Aircraft noise-Auralization-based assessment of weather-dependent effects on loudness and sharpness.

This paper deals with the question of how specific weather conditions affect the perception of aircraft noise. Auralization is a suitable method by enabling parametrical decompositions of the overall aircraft noise scenario into source and propagation components. Considering influences on the auditory perception, the signal processing chain contains different virtual receivers and post processing using psychoacoustic hearing models. For broad coverage, generic standardized as well as measurement-based atmosphere models with variation of ground impedances such as soil data are evaluated. These variations are given aircraft noise measurement values based on A-weighted sound pressure levels LA and psychoacoustic measures regarding loudness, N, and sharpness, S. The results show an immense influence of weather conditions on A-weighted sound pressure levels and on psychoacoustic perception of aircraft noise, too. The weather-dependent differences of A-weighted sound pressure levels are up to 15 dBA and relative differences regarding loudness of factor 1.6 and sharpness of factor 2.0 occur. The approach can be used to get a better understanding of how the temporal statistics of specific local weather conditions and their perceptual consequences may lead to improved taxation of actual noise events and to an improved basis for long-term averages of aircraft noise effects.

Bayesian Applications in Auditory Research.

Purpose This article presents a basic exploration of Bayesian inference to inform researchers unfamiliar to this type of analysis of the many advantages this readily available approach provides. Method First, we demonstrate the development of Bayes' theorem, the cornerstone of Bayesian statistics, into an iterative process of updating priors. Working with a few assumptions, including normalcy and conjugacy of prior distribution, we express how one would calculate the posterior distribution using the prior distribution and the likelihood of the parameter. Next, we move to an example in auditory research by considering the effect of sound therapy for reducing the perceived loudness of tinnitus. In this case, as well as most real-world settings, we turn to Markov chain simulations because the assumptions allowing for easy calculations no longer hold. Using Markov chain Monte Carlo methods, we can illustrate several analysis solutions given by a straightforward Bayesian approach. Conclusion Bayesian methods are widely applicable and can help scientists overcome analysis problems, including how to include existing information, run interim analysis, achieve consensus through measurement, and, most importantly, interpret results correctly. Supplemental Material https://doi.org/10.23641/asha.7822592.

A Laboratory Evaluation of Contextual Factors Affecting Ratings of Speech in Noise: Implications for Ecological Momentary Assessment.

OBJECTIVES: As hearing aid outcome measures move from retrospective to momentary assessments, it is important to understand how contextual factors influence subjective ratings. Under laboratory-controlled conditions, we examined whether subjective ratings changed as a function of acoustics, response timing, and task variables. DESIGN: Eighteen adults (age 21 to 85 years; M = 51.4) with sensorineural hearing loss were fitted with hearing aids. Sentences in noise were presented at 3 overall levels (50, 65, and 80 dB SPL) and 3 signal to noise ratios (0, +5, and +10 dB signal to noise ratio [SNR]). Listeners rated three sound quality dimensions (intelligibility, noisiness, and loudness) under four experimental conditions that manipulated timing and task focus. RESULTS: The quality ratings changed as the acoustics changed: intelligibility ratings increased with input level (p < 0.05); noisiness ratings increased at poorer SNRs (p < 0.05); and loudness ratings increased as input level increased (p < 0.05). Timing of rating was significant at the highest presentation level (80 dB SPL): Participants gave higher noise ratings while listening to the signal than afterward (p < 0.05). Presence of a secondary task had no significant effect on ratings (p > 0.1). CONCLUSIONS: The findings of this laboratory study provide evidence to support the conclusion that group-mean listener ratings of loudness, noisiness, and intelligibility change in predictable ways as level and SNR of the speech in noise stimulus are altered. They also provide weak evidence to support the conclusion that timing of the ratings (during or immediately after sound exposure) can affect noisiness ratings under certain conditions, but no evidence to support the conclusion that timing affects other quality ratings. There is also no evidence to support the conclusion that quality ratings are influenced by the presence of, or focus on, a secondary nonauditory task of the type used here.

Objective assessment of electrode discrimination with the auditory change complex in adult cochlear implant users.

