Natural Sounds Research Articles

“To Be, or Not to Be”: Critical Assessment of the Use of α-Acoustic Diversity Indices to Evaluate the Richness and Abundance of Coastal Marine Fish Sounds

Passive acoustic monitoring can be used to assess the presence of vocal species. Automatic estimation of such information is critical for allowing diversity monitoring over long time spans. Among the existing tools, α-acoustic indices were originally designed to assess the richness/complexity of terrestrial soundscapes. However, their use in marine environments is impacted by fundamental differences between terrestrial and marine soundscapes. The aim of this study was to determine how they vary depending on the abundance and sound type richness of fish sounds. Fourteen indices used in terrestrial environments were tested. The indices were calculated for files from three sources: a controlled environment (playback of artificial tracks in a pool), in situ playbacks (playback of natural soundscapes), and a natural environment (only natural sounds). The controlled experiment showed that some indices were correlated with the sound abundance but not with the sound type richness, implying that they are not capable of distinguishing the different types of fish sounds. In the in situ playbacks, the indices were not able to capture differences, both in terms of the sound abundance and sound type diversity. In the natural environment, there was no correlation between most of the indices and the abundance of sounds. They were impacted by mass phenomena of biological sounds (e.g., the Pomacentridae sounds in shallow reefs) that cannot inform on fish acoustic diversity. Indices are appropriate when soundscapes are divided into bands. In contrast to terrestrial environments, frequency bands in coastal marine soundscapes do not provide ecologically relevant information on diversity. Overall, indices do not appear to be suitable for inferring marine fish sound diversity.

Effects of soundscape on Chinese children's social interaction measured by self-reported behavioral expectations

Soundscape research has achieved some progress in enhancing the quality of urban space to support mixed uses. However, there is little evidence of promoting individual development and social relationship. Accordingly, the present study investigated the effects of soundscape on children's social interaction measured by self-reported behavioral expectations (Interaction, Nonparticipation, Avoiding) in the laboratory settings. Environmental exposure conditions were eight soundscape stimuli and one control condition (No sound), presented alongside visual recordings from a schoolyard or an urban park. Results showed that the soundscapes had significant effects on children's behavioral expectations and these effects did not differ significantly between the schoolyard and the urban park. Compared to No sound, Children's sounds and Nature sounds predisposed children to interactions, while Animal sounds and Classical music elevated children's intention to stay alone in the environment. Comparisons to the control group aside, correspondence analyses suggested the relationships between various soundscapes and behavioral expectations categories: Human movement sounds, Children's sounds, Adults' sounds, and Nature sounds were associated with Interaction; Animal sounds and Classical music were associated with Nonparticipation; Motorized transport sounds and Electro-mechanical sounds were associated with Avoiding. These findings on children's behavioral expectations indicate that the soundscape can influence children's decisions about contact and interaction with others in the environment, thereby fostering or impeding children from establishing and maintaining social relationships.

Nature Sounds for Stress Recovery and Healthy Eating: A Lab Experiment Differentiating Water and Bird Sound

This lab-based study tested whether nature sounds can lead to less stress reactivity, better stress recovery, less stress-induced eating and healthy food choice stimulation, while differentiating between bird and water sounds. Before (5 min) and after (8 min) the Trier Social Stress Test, 59 participants (47% men, 18–30 years) were exposed to one of three soundtracks: birds, streaming water, or wind as control. Group differences were tested on negative affect, salivary cortisol, heart rate variability, hunger, food craving, snack intake and influence expectations. Both bird and water sounds led to better cortisol recovery (not reactivity) and were reported to be more stress-reducing than wind only. The recovery effect was highest for water sounds. No differential sound effects were found for the food variables. The results confirm the potential implementation of bird and water sounds for stress restoration but future research should test the effects (especially on diet) in real-life settings.

The correlation of the voice and the piano parts in the vocal music of Schubert’s predecessors

This article analyzes the historical and cultural background of F. Schubert’s achievements in the field of chamber vocal music, in particular, in correlation with the vocal and piano parts. We are talking about the fact that the basis of Schubert’s Lied are the traditions of German and Austrian folk songs, the work of minnesingers, meistersingers, predecessor composers. Reliance on folklore determines the intonation, the rhythmic and structural patterns of Schubert’s songs. The influence of the masters of minnesang and meistersang is felt in the harmony and composition logic of the Austrian genius. The legacy of Mozart and Beethoven is especially close to the romantic achievements of Schubert. In the chamber-vocal music of these Viennese classics are used different types of correlation between the vocal and instrumental music scores: accompaniment prevails according to the principles of the general bass, but there are already some examples of relative independence of the music score ensemble. There appear instrumental introductions, conclusions, interludes. The texture of the piano part is diversified according to the types of presentation, and contains an imitation of the sounds of nature.

