Perceptual Thresholds for Vibration Transmitted to Road Cyclists.

OBJECTIVES: In this article, we seek to determine how sensitive road cyclists are to vertical vibration transmitted while riding a road bicycle and to propose metrics for the evaluation of dynamic comfort. BACKGROUND: Road cyclists are exposed to random-type excitation due to road roughness. Vibration transmitted affects dynamic comfort. But how sensitive are cyclists to vibration level? What are the best metrics to measure the amount of vibration transmitted to cyclists? Previous studies used sinusoidal excitation with participants on rigid seats and measured acceleration. METHODS: We use a psychophysical estimation of Just Noticeable Differences in Level (JNDL) for vertical vibration transmitted to cyclists on a road simulator. In Experiment 1, we estimate the JNDL for whole-body vibration using vertical excitation on both wheels simultaneously (20 male cyclists). In Experiment 2, we estimate the JNDL at two different points of contact by applying the same signal to only the hands or the buttocks (9 male cyclists). RESULTS: The JNDLs are expressed in terms of acceleration and power transmitted to the cyclist. We compare the JNDLs expressed with these 2 metrics and measured at different points of contact. CONCLUSION: Using these two metrics and at all points of contact, vibration magnitude needs to be reduced by at least 15%, for the change to be detectable by road cyclists. APPLICATION: A road bicycle needs to transmit at least 15% less vibration for male cyclists to detect an improvement in dynamic comfort. Dynamic bicycle comfort can be measured in terms of a new metric: power transmitted to the cyclist.

Situational and person-related factors influencing momentary and retrospective soundscape evaluations in day-to-day life.

Soundscape research draws on both experiments conducted in laboratory settings and studies in the field to explore peoples' perception and understanding of their acoustic environments. One opportunity to combine the strength of both approaches is the so-called Experience Sampling Method (ESM). This method was used to investigate the influence of situational and person-related variables on soundscape evaluations. Further, the relationship between momentary and retrospective soundscape judgments was explored. In the course of the 7-day ESM study, 32 participants were prompted ten times per day by a smartphone application to evaluate their soundscape and report on situational factors. Additionally, they performed summary retrospective judgments evaluating the whole of each day and their whole week. Upon completion, an exit interview probed personality traits (e.g., Big Five, information processing styles). Results revealed that both situational and person-related factors significantly contributed to the judgments of three soundscape dimensions (pleasantness, eventfulness, familiarity). Retrospective judgments of soundscape pleasantness were not only the average of the momentary judgments, but were also affected by the peak moment, the linear trend of the experience, and a person's mood while performing the judgment. Hence, the study provides valuable insights into the complex structure of momentary and retrospective soundscape evaluations.

Perceptual evaluation of violins: A psycholinguistic analysis of preference verbal descriptions by experienced musicians.

In this paper, how the notion of violin quality is conveyed in spontaneous verbalizations by experienced violinists during preference judgments is investigated. The aims of the study were to better understand how musicians conceptualize violin quality, what aspects of the sound and the playing experience are essential, and what associations are formed between perceptual evaluation and physical description. Upon comparing violins of varying make and age, players were interviewed about their preferences using open-ended questions. Concepts of violin quality were identified and categorized based on the syntactic and linguistic analysis of musicians' responses. While perceived variations in how a violin sounds and feels, and consequently conceptualization structures, rely on the variations in style and expertise of different violinists, the broader semantic categories emerging from sensory descriptions remain common across performers with diverse musical profiles, reflecting a shared perception of physical parameter patterns that allowed the development of a musician-driven framework for understanding how the dynamic behavior of a violin might relate to its perceived quality. Implications for timbre perception and the crossmodal audio-tactile sensation of sound in music performance are discussed.

Perceptual thresholds for non-ideal diffuse field reverberation.