The spatial auditory change complex (ACC) is a cortical response elicited by a change in place of stimulation. There is growing evidence that it provides a useful objective measure of electrode discrimination in cochlear implant (CI) users. To date, the spatial ACC has only been measured in relatively experienced CI users with one type of device. Early assessment of electrode discrimination could allow auditory stimulation to be optimized during a potentially sensitive period of auditory rehabilitation. In this study we used a direct stimulation paradigm to measure the spatial ACC in both pre- and post-lingually deafened adults. We show that it is feasible to measure the spatial ACC in different CI devices and as early as 1 week after CI switch-on. The spatial ACC has a strong relationship with performance on a behavioural discrimination task and in some cases provides information over and above behavioural testing. We suggest that it may be useful to measure the spatial ACC to guide auditory rehabilitation and improve hearing performance in CI users.

Clinical trials supported by the Tinnitus Research Consortium: Lessons learned, the Southern Illinois University experience.

The Tinnitus Research Consortium funded three clinical trials investigating treatments for chronic bothersome tinnitus at Southern Illinois University School of Medicine. The trials were designed to measure the subjective changes in tinnitus distress using standardized questionnaires and objective changes in tinnitus loudness using psychophysical matching procedures. The results of the first two trials have been published and are summarized here. The first trial investigated the effect of gabapentin on the loudness and annoyance of tinnitus in adults with chronic bothersome tinnitus with and without a history of acoustic trauma. A small but significant number of subjects reported decreased tinnitus annoyance that corresponded with a decrease in objective measures of tinnitus loudness during active drug treatment with a washout effect during placebo treatment. The second trial compared the effect of tinnitus retraining therapy (TRT) on adults with normal to near-normal hearing and chronic bothersome tinnitus to treatment with general counseling without acoustic enrichment. Significant improvements in tinnitus severity, but not in objective psychometric measures of tinnitus loudness, occurred in both treatment groups, however a greater effect was observed in the TRT group compared with the control group. The third trial is nearing completion and investigates the long-term results of tinnitus retraining therapy on chronic bothersome tinnitus in adults with hearing loss. Significant lessons and observations on conducting tinnitus clinical trials were learned from these three trials. The challenges of recruiting and retaining study participants is discussed. More importantly, the reliability and stability of the Tinnitus Handicap Inventory (THI) over long intervals is presented. The implications of this variability for the design and interpretation of future tinnitus studies is discussed. This article is part of a Special Issue entitled .

Validating a short Bulgarian version of a psychometric instrument for multidimensional noise sensitivity assessment.

BACKGROUND: Noise sensitivity (NS) is a key construct in the fields of hygiene, planning and occupational medicine. It refers to a personality trait representing the reactivity to noise and is associated with various psycho-physiological health outcomes. AIM: This study aimed to develop a shorter version of the original Noise Sensitivity Questionnaire (NoiSeQ), retaining its dimensions and assess its validity and reliability. METHODS: A test-retest study was carried out in a convenience sample of 56 participants. A short 15-item form of the original NoiSeQ (NoiSeQSF) questionnaire was developed and then administered. All major analyses were based on the coefficient of equivalence and stability, the generalizability theory and linear regression. RESULTS: Relative (rho = 0.83) and absolute ((phi = 0.80) G coefficients for global NS exceeded the lower reliability limit according to G- and D-studies. Sleep subscale can readily be used to assess sleep-related NS (rho = 0.76/phi = 0.75). Moreover, NoiSeQSF predicted some cardiac symptoms (with age of participants as a moderator factor), which demonstrated nomological validity. CONCLUSION: NoiSeQSF is a reliable estimate for global NS and NS related to sleep quality. It might prove useful to experts in environmental hygiene, urban planning and occupational diseases when dealing with noise-impaired occupational, social or psycho-physiological functioning.

Objective assessment of spectral ripple discrimination in cochlear implant listeners using cortical evoked responses to an oddball paradigm.

Cochlear implants (CIs) can partially restore functional hearing in deaf individuals. However, multiple factors affect CI listener's speech perception, resulting in large performance differences. Non-speech based tests, such as spectral ripple discrimination, measure acoustic processing capabilities that are highly correlated with speech perception. Currently spectral ripple discrimination is measured using standard psychoacoustic methods, which require attentive listening and active response that can be difficult or even impossible in special patient populations. Here, a completely objective cortical evoked potential based method is developed and validated to assess spectral ripple discrimination in CI listeners. In 19 CI listeners, using an oddball paradigm, cortical evoked potential responses to standard and inverted spectrally rippled stimuli were measured. In the same subjects, psychoacoustic spectral ripple discrimination thresholds were also measured. A neural discrimination threshold was determined by systematically increasing the number of ripples per octave and determining the point at which there was no longer a significant difference between the evoked potential response to the standard and inverted stimuli. A correlation was found between the neural and the psychoacoustic discrimination thresholds (R2=0.60, p<0.01). This method can objectively assess CI spectral resolution performance, providing a potential tool for the evaluation and follow-up of CI listeners who have difficulty performing psychoacoustic tests, such as pediatric or new users.

