabic dialects, Egyptian, Saudi and Palestinian. This investigation attempts to answer the question: what are the tongue shapes during the production of both inherently retracted /ʕ, ħ, ʁ, χ, q/ and secondarily retracted /ðˤ, sˤ, tˤ, dˤ/ sounds. Articulatory results indicate that these sounds are produced with different tongue root and tongue dorsum retraction mechanisms. Pharyngeals are articulated with tongue root retraction and statistically do not involve significant tongue dorsum retraction. Uvulars and emphatics show tongue root and tongue dorsum retraction with inconsistent tongue root retraction. Laryngeals do not show any significant tongue retraction. Keywords: ultrasound, Arabic dialects, emphatics, uvulars, pharyngeals, laryngeals

Insertion loss of hearing protection devices for military impulse noise

Abstract: Military operators are exposed to different kinds of impulse noise sources, including small calibre weapon fire, heavy artillery fire and low-level blast from breaching exercises. For training purposes, limits for the number of exposures per day are indicated in training doctrines. However, there is often no background information on how the daily limits are calculated and insufficient guidance on the use of hearing protection devices (HPDs). With changing guidelines on impulse noise damage-risk criteria and evolving HPD technology, unit commanders often question the validity of the exposure limits and are uncertain about which HPDs to provide to their personnel. We have measured the impulse noise levels of several different Canadian Armed Forces (CAF) and Israel Defense Forces (IDF) weapons near the operator's ear, as well as the insertion loss of different types of HPDs using an acoustic test fixture (ATF). The peak levels of small calibre rifles and machine guns were in the range of 153 to 165 dB peak near the ear. The 1/3 octave band insertion loss results of passive and active earplugs showed that 1) different insertion loss levels were obtained for different types of noise sources and 2) the ATF measurements often exceeded the limits of bone conduction. The results suggest that it is not sufficient to measure only the peak insertion loss of an HPD; rather, the spectrum must be analyzed for different types of weapons and HPDs. This complicates the task of including HPD insertion loss in the calculation of daily exposure limits. Practical concerns for military operators, including compatibility of HPDs with other personal protective equipment and communication requirements, will also be discussed.

Acoustics of aero-acoustic wind tunnels – state of the art

Abstract: Wind tunnels continue to be used extensively for the development of aerospace vehicles and ground vehicles. An area seeing continued growth is in aero-acoustic testing. For aeronautical vehicles, primarily fixed wing aircraft and rotorcraft, the emphasis is on external noise sources. For ground vehicles, primarily cars and SUVs, the emphasis is on interior noise sources. The main focus of this paper is a general description of the aero-acoustic aspects of wind tunnels. Both open-jet and solid wall wind tunnels will be discussed. First, the genesis of the in-flow and out-of-flow sound pressure level specifications, over the past 20 years, will be outlined. Design concepts used to satisfy the acoustic specifications will be enumerated with examples. Finally, resonance and other acoustic issues will be discussed briefly. The solution techniques used to ameliorate the acoustical issues will be highlighted in this paper.

Effect of Vortex Formation Length on Flow-Excited Acoustic Resonance for a Single Spirally Finned Cylinder in Cross-Flow

Abstract: Over the years, some effort has been expended in the improvement of heat transfer performance in tubular heat exchangers by increasing the heat transfer area of the tubes This can be achieved by adding different types of fins to the outer surface of the tubes However, finned tubes may lead to the generation of acute noise problems, caused by the coupling between the vortex shedding frequency and one of the acoustic natural frequencies of the duct housing the tubes This may significantly reduce the service life of heat exchangers and may negatively impact the health of individuals working in close proximity to such acute noise intensity Since the phenomenon is not yet fully understood, it can be dangerously unpredictable Therefore, in this study, the flow-sound interaction mechanism of spirally finned cylinders will be investigated Five spirally finned cylinders are investigated, which have fin densities ranging between 2 to 7 fins per inch It has been observed that the addition of spiral fins induce an early flow separation, as compared to a bare cylinder This causes the separated flow to be convected further downstream, and as a result of this, the vortices form further away from the cylinder’s base As the fin spacing reduces, the vortex formation length gradually reduces due to a progressive delay in the boundary layer separation This has shown to inherently affect the radiated sound during resonance; where vortices formed further away from the cylinder base has shown to attenuate the sound pressure during acoustic resonance excitation A sample of the results are shown in this paper