An Optimality-Theoretic Analysis of Some Phonological Errors Produced by Saudi Female Learners of the English Language

Purpose. The purpose of this study was to investigate the phonological errors associated with consonant and vowel pronunciation made by Saudi learners of the English language in light of the optimality hypothesis. In addition, transfer and contrastive analysis hypotheses are discussed, which justify why Saudi English language learners make phonological errors. Methods. Thirty Saudi female students in their first semester in the English language department at Qassim University were randomly selected. They were examined on their pronunciation of over 30 words from a list of twenty sentences. Each participant was individually recorded using a sensitive microphone, and all recordings were transcribed using IPA symbols and compared to the English transcription to identify the correct and incorrect pronunciation. Each participant filled out a consent form before to having their pronunciation recorded. Results. The majority of errors committed by Saudi English learners are attributable to the substitution of foreign sounds with the closest native sounds. In addition, Saudi English learners tend to add a glottal stop to non-onset syllables and insert a vowel to break clusters of three or more obstruent consonants. This finding is due to the fact that their native language is an onset language and lacks clusters of three or more obstruent consonants. The descriptive tables in addition to the Pareto charts of these errors are provided. Conclusions. Overall, results from this study support optimality theory, transfer, and contrastive analysis hypotheses. Moreover, this study contributes to the growing literature on the investigation of phonological errors produced by Arab learners of English, particularly Saudi learners. This study proposes that Saudi English learners listen attentively to English native speakers to correct phonological errors. In addition, Saudi English learners should record their pronunciation during discussions and replay them in order to identify their mistakes and avoid them in the future.

Intermediate acoustic-to-semantic representations link behavioral and neural responses to natural sounds

Recognizing sounds implicates the cerebral transformation of input waveforms into semantic representations. Although past research identified the superior temporal gyrus (STG) as a crucial cortical region, the computational fingerprint of these cerebral transformations remains poorly characterized. Here, we exploit a model comparison framework and contrasted the ability of acoustic, semantic (continuous and categorical) and sound-to-event deep neural network representation models to predict perceived sound dissimilarity and 7 T human auditory cortex functional magnetic resonance imaging responses. We confirm that spectrotemporal modulations predict early auditory cortex (Heschl’s gyrus) responses, and that auditory dimensions (for example, loudness, periodicity) predict STG responses and perceived dissimilarity. Sound-to-event deep neural networks predict Heschl’s gyrus responses similar to acoustic models but, notably, they outperform all competing models at predicting both STG responses and perceived dissimilarity. Our findings indicate that STG entails intermediate acoustic-to-semantic sound representations that neither acoustic nor semantic models can account for. These representations are compositional in nature and relevant to behavior.

Exploring the role of soundscape in restorative experience: A pilot study from children's perspective.

Indoor and outdoor noise is renowned for its ability to negatively affect children's health and performance. However, the possible restorative benefits of everyday soundscapes in children are still poorly understood. This study aimed to explore the role of everyday soundscapes in children's restorative experiences in frequented indoor (classroom) and outdoor (urban park) environments. In stage one, 335 children (7-12 years old) were interviewed using a questionnaire survey to investigate their restoration needs, restorative experience, and potential restorative sounds. In stage two, 61 children participated in a laboratory study to assess the perceived restorativeness of different soundscapes, which were combinations of potential restorative sounds and background noise, under signal-to-noise ratios (SNRs) from -5 to 15 dB. The findings denoted that the children's need for restoration increased with age significantly. Younger children reported that the role of the sound environment was more important in their classroom experiences than in urban parks. Although the types of music displayed in surveyed parks were generally not preferred by the children, music was assessed as the most restorative sound in the laboratory study. Additionally, natural sounds were perceived to be more restorative than background noise in the context. In particular, birdsong showed more restorativeness in the classroom context, whereas fountain sounds showed more restorativeness in the park context. Additionally, an SNR of at least 5 dB is desirable when considering the restorative experiences of children in classrooms and urban parks.