Assessment of rural soundscapes with high-speed train noise.

In the present study, rural soundscapes with high-speed train noise were assessed through laboratory experiments. A total of ten sites with varying landscape metrics were chosen for audio-visual recording. The acoustical characteristics of the high-speed train noise were analyzed using various noise level indices. Landscape metrics such as the percentage of natural features (NF) and Shannon's diversity index (SHDI) were adopted to evaluate the landscape features of the ten sites. Laboratory experiments were then performed with 20 well-trained listeners to investigate the perception of high-speed train noise in rural areas. The experiments consisted of three parts: 1) visual-only condition, 2) audio-only condition, and 3) combined audio-visual condition. The results showed that subjects' preference for visual images was significantly related to NF, the number of land types, and the A-weighted equivalent sound pressure level (LAeq). In addition, the visual images significantly influenced the noise annoyance, and LAeq and NF were the dominant factors affecting the annoyance from high-speed train noise in the combined audio-visual condition. In addition, Zwicker's loudness (N) was highly correlated with the annoyance from high-speed train noise in both the audio-only and audio-visual conditions.

The production effect: costs and benefits in free recall.

The production effect, the memorial benefit for information read aloud versus silently, has been touted as a simple memory improvement tool. The current experiments were designed to evaluate the relative costs and benefits of production using a free recall paradigm. Results extend beyond prior work showing a production effect only when production is manipulated within subject, not between, using a free recall paradigm. Furthermore, the results also indicate that the production effect is primarily driven by decreased memory for items read silently, not increased memory for items read aloud.

Psychoacoustic assessment to improve tinnitus diagnosis.

The diagnosis of tinnitus relies on self-report. Psychoacoustic measurements of tinnitus pitch and loudness are essential for assessing claims and discriminating true from false ones. For this reason, the quantification of tinnitus remains a challenging research goal. We aimed to: (1) assess the precision of a new tinnitus likeness rating procedure with a continuous-pitch presentation method, controlling for music training, and (2) test whether tinnitus psychoacoustic measurements have the sensitivity and specificity required to detect people faking tinnitus. Musicians and non-musicians with tinnitus, as well as simulated malingerers without tinnitus, were tested. Most were retested several weeks later. Tinnitus pitch matching was first assessed using the likeness rating method: pure tones from 0.25 to 16 kHz were presented randomly to participants, who had to rate the likeness of each tone to their tinnitus, and to adjust its level from 0 to 100 dB SPL. Tinnitus pitch matching was then assessed with a continuous-pitch method: participants had to match the pitch of their tinnitus to an external tone by moving their finger across a touch-sensitive strip, which generated a continuous pure tone from 0.5 to 20 kHz in 1-Hz steps. The predominant tinnitus pitch was consistent across both methods for both musicians and non-musicians, although musicians displayed better external tone pitch matching abilities. Simulated malingerers rated loudness much higher than did the other groups with a high degree of specificity (94.4%) and were unreliable in loudness (not pitch) matching from one session to the other. Retest data showed similar pitch matching responses for both methods for all participants. In conclusion, tinnitus pitch and loudness reliably correspond to the tinnitus percept, and psychoacoustic loudness matches are sensitive and specific to the presence of tinnitus.

Computer-automated tinnitus assessment: noise-band matching, maskability, and residual inhibition.

BACKGROUND: Psychoacoustic measures of tinnitus typically include loudness and pitch match, minimum masking level (MML), and residual inhibition (RI). We previously developed and documented a computer-automated tinnitus evaluation system (TES) capable of subject-guided loudness and pitch matching. The TES was further developed to conduct computer-aided, subject-guided testing for noise-band matching (NBM), MML, and RI. PURPOSE: The purpose of the present study was to document the capability of the upgraded TES to obtain measures of NBM, MML, and RI, and to determine the test-retest reliability of the responses obtained. RESEARCH DESIGN: Three subject-guided, computer-automated testing protocols were developed to conduct NBM. For MML and RI testing, a 2-12 kHz band of noise was used. All testing was repeated during a second session. STUDY SAMPLE: Subjects meeting study criteria were selected from those who had previously been tested for loudness and pitch matching in our laboratory. A total of 21 subjects completed testing, including seven females and 14 males. RESULTS: The upgraded TES was found to be fairly time efficient. Subjects were generally reliable, both within and between sessions, with respect to the type of stimulus they chose as the best match to their tinnitus. Matching to bandwidth was more variable between measurements, with greater consistency seen for subjects reporting tonal tinnitus or wide-band noisy tinnitus than intermediate types. Between-session repeated MMLs were within 10 dB of each other for all but three of the subjects. Subjects who experienced RI during Session 1 tended to be those who experienced it during Session 2. CONCLUSIONS: This study may represent the first time that NBM, MML, and RI audiometric testing results have been obtained entirely through a self-contained, computer-automated system designed specifically for use in the clinic. Future plans include refinements to achieve greater testing efficiency.