Air Dome Acoustics

Abstract: Air dome is an air supported structure, it is a building composed by one or more layers of continuous flexible membrane anchored to the ground, inflated and supported by pressurized air. In the present work are shown results of acoustic measurements inside an air dome. In this type of structure reverberation time values, at the medium frequencies, are over 8 s and therefore with an excessive reverberation is significantly reduced ability to speech understanding that during training phases does not correctly allow to understand the instructions of coaches. With use of a software for architectural acoustics it was evaluated a possible acoustic correction for reducing reverberation time, by introducing into the turned area of air dome some sound absorbing material.

Using Optical Flow Analysis on Ultrasound of the Tongue to Examine Phonological Relationships

Abstract: This paper examines whether there are articulatory correlates of differing degrees of phonological contrast. English tense vowels are found to be produced with greater average magnitudes of movement when they occur in closed syllables, where they are generally contrastive with their lax vowel counterparts, than when they occur in open syllables, where they are less contrastive. Magnitude of tongue movement was determined by optical flow analysis of ultrasound videos of tongue movements; optical flow analysis allows for direct comparison of results across speakers and for the extraction of data from the entire timecourse of productions.

Effects of short-term choir participation on auditory perception in older adults.

Abstract: Hearing loss, which most adults will experience to some degree as they age, has been associated with decreased emotional wellbeing and reduced quality of life in aging adults. Although assistive technologies (e.g., hearing aids) can target aspects of peripheral hearing loss, persistent perceptual deficits are widely reported. One prevalent example is the loss of the ability to perceive speech in a noisy environment, which severely impacts quality of life and goes relatively unremediated by hearing aids. Musicianship has been shown to improve aspects of auditory processing, but has not been studied as a short-term intervention for improving these abilities in older adults. The current study investigates whether short-term choir participation can improve three aspects of auditory processing: perception of speech in noise, pitch discrimination, and the neural response to brief auditory stimuli (frequency following response; FFR). Forty-six older adults (aged 50+) participated in a choir for 10 weeks, during which they took part in group singing (2 hours/week) supported by individual online musical training (1 hour/week). Choir participants (n=46) underwent pre- and post-training assessments, conducted during the first week of the choir and again after the last week. Two control groups were assessed, including a group of older adults (aged 50+) involved in 10 weeks of music appreciation classes (music perception group; n=17), and an age- and audiometry-matched do-nothing control group (aged 50+; n=25). Control participants underwent the same battery of assessments, measured twice over the same time frame as the choir participants. Auditory assessments were administered electronically, and the FFR was obtained using electroencephalography (EEG). Preliminary statistical analyses showed that choir participants improved across all auditory measures, while both control groups showed no differences. These findings support our hypothesis that short-term choir participation is an effective intervention for neural and perceptual aspects of age-related hearing loss.

Hearing protector fit-testing: Spectrum uncertainty budgets

Abstract: Hearing protection devices (HPD) are widely used to protect workers exposed to dangerous levels of noise. Their effective attenuation can nowadays be routinely assessed using Field Attenuation Estimation Systems (FAES), colloquially referred to as fit-test systems. FAES typically rely on the Personal Attenuation Rating (PAR x% ), a single number factoring in the attenuation obtained at the seven octave band frequencies from 125 to 8000 Hz, and accounting for the spectrum uncertainty component resulting from the different attenuation profiles of HPDs across these frequencies. In the current study, this spectrum uncertainty has been computed, for many types of HPDs, from various published laboratory datasets, including the NIOSH Hearing Protector Device Compendium. The study includes a detailed spectrum uncertainty budget for the various categories of earplugs (roll-down foam, premolded, formable, push-to-fit, custom molded, etc.), semi-inserts and earmuffs. These values have been expressed at the 95 th percentile for a direct use in the upcoming ANSI S12.71 standard on FAES.