The objective of this study is to understand listeners' sensitivity to directional variations in non-ideal diffuse field reverberation. An ABX discrimination test was conducted using a semi-spherical 28-loudspeaker array; perceptual thresholds were estimated by systematically varying the level of a segment of loudspeakers for lateral, height, and frontal conditions. The overall energy was held constant using a gain compensation scheme. When compared to an ideal diffuse field, the perceptual threshold for detection is -2.5 dB for the lateral condition, -6.8 dB for the height condition, and -3.2 dB for the frontal condition. Measurements of the experimental stimuli were analyzed using a Head and Torso Simulator as well as with opposing cardioid microphones aligned on the three Cartesian axes. Additionally, opposing cardioid measurements made in an acoustic space demonstrate that level differences corresponding to the perceptual thresholds can be found in practice. These results suggest that non-ideal diffuse field reverberation may be a previously unrecognized component of spatial impression.

Perceptual thresholds for realistic double-slope decay reverberation in large coupled spaces.

Reverberation highly influences sound perception in enclosed spaces. The reverberation time (RT) metric, used to quantify reverberation in single volumes, is inappropriate for coupled spaces characterized by non-exponential double-slope energy decays. Previous research on reverberation perception of double-slope decays has been predominantly based on varying basic impulse response characteristics such as decay times corresponding to reverberation times of individual volumes presented as independent variables. Alternatively, several studies have employed geometrical room acoustic software simulations to generate collections of responses while varying architectural parameters such as coupling area and room volumes. To avoid issues related to geometrical acoustics simulations, such as position dependence and limitations of some software to properly simulate coupled volume behavior, this study examines perception of the variability of reverberation typical of a physical coupled volume system. Employing an established statistical model, the control parameter of coupling area aperture which acoustically connects the volumes serves as the independent variable. Two listening tests were conducted to determine perceptual thresholds using an ABX discrimination task. The range of tested values corresponded to physically realizable variations. Just noticeable differences (JNDs) were derived with an average JND of ≈ 10% variation of the coupling aperture. No significant differences were found between different musical excerpts.

Do whole-body vibrations affect spatial hearing?

To assist the human operator, modern auditory interfaces increasingly rely on sound spatialisation to display auditory information and warning signals. However, we often operate in environments that apply vibrations to the whole body, e.g. when driving a vehicle. Here, we report three experiments investigating the effect of sinusoidal vibrations along the vertical axis on spatial hearing. The first was a free-field, narrow-band noise localisation experiment with 5- Hz vibration at 0.88 ms(-2). The other experiments used headphone-based sound lateralisation tasks. Experiment 2 investigated the effect of vibration frequency (4 vs. 8 Hz) at two different magnitudes (0.83 vs. 1.65 ms(-2)) on a left-right discrimination one-interval forced-choice task. Experiment 3 assessed the effect on a two-interval forced-choice location discrimination task with respect to the central and two peripheral reference locations. In spite of the broad range of methods, none of the experiments show a reliable effect of whole-body vibrations on localisation performance. PRACTITIONER SUMMARY: We report three experiments that used both free-field localisation and headphone lateralisation tasks to assess their sensitivity to whole-body vibrations at low frequencies. None of the experiments show a reliable effect of either frequency or magnitude of whole-body vibrations on localisation performance.

Current approaches to planning (with) sound.

While sound plays a critical role in our experience of the built environment, professionals feel ill-equipped to design and plan with sound in mind. Through a document analysis for 22 planning projects from Quebec, we aim to better understand how sound considerations are integrated into planning in practice. We identify and characterize the observed strategies and propose a typology of sound approaches in planning along two axes related to 1) the integration of the project into the pre-existing sound environment (from continuity to disruption) and 2) the nature and extent of sound considerations (from minimal to composite). This mapping revealed four main approaches to planning with sound, namely insufficient, sufficient, necessary, and extensive. The analysis further highlights a disconnect between planning and sound considerations, partly related to the abstract nature of planning considerations that exert an inherent but rarely acknowledged influence on sound. This disconnect is clearly visible at a tipping point between (flexible but vague) planning considerations and (concrete but technical) sound considerations when projects tend toward a more difficult integration into the pre-existing environment. We conclude with suggestions on how to move toward composite approaches to better integrate sound into planning.

Investigating sonic injustice: A review of published research.

