Acoustical Environment Studies in the Modern Urban University Campuses

The quality of the acoustic environments at Xi’an Jiatong-Liverpool University (XJTLU) and Soochow University (Dushuhu Campus, SUDC) in Suzhou City were investigated in the present work through real-time noise level measurements and questionnaire surveys. Before commencing the measurements and surveys, these two campuses’ sound sources were summarized and classified into four categories through on-site observation: human-made, machinery, living creatures, and natural physical sounds. For the zones near the main traffic road, with a high volume of crowds and surrounded by a park, sound from road vehicles, humans talking, and birds/insects were selected by the interviewees as the major sound sources, respectively. Only zone 3 (near to a park) at XJTLU could be classified as A zone (noise level < 55 dBA) with an excellent quality acoustical environment. All other zones had either good or average quality acoustical environments, except zone 1 (near to main traffic road) at XJTLU, with a fair-quality acoustical environment.

Continuous dynamics in behavior reveal perceptual nonlinearities aid speech categorization in noise

Spoken language comprehension requires listeners map continuous features of the speech signal to discrete category labels. Categories are however malleable to surrounding context; listeners’ percept can dynamically shift depending on the sequencing of adjacent stimuli resulting in a warping of the heard phonetic category (i.e., hysteresis). Here, we investigated whether such perceptual nonlinearities—which amplify categorical hearing—might further aid speech processing in noise-degraded listening scenarios. We measured continuous dynamics in perception and category judgments of an acoustic-phonetic vowel gradient via mouse tracking. Tokens were presented in serial vs. random orders to induce more/less perceptual warping while listeners categorized continua in clean and noise conditions. Listeners’ responses were faster and their mouse trajectories closer to the ultimate behavioral selection (marked visually on the screen) in serial vs. random order, suggesting increased perceptual attraction to category exemplars. Interestingly, order effects emerged earlier and persisted later in the trial time course when categorizing speech in noise. These data describe a new functional benefit of perceptual nonlinearities to speech perception yet undocumented: warping strengthens the behavioral attraction to relevant speech categories while simultaneously assisting perception in degraded acoustic environments.

Towards Child-Appropriate Virtual Acoustic Environments: A Database of High-Resolution HRTF Measurements and 3D-Scans of Children

Head-related transfer functions (HRTFs) play a significant role in modern acoustic experiment designs in the auralization of 3-dimensional virtual acoustic environments. This technique enables us to create close to real-life situations including room-acoustic effects, background noise and multiple sources in a controlled laboratory environment. While adult HRTF databases are widely available to the research community, datasets of children are not. To fill this gap, children aged 5–10 years old were recruited among 1st and 2nd year primary school children in Aachen, Germany. Their HRTFs were measured in the hemi-anechoic chamber with a 5-degree × 5-degree resolution. Special care was taken to reduce artifacts from motion during the measurements by means of fast measurement routines. To complement the HRTF measurements with the anthropometric data needed for individualization methods, a high-resolution 3D-scan of the head and upper torso of each participant was recorded. The HRTF measurement took around 3 min. The children’s head movement during that time was larger compared to adult participants in comparable experiments but was generally kept within 5 degrees of rotary and 1 cm of translatory motion. Adult participants only exhibit this range of motion in longer duration measurements. A comparison of the HRTF measurements to the KEMAR artificial head shows that it is not representative of an average child HRTF. Difference can be seen in both the spectrum and in the interaural time delay (ITD) with differences of 70 μs on average and a maximum difference of 138 μs. For both spectrum and ITD, the KEMAR more closely resembles the 95th percentile of range of children’s data. This warrants a closer look at using child specific HRTFs in the binaural presentation of virtual acoustic environments in the future.