Acoustic performance of study rooms - a case study

Abstract: A new building at an academic institution was built for the purpose of providing students with needed space for individual and group study. The building had quickly turned into a preferred space and is often heavily occupied. The study rooms are equipped with televisions and the walls are coated with a whiteboard layer, so that both conversations/presentations can be undertaken in addition to silent study. There have been numerous complaints from users of the study rooms about the disturbances from the TV and those speaking in adjacent rooms. Students noticed that conversations were easily audible, even when speaking at normal levels. Two pairs of unoccupied study rooms were used to conduct tests and evaluate their acoustical performance. The Apparent Sound Transmission Class (ASTC) and Articulation Index (AI) ratings were calculated to determine if the study rooms are acceptable for students requiring a quiet workspace, while having their conversations kept private. The results of the study will be presented in this paper. Keywords: Apparent Sound Transmission Class (ASTC); Articulation Index (AI); group study room; school; speech privacy

Loudness in the occluded ear canal: Are we again missing 6 dB?

Abstract: Over the last century, a large number of studies were reported as related to the "case of the missing 6 dB". Initially, this research dealt with the loudness comparison between noise induced by circumaural headphones versus that induced by a free-field loudspeaker. It was said headphones had to generate more sound pressure in the ear canal to equal the loudness that a loudspeaker would provide. Some recent work has since provided several explanations for this observed discrepancy. Three main changing parameters were identified to describe this large amount of data that may or may not have been influenced by the same factors: nature of the source (loudspeaker, headphones, in-ear monitors), characteristics of the sound stimuli (spectral and temporal features, excitation level), and the mechanical load applied to the external ear (ear covered with earcups, occluded ear, fully open ear). In this paper, we intend to combine the thoughts of several decades of research and help providing the full picture on this issue for the occluded ear case. Based on our own experimental measurements and those from other inquisitive studies, focus was made on the factors that should be regarded as most likely to explain the observed differences for the occluded ear to perceive the same loudness as the open ear.

Voices in noise or noisy voices: Effects on task performance and appreciation

Abstract: Learning from orally presented information often requires distinguishing target signals from noise. Effects of background noise on information processing has been extensively studied, and it is clear that similarity between target and noise makes separation more difficult. Therefore, the question is what happens when noise is actually part of the target signal, which is the case for dysphonic voices. Dysphonia is defined as a speech disorder `characterized by the abnormal production and/or absences of vocal quality, pitch, loudness, resonance, and/or duration, which is inappropriate for an individual's age and/or sex.' (ASHA). In this study, information processing is investigated in two noise conditions that are thought to be very challenging: multitalker babble and dysphonic voices. The aim is to compare the effect of a noise source that is very similar to the target signal (speech) but clearly external, with the effect of noise sources that are inherently part of the signal (dysphonia). In addition, the combined effect, i.e. a dysphonic voice in multitalker babble, is studied as well. For information processing, task performance and subjective perception of difficulty are evaluated. Subjective perception varies most clearly with the different noise conditions. Reported difficulty increases significantly for multitalker babble and dysphonia separately, both compared to a healthy voice in quiet conditions. Remarkably, within multitalker babble no differences in rating between dysphonic voices and the healthy voice are seen; dysphonic voices are no longer rated more difficult than a healthy voice when this healthy voice is also presented within babble noise.

Teaching acoustics in architectural programs in canada

Abstract: The growing complexity of buildings requires students attending architecture schools to integrate many different specialized capabilities while still focusing on design principles and practices. First this paper reviews the breadth and depth education in acoustics among the 11 University Schools of Architecture in Canada which have been granted CACB Accreditation. The paper discusses the content and educational approaches followed in these schools. Then, the paper focuses on the recent evolution experienced at the Department of Architectural Science of Ryerson University.Teaching through project-oriented education has been recently introduced and the unique challenges of such an approach are discussed. This hands-on approach, focusing on both smartphone measurements and preliminary simulations, encourages students to develop a professional attitude for applying theoretical principles to the solution of acoustic basic problems.