Early Childhood in the Era of Post-humanism: Lending an Ear to Nature

Parents, or pre-school educators in early childhood education, focus on assisting children to attain the highest possible pre-numeracy and pre-literacy skills in an attempt to give children a better academic foundation. Children are presented with technology, for example, in the form of a tablet, that act as baby-sitters even before they can speak properly, and this has largely deafened them to the sounds of nature. Sounds of man and machine are the only ones most children will be exposed to, due to their living in cities with few natural spaces. Children are not taken into nature to experience it and get to know the sounds of the bio-network, of which they are an integral part. Rural children may have a better chance to get to know, respect and cherish nature, due to their context, but their guides - parents and/or communities - have sunken into their own disregard for their environment. It is only when children are taught to listen to and appreciate nature that they will be enabled to begin moving back to being ‘mensch’ where the focus, ironically, moves away from the human and focuses instead on creating an equilibrium between humanity and nature, rather than stripping the planet of its natural resources through harmful practices. This empirical research explored the literature to highlight the significance of listening as a mode of developing an appreciation of and caring for nature. Attuning children of the post-humanist era to their natural environment through listening will encourage them to understand their function as part of nature, and assist in the restoration of the planet.

Acoustic information masking effects of natural sounds on traffic noise based on psychological health in open urban spaces.

The use of existing resources, such as natural sounds, to promote the mental health of citizens is an area of research that is receiving increasing attention. This research contributes to existing knowledge by combining a field psychological walk method and an experimental acoustic control method to compare the acoustic information masking effects of water and birdsong sounds on traffic noise based on the psychological health responses of 30 participants to such effects. The influence of traffic noise and contextual sounds on the psychological health of participants identified the potential of natural sounds in the acoustic information masking of traffic noise. Furthermore, it was found that 65.0 dBA water sounds did not mask 60.0 dBA traffic noises. However, 45.0 dBA birdsong sounds did mask it, but this effect was not significant. Additionally, contextual factors with and without crowd activity sounds were not significant in influencing psychological health through birdsong. This study contributes to public health cost savings. It may also guide the development of new ideas and methods for configuring open urban spaces according to public health needs.

The Poetic Music of Wallace Stevens by Bart Eeckhout and Lisa Goldfarb

Reviewed by: The Poetic Music of Wallace Stevens by Bart Eeckhout and Lisa Goldfarb Langdon Hammer The Poetic Music of Wallace Stevens. By Bart Eeckhout and Lisa Goldfarb. Cham, Switzerland: Palgrave Macmillan, 2022. If a poem is like a picture, it is like an object, with the manifest presence of a thing. To say a poem is like music is to say it is like a process or performance, an event happening in time, and therefore fugitive. While pictures may or may not be mimetic, music rarely is, and that lack of external reference adds to the impression of fugitivity. When we look at a picture, we stand in a frontal, focalized orientation to an object at a certain distance from us. When we listen to music, even when we are seated in a hall, we are surrounded by an ambient phenomenon with no fixed location. Music sweeps over and through us. Arguably, because sound waves physically enter the body via the ear canal, music is present as much inside as outside of the listener. To judge from the number of books and articles on the two subjects, criticism finds it easier to discuss poetry’s relationship to visual art than its relationship to music, although, in the primacy it gives to sound and the way it unfolds in time, poetry has demonstrably more in common with music than with visual art. Stevens scholarship is not an exception, having been more focused over the years on the poet’s relationship to modern painting and visual art than on his relationship to music. Bart Eeckhout and Lisa Goldfarb’s The Poetic Music of Wallace Stevens adjusts that balance with the first monograph overview of the subject. Rather than a sustained argument, the book is structured as a series of semi-independent chapters exploring diverse topics, including music and memory, melody, birdsong and the sounds of nature, and Stevens’s relationship to modern European composers. Despite this variety of approach, a unified view of Stevens emerges. Stevens’s poetry, the co-authors write, is “an art of textual performance that invites open-ended interpretive processes and embodied experiences” in the service of a “musical aesthetic of transience, ephemerality, and affective intensification” (2). This view is not entirely new: it is consistent with the American pragmatist poet represented in philosophically oriented accounts of Stevens. But the focus on music, by putting Stevens into the company of modern European composers, makes for a rich recontextualization of his aesthetic thinking and fresh reference points for the reading of individual poems. Eeckhout and Goldfarb invite us to read “Of Mere Being,” for instance, with Richard Strauss’s Four Last Songs in mind. “Im Abendrot,” the last of the songs, concludes with a pair of flutes imitating birdcalls at dusk (an unusual moment of unmistakably mimetic music). The co-authors suggest that Stevens, a longtime admirer of Strauss, “might have been haunt[ed] . . . —in whatever manner: consciously, unconsciously, semiconsciously—” by those “warbling” flutes (117) when, in his last poem, he imagined a “gold-feathered” [End Page 114] bird singing “Without human feeling, a foreign song” (CPP 476). The link between Stevens’s poem and Strauss’s song is nicely worked out, but the conditional “might have been” raises questions about the status of the connection. When Eeckhout and Goldfarb go on to propose that Stevens might have been in the audience when Gustav Mahler conducted his First Symphony in New York, and that music might have informed his poem “The Worms at Heaven’s Gate,” some readers will balk at so much speculation. But the coauthors’ aim is less to insist on direct influence than to put Stevens’s poetry into conversation with modern orchestral music. There is no doubt Stevens tried to create poetic equivalents of certain musical effects. Referring to the presentation of the silver rose in Strauss’s Der Rosenkavalier, he wrote, “The glancing chords haunt me and sometimes I try to reproduce the effect of them in words” (L 744). Did he perhaps imagine orchestral composers as part of the audience for his poems? He did on at least one important occasion. “An Ordinary Evening in New Haven” was commissioned for the sesquicentennial...