Acoustical and perceptual assessment of water sounds and their use over road traffic noise.

This paper examines physical and perceptual properties of water sounds generated by small to medium sized water features that have applications for road traffic noise masking. A large variety of water sounds were produced in the laboratory by varying design parameters. Analysis showed that estimations can be made on how these parameters affect sound pressure levels, frequency content, and psychoacoustic properties. Comparisons with road traffic noise showed that there is a mismatch between the frequency responses of traffic noise and water sounds, with the exception of waterfalls with high flow rates, which can generate large low frequency levels comparable to traffic noise. Perceptual assessments were carried out in the context of peacefulness and relaxation, where both water sounds and noise from dense road traffic were audible. Results showed that water sounds should be similar or not less than 3 dB below the road traffic noise level (confirming previous research), and that stream sounds tend to be preferred to fountain sounds, which are in turn preferred to waterfall sounds. Analysis made on groups of sounds also indicated that low sharpness and large temporal variations were preferred on average, although no acoustical or psychoacoustical parameter correlated well with the individual sound preferences.

The role of catastrophizing in recent onset tinnitus: its nature and association with tinnitus distress and medical utilization.

OBJECTIVE: Persistent tinnitus affects 10 to 15% of adults. Little is understood about why only a small percentage of patients become severely affected. Catastrophic thinking has been suggested as one potentially relevant factor that might influence a patient's coping behavior, and thus tinnitus habituation. The current study investigates the concept of tinnitus catastrophizing and its relation with distress and medical utilization in recent onset tinnitus. DESIGN: Participants were administered a survey assessing catastrophizing, tinnitus distress, medical utilization, coping, and mood disturbance. Regression analyses investigated the nature of tinnitus catastrophizing and its contributions to distress and health care utilization. STUDY SAMPLE: 278 subjects with tinnitus for less than six months were recruited from Ear-Nose-Throat units, through the internet, and newspaper articles. RESULTS: Controlling for background variables, high subjective tinnitus loudness, low behavioral coping, and depressive symptoms were significantly associated with tinnitus catastrophizing. Furthermore, greater tinnitus catastrophizing was related to higher distress and more frequent medical visits. CONCLUSIONS: Tinnitus catastrophizing appears to be pivotal already at an early stage of tinnitus experience. Addressing catastrophizing by specific prevention and intervention programs might reduce the development of distress and medical utilization in the long term. Longitudinal studies are required to clarify cause-effect relations.

Output capabilities of personal music players and assessment of preferred listening levels of test subjects: outlining recommendations for preventing music-induced hearing loss.

OBJECTIVES/HYPOTHESIS: Our goal was to assess the impact of personal music players, earphones, and music styles on output, the subject's preferred listening levels, and outline recommendations for the prevention of music-induced hearing loss. STUDY DESIGN: Experimental study. Personal music players' output capabilities and volunteers' preferred output levels were assessed in different settings. Based on current noise-induced hearing loss exposure limits, recommendations were outlined. METHODS: On three different devices and earphone types and 10 music styles, free field equivalent sound pressure output levels were assessed by applying a microphone probe inside the auditory canal. Forty-five hearing-healthy volunteers were asked to select preferred listening levels in different background noise scenarios. RESULTS: Sound pressure output reached 126 dB. No difference was found between device types, whereas earbud and supra-aural earphones showed significantly lower outputs than in-ear earphones (P < .001). Three distinct music style groups were identified with as much as 14.4 dB difference between them. In silence, 17.8% of volunteers spontaneously selected a listening level above 85 dB. With 90 dB background noise, 40% selected a level above 94 dB. Earphone attenuation capability was found to correlate significantly with preferred level reductions (r = 0.585, P < .001). In-ear and especially supra-aural earphones reduced preferred listening levels the most. CONCLUSIONS: Safe-use recommendations were outlined, whereas selecting the lowest volume setting comfortable remained the main suggestion. High background noise attenuating earphones may help in reducing comfortable listening levels and should be preferred. A risk table was elaborated, presenting time limits before reaching a risky exposure.