Relationship Between Railway Ground-Borne Vibration Propagation And Track Elevation – A Field Study

Abstract: Railway corridors form vital transportation routes for moving goods and people across Canada. These routes have seen explosive growth of close proximity residential developments in Canada’s major cities and the impacts due to rail traffic on residences is a growing concern. A relationship between railway ground-borne vibration propagation and track elevation relative to points of reception was investigated and proposed based a field study of vibration measurements taken adjacent to railway corridors in Ontario and Alberta. The purpose of this study was to compare vibration measurements under three conditions: track elevated on berm, track at grade and track below grade, relative to points of reception. Other railway variables such as track condition, train speed and soil conditions were noted however were not assessed for this paper. Results of this study indicate track elevation is a factor in railway ground-borne vibration propagation. The importance of this relationship on land-use planning adjacent to railway corridors is discussed and existing guidelines for ground-borne vibration and vibration induced noise are summarized.

Acoustic analysis of emotional speech processed by hearing aids

Abstract: A talker’s emotional state is one important type of information carried by the speech signal. Past studies have shown that listeners with hearing loss have difficulties identifying vocal emotion. However, there is little research on how much hearing aids may ameliorate these difficulties. The amplitude compression performed by hearing aids makes words easier to recognize, but little is known about how such processing affects the emotional cues carried in the speech signal. The speech materials used in this study were sentences spoken by a young female actor portraying different vocal emotions. These sentences were processed using different hearing aid simulations: a flat 10 dB gain across frequencies; linear gain according to NAL-NL2 targets; fast amplitude compression, and slow amplitude compression. Acoustic analyses of the hearing aid-processed speech showed that the amplitude envelope was flattened by fast amplitude compression, more so for sentences spoken in Angry and Happy conditions than in other emotion conditions. Hearing aid processing using NAL-NL2 targets also led to an increase in the amount of high-frequency energy, more so for sentences spoken in Neutral and Sad conditions than in other emotion conditions. We conclude that amplitude processing by hearing aids is beneficial for audibility but potentially detrimental for emotion understanding.

The validation of a sound intensity imaging system for wall STC calculation, with leak detection

Abstract: This paper presents a comparison study of two methods that can be used for calculating the sound transmission classification (STC) of a sample wall in a test laboratory, as per ASTM E2249-2016. In both methods, the average sound pressure level within a reverberant room is taken, and the incident sound power on the wall in the source room is calculated. In the 1st method, the traditional method of E2249, an intensity probe is swept at a constant speed, across a set path, through a wire-frame grid specially constructed for the measurement. The sound power radiating from the whole wall is then calculated from the sound intensity, and the sound transmission loss is calculated by subtracting the radiated sound power of the wall from the incident sound power. Having calculated the TL, the STC can then be calculated via ASTM E413-2016. In the 2nd method, the sound intensity probe of the I-track sound intensity imaging system is swept across the wall surface at both an irregular speed and an irregular pattern. The sound power is instantly calculated by the software, as optical tracking of the probe means the spatial and temporal sampling of the sound intensity is made automatically. The sound power is then used to calculate the STC in the same manner as the traditional method. The paper presents the precision of the two methods (traditional vs imagery). Additionally, the paper will present a secondary benefit from the use of the imagery method not available to the traditional scan method; the ability to locate and rank acoustical weaknesses within the single surface scan.