Kimchi or gimchi? Perceived similarity between Korean lenis and Japanese voiced/voiceless stop sounds

When distinguishing stop consonants, Korean listeners use the fundamental frequency of the following vowel (F0) as well as the voice onset time (VOT). However, it is unclear whether the F0 and VOT of natural speech sounds play an effective role in hearing nonnative stops. In the present study, we examined whether Korean listeners perceive Japanese voiced stops, rather than Japanese voiceless stops, as being similar to Korean lenis stops depending on F0 and VOT. Native Korean listeners matched a speech sound starting with either a Japanese voiced or voiceless stop to a target. The targets were meaningful visual words starting with a lenis stop in Experiment 1 and meaningless speech sounds starting with a lenis stop in Experiment 2. Native Japanese listeners, who primarily use VOT for stop distinction, also participated in Experiment 2. The results revealed that the extent to which Korean listeners chose voiced stops was influenced consistently by F0, and the pattern of results differed between Korean and Japanese listeners. These findings suggest that even when hearing natural speech sounds, Korean listeners use F0 when judging the similarity between lenis and nonnative stops.

Comparing acoustic, semantic, and deep neural network models of natural sound representation in perceived dissimilarity and cerebral fMRI responses

Recognizing sounds implicates the cerebral transformation of input waveforms into semantic representations. Although past research identified the superior temporal gyrus (STG) as a crucial cortical region, the computational fingerprint of these cerebral transformations remains poorly characterized. Here, we contrasted the ability of pre-published acoustic, semantic, and sound-to-event deep neural network (DNN) models to account for the behavioral estimate of the perceived dissimilarity, and for the 7T fMRI responses to natural sounds in the absence of explicit task demands. We find that both perceived dissimilarity and STG fMRI responses are better predicted by sound-to-event DNNs, and, within the DNNs, by the layers intermediate between the input acoustic representation and the output semantic embedding. Our findings indicate that STG entails intermediate acoustic-to-semantic sound representations that neither acoustic nor semantic models can account for. These representations are compositional in nature and relevant to behavior.

Cross-sensory interference assessment after exposure to noise shows different effects in the blue crab olfactory and sound sensing capabilities

Underwater noise pollution is an increasing threat to marine ecosystems. Marine animals use sound in communication and orientation processes. The introduction of anthropogenic noise in their habitat can interfere with sound production and reception as well as with the acquisition of vital information through other sensory systems. In the blue crab (Callinectes sapidus), the statocyst is responsible for acoustic perception, and it is housed at the base of its first pair of antennae (antennule). The sensilla of the distal part of these antennule hosts the olfactory system, which is key for foraging. Given the anatomical proximity of the two sensory regions, we evaluated the possible interference of sound exposure with the crab ability to find food, by using an aquatic maze, and looked at the potential impairment of the righting reflex as well as at ultrastructural damages in statocysts. Although a significant effect was observed when looking at the time used by the animal to recover its habitual position (“righting reflex”), which was associated to lesions in the statocyst sensory epithelia, the time required to find food did not increase after the exposure to sound. When the crabs were exposed to natural sounds (marine background noise and sounds of their predators: Micropogonias undulates and Sciaenops ocellatus) they did not show significant differences in foraging behaviour. Although we found no unequivocal evidence of a negative impact of sound on olfactory capabilities, the study showed a clear righting reflex impairment correlated with ultrastructural damages of the statocysts. We argue that crab populations that cannot easily avoid noise sources due to their specific coastal distributions may incur in significant direct fitness costs (e.g. impairment of complex reflexes). This integrated approach to sound effect assessment could be used as a model for other invertebrate species to effectively monitor noise impact in marine environments.