Estimating occupant satisfaction of HVAC system noise using quality assessment index.

Noise may be defined as any unwanted sound. Sound becomes noise when it is too loud, unexpected, uncontrolled, happens at the wrong time, contains unwanted pure tones or unpleasant. In addition to being annoying, loud noise can cause hearing loss, and, depending on other factors, can affect stress level, sleep patterns and heart rate. The primary object for determining subjective estimations of loudness is to present sounds to a sample of listeners under controlled conditions. In heating, ventilation and air conditioning (HVAC) systems only the ventilation fan industry (e.g., bathroom exhaust and sidewall propeller fans) uses loudness ratings. In order to find satisfaction, percent of exposure to noise is the valuable issue for the personnel who are working in these areas. The room criterion (RC) method has been defined by ANSI standard S12.2, which is based on measured levels of in HVAC systems noise in spaces and is used primarily as a diagnostic tool. The RC method consists of a family of criteria curves and a rating procedure. RC measures background noise in the building over the frequency range of 16-4000 Hz. This rating system requires determination of the mid-frequency average level and determining the perceived balance between high-frequency (HF) sound and low-frequency (LF) sound. The arithmetic average of the sound levels in the 500, 1000 and 2000 Hz octave bands is 44.6 dB; therefore, the RC 45 curve is selected as the reference for spectrum quality evaluation. The spectral deviation factors in the LF, medium-frequency sound and HF regions are 2.9, 7.5 and -2.3, respectively, giving a Quality Assessment Index (QAI) of 9.8. This concludes the QAI is useful in estimating an occupant's probable reaction when the system design does not produce optimum sound quality. Thus, a QAI between 5 and 10 dB represents a marginal situation in which acceptance by an occupant is questionable. However, when sound pressure levels in the 16 or 31.5 Hz octave bands exceed 65 dB, vibration in lightweight office construction is possible.

The objective-subjective assessment of noise: young adults can estimate loudness of events and lifestyle noise.

OBJECTIVE: The aim of the study was to establish whether individuals can subjectively estimate: (1) the loudness of events with respect to the objectively measured noise level; and (2) the overall loudness of their daily noise exposure level. DESIGN: Participants wore personal noise exposure meters for up to five days. During this time, participants kept diaries of daily events and estimated the loudness of these events and their overall noise exposure using 1-to-10 rating scales. STUDY SAMPLE: A group of 45 volunteers aged between 18 and 35 years participated in the study. RESULTS: 86% of participants' subjective estimates were significantly correlated with the objective noise measurements. Multiple regression showed that age, overall lifestyle noise, and diary quality were predictors of the strength of correlation observed. In addition participants' subjective estimates of their overall noise exposure were significantly correlated with their actual average daily noise exposure. CONCLUSIONS: Results suggest that individuals can make a reasonable estimate of the loudness of events they experience and the overall level of noise they experience. These results may have significant influence for those interested in producing effective hearing health awareness programs in that individuals may be capable of assessing their own degree of hazard exposure.

Concert hall acoustics assessment with individually elicited attributes.

Concert hall acoustics was evaluated with a descriptive sensory analysis method by employing an individual vocabulary development technique. The goal was to obtain sensory profiles of three concert halls by eliciting perceptual attributes for evaluation and comparison of the halls. The stimuli were gathered by playing back anechoic symphony music from 34 loudspeakers on stage in each concert hall and recording the sound field with a microphone array. Four musical programs were processed for multichannel 3D sound reproduction in the actual listening test. Twenty screened assessors developed their individual set of attributes and performed a comparative evaluation of nine seats, three in each hall. The results contain the distinctive groups of elicited attributes and show good agreement within assessors, even though they applied individual attributes when rating the samples. It was also found that loudness and distance gave the strongest perceptual direction to the principal component basis. In addition, the study revealed that the perception of reverberance is related to the size of the space or to the enveloping reverberance, depending on the assessor.

Assessment of auditory nonlinearity for listeners with different hearing losses using temporal masking and categorical loudness scaling.