Quantitative Differences in Highway Noise Levels due to Pavement Type: Impact on Modelling Future Noise Emissions

Abstract: An overview will be provided of three highway-noise models in use in Canada or the USA, the capacity of these models to accurately represent noise emissions from different pavements, and the constraints that are imposed in some jurisdictions that compromise the accuracy of modelling, particularly with forecasting of future noise levels after a project is built. Ideally, calculated noise levels will agree with measured levels of highway noise. The models to be reviewed include STAMSON 5.0, STAMINA 2.0, and the Traffic Noise Model (TNM). In some cases, the predictions are constrained through the mandated use of an ill-defined "average" pavement type that does not accurately represent either Portland Cement Concrete (PCC), Dense-Grade Asphalt Concrete (DGAC) or Open-Grade Asphalt Concrete (OGAC). As such, there are constraints on accuracy that occur when a modeller is obligated to assume that the pavement on a highway will be "average" as far as noise emissions are concerned. Detailed examples are provided that illustrate how specific geographic regions, such as American States, have documented the differences between pavements actually in use for a given State and a national average pavement type. The quantitative differences to be expected between PCC, DGAC, OGAC and "Average" pavements will be discussed.

Wind-Induced Noise of Architectural Perforated Plates

Abstract: Perforated plates are a popular architectural feature found on the outside faces of buildings. These plates are known to produce flow-induced noise when exposed to high winds. While this noise is generally broadband, for certain plate geometries, flow velocities, and angles of incidence, highly tonal noise is produced, the level of which can be much higher than that of the broadband noise. This is an irritant for inhabitants of the building and the surrounding area and may lead to costly retrofitting to eliminate the problem. Many studies can be found in the literature for flow over perforated plates at a parallel or perpendicular direction. However, the literature is very limited with regards to flow over perforated plates at oblique angles of incidence. For architectural applications, the direction of the wind is naturally unpredictable, so the effect of different angles of incidence is an important consideration. As a preliminary investigation, a simplified model of a perforated plate is used. The circular holes of a typical perforated plate are replaced by a series of long rectangular slats with an adjustable gap width between them. This simplified model is studied experimentally in a wind tunnel for various angles of incidence and flow velocities. The acoustic response is studied using microphone measurements, and flow visualization is done using particle image velocimetry. It is found that tonal noise is produced for angles of incidence of 5 to 30 degrees from parallel. The Strouhal number of these tones agrees well with those produced by a perforated plate. Outside of this range of angles, the noise is broadband. The flow visualization reveals that this tonal noise is caused by the periodic shedding and impingement of vortices on the downstream edge of the holes.

Improving ASTC Performance of As-built Wood-frame Double-shear Panel Wall Assemblies

Abstract: In wood-frame buildings, structural shear resistance in load-bearing walls is sometimes provided using OSB or plywood sheathing board directly applied on the wood framing. When these panels are used on both internal faces of a double-stud demising assembly with a drywall layer on each finished side, the sound transmission performance is significantly compromised by the air cavity resonance between the panels. This was the subject of a 2015 Acoustics Week presentation. As a follow-up, the mitigating effects of using a resilient mounting for the drywall are investigated from recent field measurements.

Surface Dipole Strength Generated by Cylindrical Struts

Abstract: The purpose of this work was to further establish the viability of the Causality Correlation Technique as a diagnostic tool for the treatment of noise problems. Acoustical dipole radiation can be generated by obstructing a subsonic flow with a rigid strut, if the strut exerts fluctuating forces on the fluid. Such forces would be the forces of reaction arising from the unsteadiness in the local flow and would form a distribution of acoustical dipole sources over the surface of the strut. For the experiments reported herein, a subsonic flow issues from a circular nozzle which is 3.8×10 -2 m in diameter. The ‘quiet’ air jet operates at an exit Mach number of .217. The exit velocity is 72 m/s and is approximately uniform over the exit plane. The cylinder model is stationed at the potential core of the jet the Reynolds number is 6.3×10 4 (based on cylinder diameter and exit velocity). The ‘Dipole Radiation Intensity (DRI)’ is a uniquely defined and measurable quantity that is intimately related to the classical dipole. The ‘spatial distribution’ of the DRI can be constructed on a surface using the Causality Correlation Technique (see Siddon). The ‘DRI distribution’ is constructed on the surface of the rigid cylindrical strut. A diagnosis is made of the aerodynamic noise generation mechanisms using the said distribution. The far field SPL originating from the surface exclusively is predicted from the integrated DRI distribution. For laminar incident flow the predicted SPL is (69.3 ± 2.3 dB). This may be compared with an overall SPL of (70.1±.5 dB) which was directly measured.