Assessing Ecologically Valid Methods of Auditory Feedback Measurement in Individuals With Typical Speech

Purpose: Auditory feedback is thought to contribute to the online control of speech production. Yet, the standard method of estimating auditory feedback control (i.e., reflexive responses to auditory–motor perturbations), although sound, requires specialized instrumentation, meticulous calibration, unnatural tasks, and specific acoustic environments. The purpose of this study was to explore more ecologically valid features of speech production to determine their relationships with auditory feedback mechanisms. Method: Two previously proposed measures of within-utterance variability (centering and baseline variability) were compared with reflexive response magnitudes in 30 adults with typical speech. These three measures were estimated for both the laryngeal and articulatory subsystems of speech. Results: Regardless of the speech subsystem, neither centering nor baseline variability was shown to be related to reflexive response magnitudes. Likewise, no relationships were found between centering and baseline variability. Conclusions: Despite previous suggestions that centering and baseline variability may be related to auditory feedback mechanisms, this study did not support these assertions. However, the detection of such relationships may have required a larger degree of variability in responses, relative to that found in those with typical speech. Future research on these relationships is warranted in populations with more heterogeneous responses, such as children or clinical populations. Supplemental Material https://doi.org/10.23641/asha.17330546

The Living Barrier: Residential architecture acting as a noise barrier near railway corridors

<p>As urban regions increase in population and density, the need for quietness and spaces of relative calm becomes important to inhabitants’ physiological and psychological health and wellbeing. Noises, and the sounds that create them, are treated as a by-product of urban densification and the advancement of technology. This led to uncontrolled and incidental acoustic environments around notable points of urban densification. Each sound adds together in the acoustic environment to create a composition that is labelled collectively as noise. Those in the professions of planning and designing these urban environments have a responsibility to become the composers of the grand aural experience that is the worldly soundscape. In response to this design problem, this portfolio explored how architecture can be designed to enable this sustainable densification of noisy urban environments. It proposed the incorporation of psychoacoustics and R. Murray Schafer’s soundscape philosophy (and ongoing related research) into acoustic design. By understanding the complex creation of the aural experience, this portfolio investigated whether the key to living healthily and sustainably in an inevitably sound-filled urban environment laid in the design of soundscape as a perceptual construct. The investigation translated relevant literature into broad explorations of soundscape design elements at a variety of architectural scales. Using soundscape principles in a design process produced a strong architectural proposition that could solve both densification and acoustic problems. This had widespread and profound implications on architectural design practices. The portfolio therefore prompts further explorations into soundscape design for other architectural problems and applications.</p>

The Living Barrier: Residential architecture acting as a noise barrier near railway corridors

<p>As urban regions increase in population and density, the need for quietness and spaces of relative calm becomes important to inhabitants’ physiological and psychological health and wellbeing. Noises, and the sounds that create them, are treated as a by-product of urban densification and the advancement of technology. This led to uncontrolled and incidental acoustic environments around notable points of urban densification. Each sound adds together in the acoustic environment to create a composition that is labelled collectively as noise. Those in the professions of planning and designing these urban environments have a responsibility to become the composers of the grand aural experience that is the worldly soundscape. In response to this design problem, this portfolio explored how architecture can be designed to enable this sustainable densification of noisy urban environments. It proposed the incorporation of psychoacoustics and R. Murray Schafer’s soundscape philosophy (and ongoing related research) into acoustic design. By understanding the complex creation of the aural experience, this portfolio investigated whether the key to living healthily and sustainably in an inevitably sound-filled urban environment laid in the design of soundscape as a perceptual construct. The investigation translated relevant literature into broad explorations of soundscape design elements at a variety of architectural scales. Using soundscape principles in a design process produced a strong architectural proposition that could solve both densification and acoustic problems. This had widespread and profound implications on architectural design practices. The portfolio therefore prompts further explorations into soundscape design for other architectural problems and applications.</p>

Subjective Experience of Speech Depending on the Acoustic Treatment in an Ordinary Room

In environments such as classrooms and offices, complex tasks are performed. A satisfactory acoustic environment is critical for the performance of such tasks. To ensure a good acoustic environment, the right acoustic treatment must be used. The relation between different room acoustic treatments and how they affect speech perception in these types of rooms is not yet fully understood. In this study, speech perception was evaluated for three different configurations using absorbers and diffusers. Twenty-nine participants reported on their subjective experience of speech in respect of different configurations in different positions in a room. They judged sound quality and attributes related to speech perception. In addition, the jury members ranked the different acoustic environments. The subjective experience was related to the different room acoustic treatments and the room acoustic parameters of speech clarity, reverberation time and sound strength. It was found that people, on average, rated treatments with a high degree of absorption as best. This configuration had the highest speech clarity value and lowest values for reverberation time and sound strength. The perceived sound quality could be correlated to speech clarity, while attributes related to speech perception had the strongest association with reverberation time.