Sound has been researched as either an environmental pollutant (noise) with detrimental health effects or an environmental resource with beneficial outcomes for well-being. We define sonic injustice as unjust inequalities in both noise exposure and access to high-quality, beneficial sound environments. We performed a comparative analysis of 34 peer-reviewed studies on sonic injustice. These studies were from Europe, North America, Accra and Hong Kong. We found suggestive evidence of a social inequality in noise exposure, particularly for low income and racial/ethnic groups. In contrast, children were often associated with an underexposure to noise. We did not find any studies on inequalities in access to beneficial sound environments, except for one study on quiet areas. As well, this review identifies trends in European and North American studies; discusses causal mechanisms for sonic inequalities; and presents avenues for future investigations into sonic injustice.

Humans sense by touch the location of objects that roll in handheld containers.

Humans use active touch to gain behaviourally relevant information from their environment, including information about contained objects. Although most common, the perceptual basis of interacting with containers remains largely unexplored. The first aim of this study was to determine how accurately people can sense, by touch only, the location of a contained rolling object. Experiment 1 used tubes containing physical balls and demonstrated a considerable degree of accuracy in estimating the rolled distance. The second aim was to identify the relative effectiveness of the various available physical cues. Experiment 2 employed virtual reality technology to present, in isolation and in various combinations, the constituent haptic cues produced by a rolling ball, which are, the mechanical noise during rolling, the jolts from an impact with an internal wall, and the intensity and timing of the jolts resulting from elastic bounces. The rolling noise was of primary importance to the perceptual estimation task suggesting that the implementation of the laws of motion is based on an analysis of the ball's movement velocity. Although estimates became more accurate when the rolling and impact cues were combined, they were not necessarily more precise. The presence of elastic bounces did not affect performance.

Assessing the ecological validity of soundscape reproduction in different laboratory settings.

The ever-growing body of soundscape research includes studies conducted both in everyday life environments and in laboratory settings. Yet, laboratory settings differ from in-situ and therefore may elicit different perceptions. The present study explores the ecological validity of soundscape reproduction in the laboratory using first-order Ambisonics and of different modes of questionnaire administration. Furthermore, it investigates the influence of the contextual factors of time of day, day of the week, and location on site on soundscape evaluations in situ and in the laboratory, based on the Swedish Soundscape Quality Protocol. We first tested measurement invariance between the computer-based and pen-and-paper administration of the soundscape questionnaire. We then investigated the influence of the above-mentioned contextual factors on soundscape evaluations, as well as the effect of stimuli selection in the laboratory. The analyses confirmed the underlying dimensions of proposed soundscape assessment questionnaires, confirmed metric invariance between computer and pen-and-paper, and revealed significant influences of time, day, and location on soundscape scales. This research represents a critical step in rigorously assessing soundscape evaluations in the laboratory and establishes solid evidence for the use of both in situ and laboratory soundscape studies.

Effect of Hearing Protection Use on Pianists' Performance and Experience: Comparing Foam and Musician Earplugs.

Professional musicians are often exposed to high noise levels and thus face the risk of noise-induced hearing loss. Yet, adoption rates for hearing protection among musicians are low. Previous surveys indicate that the chief concern is the effect of hearing protection use on performance. However, few studies have investigated actual changes in performance when wearing hearing protection. We report an experiment investigating differences in pianists' performance and experience with and without hearing protection. We compare the effect of foam earplugs and musician earplugs, designed to preserve sound quality with a flat frequency response. The analysis revealed that participants performed overall more loudly with the foam earplugs than with the musician earplugs, and in turn performances with the musician earplugs were louder than the open condition, indicating a compensatory effect. However, this effect was stronger for novel excerpts than for familiar excerpts. No effect was observed on dynamic range. Furthermore, we observed an acclimatization effect, whereby the effect of hearing protection use, observed on the first performance, decreased on the second performance. In terms of experience, participants reported changes in coloration, difficulties gauging dynamics and articulation, and increased effort required when performing with hearing protection. These effects were more pronounced when wearing the foam earplugs, and the participants reported finding the musician earplugs more comfortable to wear and play with. In conclusion, hearing protection use affects pianists' performance particularly in terms of dynamics and their experience more so in terms of coloration. But the effects are less marked for familiar pieces and after repetition, suggesting that pianists can quickly adjust their playing when playing familiar pieces with hearing protection.

Quieted City Sounds during the COVID-19 Pandemic in Montreal.