Sensory Integration from an Impossible Source: Perceiving Simulated Faces

Abstract: Recent research has shown that aero-tactile cues influence speech perception without the presence of an acoustic signal (Bicevskis, Derrick & Gick, 2016); when participants viewed a bilabial articulation that co-occurred with a puff of air felt on the skin, they were significantly more likely to perceive it as aspirated. These results and others (Gick & Derrick, 2009, etc.) suggest that this integration is relatively automatic, enough so that it does not require the physical presence of the source to arise. However, it may be that perceivers are willing to extend physical capabilities to these non-present sources because they are human and therefore possible sources of the aero-tactile cue. The current study examines whether aero-tactile information from an impossible source—a computer-animated face on a computer monitor—can affect perception of aspirated consonants. Sixteen native English speakers are shown an animated video of a computer-animated head performing a bilabial plosive but hear only babble noise through headphones. Some of the presentations are accompanied by a light, synchronous puff of air on the neck. They are asked to identify the syllable as either /ba/ or /pa/. Analysis of this two-alternative forced choice response task will be presented. Evidence of integration from an impossible source would support the idea that visual-tactile integration is an automatic process that occurs even in the absence of an interlocutor capable of producing the stimuli.

Methodological Trade-offs for Dual-purpose Phonetic Fieldwork

Abstract: Ultrasound overlay videos involve the superposition of ultrasound imaging of the tongue onto facial profile videos in order to serve as instructional materials (Abel et al., 2015). Bliss et al. (2016) used this technique to develop instructional and cultural materials for Indigenous communities by creating custom overlay videos of community members which highlight difficult sound contrasts in the languages for learners. Building on this work, this paper reports on the creation of this type of video for Han, a Dene/Athabaskan language of Eagle, Alaska and Dawson City, Yukon with 6-7 native speakers remaining. In the paper, we explore the challenges behind a new possibility of collecting the ultrasound data recorded for these instructional videos to serve a dual-purpose: instructional/cultural and linguistic/scientific. Some acoustic work has been done on Han (Manker 2012), but never articulatory. As Han is known for its large phonemic inventory, being tied for first as the language with the most affricates and containing a 5-6 way contrast in the coronal region, articulatory work on the language is of interest for phonetic and phonological theory. However, ultrasound work has quite strict methodological standards, which can be impractical to include in many field situations, such as precise head and probe stabilization, and fully controlled phonological environments and speaker groups. These standards by necessity and design could not be fully adhered to for the Han recordings. But, despite the methodological limitations involved in dual-purpose fieldwork, we argue that it is important to consider the possibility of drawing linguistic insights from data collected for instructional purposes. Otherwise, these insights simply wouldn’t exist as work with these communities is limited. References J. Abel, B. Allen, S. Burton, M. Kazama, M. Noguchi, A. Tsuda, N. Yamane, and B. Gick. Ultrasound-Enhanced Multimodal Approaches to Pronunciation Teaching and Learning. Canadian Acoustics , 43 (3). 124-125, 2015. Bliss, H., Burton, S., and Gick, B. (2016). Ultrasound Overlay Videos and Their Application in Indigenous Langauge Learning and Revitalization. Canadian Acoustics, 44 (3). Manker, Jonathan. (2012). An Acoustic Study of Stem Prominence in Han Athabaskan. Master’s thesis, University of Alaska Fairbanks.

Sociophonetic Research at the University of New Brunswick

Abstract: Research in our laboratory is situated at the interface of sociolinguistics and phonetics. Acoustic phonetic techniques are used to analyze regional, social and stylistic variation in the varieties of Acadian French spoken in New Brunswick. Studies analyze segmental features such as the consonant /r/ and the affrication of /t, d/; the study of prosodic features includes the application of rhythm metrics to prosodic units such as the accentual phrase.