A dysfunction or loss of outer hair cells (OHC) and inner hair cells (IHC), assumed to be present in sensorineural hearing-impaired listeners, affects the processing of sound both at and above the listeners' hearing threshold. A loss of OHC may be responsible for a reduction of cochlear gain, apparent in the input/output function of the basilar membrane and steeper-than-normal growth of loudness with level (recruitment). IHC loss is typically assumed to cause a level-independent loss of sensitivity. In the current study, parameters reflecting individual auditory processing were estimated using two psychoacoustic measurement techniques. Hearing loss presumably attributable to IHC damage and low-level (cochlear) gain were estimated using temporal masking curves (TMC). Hearing loss attributable to OHC (HL(OHC)) was estimated using adaptive categorical loudness scaling (ACALOS) and by fitting a loudness model to measured loudness functions. In a group of listeners with thresholds ranging from normal to mild-to-moderately impaired, the loss in low-level gain derived from TMC was found to be equivalent with HL(OHC) estimates inferred from ACALOS. Furthermore, HL(OHC) estimates obtained using both measurement techniques were highly consistent. Overall, the two methods provide consistent measures of auditory nonlinearity in individual listeners, with ACALOS offering better time efficiency.

Preference for one or two hearing AIDS among adult patients.

OBJECTIVES: Most practitioners believe that use of two hearing aids is the ideal fitting for adults with bilateral symmetrical hearing loss. However, previous research has consistently shown that a substantial proportion of these patients actually prefer to use only one hearing aid. This study explored whether this pattern of preferences is seen with technologically advanced hearing aids. In addition, a selection of variables that were available prefitting were used to attempt to predict which patients will prefer one hearing aid rather than two. DESIGN: The study was designed as a 12-week field trial including structured and unstructured use of one and two hearing aids. Ninety-four subjects with mild to moderate bilaterally symmetrical hearing loss were bilaterally fit with 2005-2007 era hearing aids. Potential predictors included demographic, audiometric, auditory lifestyle, personality, and binaural processing variables. After the field trial, each subject stated his or her preference for one or two hearing aids and completed three self-report outcome questionnaires for their preferred fitting. RESULTS: Previous research was confirmed with modern technology hearing aids: after the field trial, 46% of the subjects preferred to use one hearing aid rather than two. Subjects who preferred two hearing aids tended to report better real-world outcomes than those who preferred one. Subjects who reported more hearing problems in daily life, who experienced more binaural loudness summation, and whose ears were more equivalent in dichotic listening were more likely to prefer to use two hearing aids. Contrary to conventional wisdom (ideas that are generally accepted as true), audiometric hearing loss and auditory lifestyle were not predictive of aiding preference. However, the best predictive approach from these data yielded accurate predictions for only two-thirds of the subjects. CONCLUSIONS: Evidence-based practice calls for a conscientious melding of current evidence, clinical judgment, and patient preferences. The results of this research challenge practitioners to recognize that many patients who seem to be ideal candidates for bilateral aiding will actually prefer to wear only one hearing aid. Furthermore, at this time, there is no accurate method that will predict which patients will prefer one hearing aid rather than two. At present, the most effective approach open to practitioners would be to conduct a candid unbiased systematic field trial allowing each patient to compare unilateral and bilateral fittings in daily life. This might necessitate more fitting sessions and could perhaps add to the practitioner's burden. This downside should be weighed against the additional patient satisfaction that can be anticipated as a result of transparency in the fitting protocol, collaboration with the patient in the treatment decisions, and the knowledge of selecting the most cost-effective patient-centered solution.

Perceptual assessment of quality of urban soundscapes with combined noise sources and water sounds.

In this study, urban soundscapes containing combined noise sources were evaluated through field surveys and laboratory experiments. The effect of water sounds on masking urban noises was then examined in order to enhance the soundscape perception. Field surveys in 16 urban spaces were conducted through soundwalking to evaluate the annoyance of combined noise sources. Synthesis curves were derived for the relationships between noise levels and the percentage of highly annoyed (%HA) and the percentage of annoyed (%A) for the combined noise sources. Qualitative analysis was also made using semantic scales for evaluating the quality of the soundscape, and it was shown that the perception of acoustic comfort and loudness was strongly related to the annoyance. A laboratory auditory experiment was then conducted in order to quantify the total annoyance caused by road traffic noise and four types of construction noise. It was shown that the annoyance ratings were related to the types of construction noise in combination with road traffic noise and the level of the road traffic noise. Finally, water sounds were determined to be the best sounds to use for enhancing the urban soundscape. The level of the water sounds should be similar to or not less than 3 dB below the level of the urban noises.