This paper investigates the transformation of urban sound environments during the COVID-19 pandemic in Montreal, Canada. We report on comparisons of sound environments in three sites, before, during, and after the lockdown. The project is conducted in collaboration with the Montreal festival district (Quartier des Spectacles) as part of the Sounds in the City partnership. The analyses rely on continuous acoustic monitoring of three sites. The comparisons are presented in terms of (1) energetic acoustic indicators over different periods of time (Lden, Ld, Le, Ln), (2) statistical acoustic indicators (L10, L90), and (3) hourly, daily, and weekly profiles of sound levels throughout the day. Preliminary analyses reveal sound level reductions on the order of 6-7 dB(A) during lockdown, with differences more or less marked across sites and times of the day. After lockdown, sound levels gradually increased following an incremental relaxation of confinement. Within four weeks, sound levels measurements nearly reached the pre-COVID-19 levels despite a reduced number of pedestrian activities. Long-term measurements suggest a 'new normal' that is not quite as loud without festival activities, but that is also not characterizable as quiet. The study supports reframing debates about noise control and noise management of festival areas to also consider the sounds of such areas when festival sounds are not present.

Comparison of Road Noise Policies across Australia, Europe, and North America.

Developing innovative noise policies that build on international best practices is difficult when policies around the world differ along many dimensions, ranging from different sources covered to different levels of governance involved. This is particularly critical in the context of road traffic, identified as one of the main culprits leading to noise-associated complaints and health issues. In this article, we document the wide range of specifications observed in road traffic policies and propose a methodology to compare noise limits across noise policies. First, we present the responsibilities of administrative governments according to the scope (e.g., emission vs. exposure). Second, we compare noise limits by scope and geographic areas by separating acoustic indicators (overall and event indicators). Third, we convert overall outdoor noise limits into a common basis using the method described by Brink and his associates (2018) and compare them with the World Health Organization (WHO)'s recommendations (2018). Finally, measurement protocols are also compared across outdoor noise policies. This paper shows that road noise is managed at several administrative levels using approaches that are either centralized or decentralized. We also observed disparities in the associated noise limits across geographic areas. The converted outdoor noise limits generally exceeded the WHO's recommendations (2018). Finally, this paper outlines how outdoor measurement protocols vary across geographic areas. However, similarities were identified between state and provincial noise policies within the same country.

Upper limits of auditory rotational motion perception.

Three experiments are reported, which investigated the auditory velocity thresholds beyond which listeners are no longer able to perceptually resolve a smooth circular trajectory. These thresholds were measured for band-limited noises, white noise, and harmonic sounds (HS), and in different acoustical environments. Experiments 1 and 2 were conducted in an acoustically dry laboratory. Observed thresholds varied as a function of stimulus type and spectral content. Thresholds for band-limited noises were unaffected by center frequency and equal to that of white noise. For HS, however, thresholds decreased as the fundamental frequency of the stimulus increased. The third experiment was a replication of the second in a reverberant concert hall, which produced qualitatively similar results except that thresholds were significantly higher than in the acoustically dry laboratory.

A Tale of Three Misters: The Effect of Water Features on Soundscape Assessments in a Montreal Public Space.

The acoustic environments of small, central urban parks are often dominated by traffic sounds. Water sounds can be used to mitigate the negative impacts of unwanted sounds through masking. Studies comparing the effects of different water sounds are typically conducted using recordings in laboratory settings where ecological validity is limited. An urban redesign project in Montreal took the innovative approach of trying three sequential temporary designs of a new public square, each of which included a distinct water feature that produced a lightly-audible mist. Here we report on a field experiment evaluating the effect of the water feature in each of the three designs. Respondents (n = 274) evaluated their experience with the three different designs using questionnaires including soundscape (SSQP) and restorativeness scales, and perceived loudness. The results indicate a significant interaction effect between the water feature and the design of the space, particularly on ratings of chaotic and loud. While two water feature designs had an overall "positive" effect (i.e., less loud and chaotic) on soundscape assessment, the third water feature design produced the opposite effect. These findings hold even after accounting for ambient temperature. This opportunity to test multiple water features in the same space revealed that water features do not automatically improve soundscape assessments. The visual design, function of the space and environmental conditions should be carefully considered and calls for more field studies. We discuss consequences and considerations for the use of water features in public spaces as well as the implications in terms of ecological validity of soundscape studies.