A neuron model with unbalanced synaptic weights explains the asymmetric effects of anaesthesia on the auditory cortex.

Substantial progress in the field of neuroscience has been made from anaesthetized preparations. Ketamine is one of the most used drugs in electrophysiology studies, but how ketamine affects neuronal responses is poorly understood. Here, we used in vivo electrophysiology and computational modelling to study how the auditory cortex of bats responds to vocalisations under anaesthesia and in wakefulness. In wakefulness, acoustic context increases neuronal discrimination of natural sounds. Neuron models predicted that ketamine affects the contextual discrimination of sounds regardless of the type of context heard by the animals (echolocation or communication sounds). However, empirical evidence showed that the predicted effect of ketamine occurs only if the acoustic context consists of low-pitched sounds (e.g., communication calls in bats). Using the empirical data, we updated the naïve models to show that differential effects of ketamine on cortical responses can be mediated by unbalanced changes in the firing rate of feedforward inputs to cortex, and changes in the depression of thalamo-cortical synaptic receptors. Combined, our findings obtained in vivo and in silico reveal the effects and mechanisms by which ketamine affects cortical responses to vocalisations.

Blowing up Ti3C2TX MXene membrane for robust sound detection

Flexible pressure sensors have attracted great attention in health monitoring, human–machine interface, and soft robotics because of their simple device structure and easy to read signals. Two-dimensional (2D) materials (e.g., MXene) are promising candidates for constructing flexible pressure sensors due to their high conductivity and solution-based processability. Typically, during filtration, micrometer-sized MXene nanosheets are assembled into a thin membrane with plenty of wrinkles and folds in order to minimize the total energy. Herein, by taking advantage of this phenomenon, hydrazine hydrate is employed as a foaming agent to blow up the wrinkles and folds of MXene nanosheets in the membrane by gas species generated from the redox reactions, forming a porous foam. The as-prepared pressure sensor shows high sensitivity for a wide linear range (102.89 kPa−1 for 0–0.5 kPa and 2.86 kPa−1 for 2–10 kPa), low detection limit (1 Pa), fast response time (132 ms), and excellent durability (over 5000 cycles). As a detector, the MXene sensor can not only identify different sound signals and sound attributes by monitoring the vocal cord vibration but also distinguish various natural sounds transmitted through the air pressure waves caused by the sound transmission.

Two stages of bandwidth scaling drives efficient neural coding of natural sounds.

Theories of efficient coding propose that the auditory system is optimized for the statistical structure of natural sounds, yet the transformations underlying optimal acoustic representations are not well understood. Using a database of natural sounds including human speech and a physiologically-inspired auditory model, we explore the consequences of peripheral (cochlear) and mid-level (auditory midbrain) filter tuning transformations on the representation of natural sound spectra and modulation statistics. Whereas Fourier-based sound decompositions have constant time-frequency resolution at all frequencies, cochlear and auditory midbrain filters bandwidths increase proportional to the filter center frequency. This form of bandwidth scaling produces a systematic decrease in spectral resolution and increase in temporal resolution with increasing frequency. Here we demonstrate that cochlear bandwidth scaling produces a frequency-dependent gain that counteracts the tendency of natural sound power to decrease with frequency, resulting in a whitened output representation. Similarly, bandwidth scaling in mid-level auditory filters further enhances the representation of natural sounds by producing a whitened modulation power spectrum (MPS) with higher modulation entropy than both the cochlear outputs and the conventional Fourier MPS. These findings suggest that the tuning characteristics of the peripheral and mid-level auditory system together produce a whitened output representation in three dimensions (frequency, temporal and spectral modulation) that reduces redundancies and allows for a more efficient use of neural resources. This hierarchical multi-stage tuning strategy is thus likely optimized to extract available information and may underlies perceptual sensitivity to natural sounds.