The impact of dialect on the ability to understand speech-in-noise

Abstract: Difficulty understanding speech-in-noise (SIN) is one of the most commonly reported hearing issues for older adults. Thus, being able to accurately assess an individuals’ ability to understand SIN is of utmost importance. A number of standardized assessments have been developed to quantify this ability. These tests normally use pre-recorded speech as the target stimulus, and thus the language and dialect of each test cannot be easily modified. One issue that has received scant attention is how dialect impacts performance on a standardized SIN test. There is some evidence that it is more difficult to understand SIN in your native language, but not your native dialect. How this difficulty translates to a standardized, clinical SIN assessment is poorly understood. To address this issue, the QuickSIN was administered to a sample of native speakers of Newfoundland English. The QuickSIN is a standardized SIN assessment, and the target sentences are spoken in an English dialect that comes from the northern United States. The participants from Newfoundland performed outside the 95% CIs for the QuickSIN, despite having normal audiometric thresholds, which suggests that difficulties with dialect and not with hearing can contribute poorer performance on a SIN test in a clinical setting. The negative effect of dialect mismatch on clinical SIN assessments limits the ability for clinicians to accurately quantify SIN abilities in people whose native dialect does not match the test dialect.

Probabilistic approach to selecting a reasonable minimum sample of rooms for astm e-336 testing

Abstract: Faced with the potential of assessing compliance of 10,000 rooms within a new building complex, a statistical approach was developed to minimize the number of partitions to be ASTM E-336 tested. The building was constructed with various wall STCs ranging from STC 45 through STC 65+. Testing was designed primarily for wall constructions of STC 50 and STC 55 as they dominate the number of construction types. In addition to assessing compliance, the testing program was devised to find chronic deficiencies in the wall constructions during the build to result in immediate improvements in construction practices. Partitions to be tested were selected to include samples of different partition constructions, configurations, and sizes, as well as different room types, and were selected as randomly as possible spread evenly throughout the complex. The random element in selecting partitions is essential to assess workmanship of different construction crews, and is also important for maintaining the integrity of the statistical prediction process discussed below. A probability theory method was used to evaluate the results of field-measured ASTC versus the design STC requirements. This method includes a technique for assessing the results of remediating partitions that initially fail the criterion described above, and the subsequent remediation of similar partitions and adjustment of construction practices going forward. The statistical approach is designed to quantify the fraction of partitions that are rated a “Pass” for each round of testing and to compare the results to previous testing samples. The statistical analysis then provides a means of estimating the overall expected “Pass/Fail” rate for all partitions within the complex. The goal was to have a target % of total partitions to achieve the targeted ASTC rating. This level of performance is also achieved with a specific level of statistical confidence certainty. Testing of the complex was completed through an iterative process using the above approach until the set criteria were met.

Protection of Critical Assets from Construction Vibration - Field Tests, Prediction, and Control

Abstract: This paper presents the results from vibration testing and modelling conducted during the design of a major hospital complex expansion adjacent to a research facility. The expansion will include demolition of existing structures at the site and construction of several multi-storey buildings. Foundation works will include construction of raft slabs and installation of Franki piles. The research facility houses sensitive laboratory equipment as well as a vivarium at basement level. Protection of research assets is a major concern during demolition and construction as ground-borne vibrations can affect performance of sensitive equipment, disrupt long-term experiments (e.g., cell culture development), and negatively impact the health of the animals. As Vibration Consultants on the project, the authors were responsible for developing vibration control specifications to ensure appropriate protection of the research facility (and surrounding land uses) during demolition and construction. This included development of a construction vibration model to predict vibration levels during various demolition and construction activities. Model parameters were specified based on coordinated testing at the site, which included: the use of an excavator armed with a plate compactor to apply impacts and vibratory compaction to the ground at the surface and at a depth corresponding approximately to the depth of foundations for the new buildings; and, Installation of two Franki piles at locations corresponding to new building foundations. During the tests, vibration levels were measured in the research facility and at various surface-level setbacks from the sources to quantify ground transmission characteristics and response of the structure. The results of all tests and models were applied for the development of vibration control measures that included a construction vibration control specification and monitoring protocol.