Auditory motion perception emerges from successive sound localizations integrated over time.

Humans rely on auditory information to estimate the path of moving sound sources. But unlike in vision, the existence of motion-sensitive mechanisms in audition is still open to debate. Psychophysical studies indicate that auditory motion perception emerges from successive localization, but existing models fail to predict experimental results. However, these models do not account for any temporal integration. We propose a new model tracking motion using successive localization snapshots but integrated over time. This model is derived from psychophysical experiments on the upper limit for circular auditory motion perception (UL), defined as the speed above which humans no longer identify the direction of sounds spinning around them. Our model predicts ULs measured with different stimuli using solely static localization cues. The temporal integration blurs these localization cues rendering them unreliable at high speeds, which results in the UL. Our findings indicate that auditory motion perception does not require motion-sensitive mechanisms.

Soundtracking the Public Space: Outcomes of the Musikiosk Soundscape Intervention.

Decades of research support the idea that striving for lower sound levels is the cornerstone of protecting urban public health. Growing insight on urban soundscapes, however, highlights a more complex role of sound in public spaces, mediated by context, and the potential of soundscape interventions to contribute to the urban experience. We discuss Musikiosk, an unsupervised installation allowing users to play audio content from their own devices over publicly provided speakers. Deployed in the gazebo of a pocket park in Montreal (Parc du Portugal), in the summer of 2015, its effects over the quality of the public urban experience of park users were researched using a mixed methods approach, combining questionnaires, interviews, behavioral observations, and acoustic monitoring, as well as public outreach activities. An integrated analysis of results revealed positive outcomes both at the individual level (in terms of soundscape evaluations and mood benefits) and at the social level (in terms of increased interaction and lingering behaviors). The park was perceived as more pleasant and convivial for both users and non-users, and the perceived soundscape calmness and appropriateness were not affected. Musikiosk animated an underused section of the park without displacing existing users while promoting increased interaction and sharing, particularly of music. It also led to a strategy for interacting with both residents and city decision-makers on matters related to urban sound.

Exploring the Validity of the Perceived Restorativeness Soundscape Scale: A Psycholinguistic Approach.

Soundscapes affect people's health and well-being and contribute to the perception of environments as restorative. This paper continues the validation process of a previously developed Perceived Restorativeness Soundscape Scale (PRSS). The study takes a novel methodological approach to explore the PRSS face and construct validity by examining the qualitative reasons for participants' numerical responses to the PRSS items. The structure and framing of items are first examined, to produce 44 items which are assessed on a seven-point Likert agreement scale, followed by a free format justification. Ten English speaking participants completed the PRSS interpretation questionnaire in two cafes in Montréal, Canada. Interpretation of participant free format responses led to six themes, which related to either the individual (personal attributes, personal outcomes), the environment (physical environment attributes, soundscape design) or an interaction of the two (behavior setting, normality, and typicality). The themes are discussed in relation to each Attention Restoration Theory (ART) component, namely Fascination, Being-Away, Compatibility, and Extent. The paper concludes by discussing the face and construct validity of the PRSS, as well as the wider methodological and theoretical implications for soundscape and attention restoration research, including the terminology importance in items measuring ART components and the value of all four components in assessing perceived restorativeness.

Categorization of environmental sounds.

This paper investigates the way in which people categorize environmental sounds in their everyday lives. Previous research has shown that isolated environmental sounds are categorized on the basis of high-level semantic features when the sounds can be attributed to specific sound sources. However, in the presence of numerous sound sources, as occur in most real-world situations, the process of source identification is often hindered. In the present study, a free categorization task with open-ended verbal descriptions was used to investigate auditory categories for environmental sounds in complex real-world sonic environments. Two main categories emerged from the free-sort, reflecting the absence or presence of human activity in relation to hedonic judgments. At a subordinate level, subcategories were mediated by the participant's reported interactions with the environment through socialized activities. The spontaneous verbal descriptors collected were successful in discriminating categories. These findings indicate that complex environmental sounds are processed and categorized as meaningful events providing relevant information about the environment. The relevance of situational factors in categorization and the notion of auditory category in its relation to linguistic labeling are then discussed.