Classification and ecological relevance of soundscapes in urban informal settlements

Abstract Sound exerts wide‐ranging influence on humans. The quality of that influence depends on the sound source and context in which it is perceived, but nature sounds are generally preferred by people and associated with health and well‐being benefits. In many environments, sounds are highly mixed giving rise to a multi‐source ‘soundscape’ that may vary through days or seasons. The complex and dynamic nature of soundscapes makes them challenging to quantify or classify to rigorously compare them and their contributing sources quantitatively through space and time. We address this challenge by developing an analytical procedure resulting in a generalized soundscape classification framework that (i) elucidates dominant sound sources (e.g. biophony vs. anthrophony) and (ii) can be used to improve our understanding of spatial and temporal variation in soundscapes across different contexts. We also address a knowledge gap in urban sound research by describing the soundscapes of urban informal settlements in Fiji and Indonesia. Despite the growing emphasis on improving the physical design and quality of life in urban informal settlements, little is known about soundscapes in these settings or their relationship to human health and well‐being. We identified seven soundscape classes representing relative dominance by (i) sustained geophony, biophony dominated by (ii) insect stridulation or (iii) bird song, anthrophony dominated by (iv) machines, (v) vehicles, (vi) human voices or (vii) a mixture of the former. These classes were applicable in both Indonesia and Fiji but differed in their prevalence between the countries, times of day and seasons in expected ways. Future automatic sorting of new sound data into this classification framework is provided by a supervised classification model that attained an overall testing accuracy of 94% and Cohen's kappa of 0.93. Our procedure yields broadly applicable, informative soundscape classes indicative of dominant sound sources, including natural sounds, that are known to have different effects on human health. Therefore, our soundscape classification framework can be used in conjunction with health, well‐being, or economic data, to aid the development, assessment and scaling of sustainable design solutions for liveable cities and especially for improving urban informal settlement environments. Read the free Plain Language Summary for this article on the Journal blog.

Collecting and mapping soundscape data across the 15 UK national parks

The soundscape approach, as understood by the ISO 12913 series, is most applied in urban settings, aiming beyond noise control in order to holistically employ its quantitative and qualitative facets. On the other side, the current understanding of the soundscape concept in bioacoustics and acoustic ecology is less focused on perception. There is generally a lot of public interest in how to preserve the opportunity for people to experience the "natural quiet" and "the sounds of nature", and the need to balance that with the protection of the natural areas and national parks from the noise that the visitors themselves generate while on site. However, specific investigations in these environments are scarce in the UK. Moreover, while there might be acoustic environments and sound sources that people identify with national parks, they are not systematically documented nor implemented in the national parks' management plans. Therefore, we propose a framework starting with a quasi-crowd-sourced acquisition of soundscape data and mapping those to a freely accessible GIS platform such as Google Earth, leading towards identifying soundscape conservation targets and management tools for the UK national parks, further raising the awareness of the value of sound as a resource.

Sound masking of residential noise by a birdsong depending on spectral and temporal characteristics

This study aimed to investigate the sound masking according to spectral and temporal characteristics of residential noise and natural sound through auditory experiment. Since there are various types of residential noise sources (maskee) and natural sounds (masker), stimuli to be used for experiment were selected by dividing the sound source groups through the k-means cluster method. The stimuli consisted of a total of 7 maskee including a brown noise, and 7 masker (birdsongs and water sounds). In the auditory experiment, the preference of masker and the annoyance and unpleasantness of single maskee and masker and mixed sources (maskee+masker) were investigated. Result showed that Phoenicurus auroreus and stream-Fast were the highest preference among masker, and masker preference were significantly correlated with masker annoyance. In addition, it was found that impact sound (children jumping and running and piledriver) show relatively higher annoyance than other sound sources. Relative annoyance of mixed sources (maskee+masker) to single maskee was analyzed and masking effect was discussed based on spectral and temporal and the Zwicker's parameters of each sound source.

Why listening matters

Sound is the only one of our senses that remains active while we sleep. Through hearing we test our safety at distance and in the dark. It can also condition the way we feel. Noise can affect our health and well-being negatively but sound may do so positively. Acousticians are used to measuring noise but the more positive effects of sound less well understood. The idea that sound can reduce stress and inhance our sense of wellbeing and even improve our health is a tantalising target for soundscape designs in the future but we need more fully to understand how to achieve it in a scientific way. We know that a tranquil place does not need to be quiet for instance, and that context and non-acoustic factors are important in the perception of tranquillity. We know that natural sounds: waves breaking, rain, leaves rustling, water babbling, birdsong; and some anthropogenic sounds: a familiar voice, the murmur of conversation, music; can contribute to a positive soundscape. Some examples and the current understanding of why this is, taking in cues from neuroscience, medicine and psychoacoustics are explored leading to quantification of these benefits for application in soundscape analysis and, ultimately, design.