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1

Loudness Functions and Binaural Loudness Summation in Bilateral Cochlear Implant Users

Kordus M., Zera J.

Archives of Acoustics

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2017

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Vol. 42, No. 3

351--364

EN

Loudness functions and binaural loudness summation was investigated in acoustically stimulated bilaterally implanted cochlear implant users. The study was aimed at evaluating growth of loudness functions and binaural loudness summation in cochlear implant subjects as a function of stimulus presentation level at different frequencies. Loudness was assessed using a rating procedure on a scale of 0 to 100. Three experimental conditions were tested: monaural right, monaural left and binaural, each with bands of noise with center frequencies of 0.25, 1, and 4 kHz. Fifteen implanted and five normal-hearing subjects (control group) participated in the experiments. Results demonstrated large variability in the slopes of the loudness functions and the presence of loudness summation in bilateral cochlear implant users, with large individual differences among subjects.

2

Characterizing Subjective Noisiness in Hospital Lobbies

Chen C.-Y.

Archives of Acoustics

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2015

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Vol. 40, No. 2

235--246

EN

The present study was conducted in the lobbies of 16 Taiwanese urban hospitals to establish what contributes to the degree of noisiness experienced by patients and those accompanying them. Noise level measurements were then conducted by 15 min equivalent sound pressure levels (LAeq, 15m, dB) during daytime hours. The average LAeq itself was found to be poorly related to perceived noisiness. Levels variations were better correlated, more continual noise may actually be perceived as noisier. According to the findings of a multiple linear stepwise regression model (r = 0.91, R2 = 0.83), the 3 independent variables shown to have the largest effects on perceived noisiness were 1) 1/(L5−L95), 2) effective duration of the normalized autocorrelation function (_e, h), of all LAeq, 15m over 9–17, and 3) percentile loudness, N5, 15m. These results resemble previous studies that had assumed that a larger fluctuation of noise level corresponds to less annoyance experienced for mixed traffic noise studied in a laboratory situation. As an advanced approach, for hospital noise that consisted of 12 audible noise events, subjective noisiness were evaluated by the noise time structure analyzed by autocorrelation with loudness and levels variation.

3

Perceptually Correlated Parameters of Musical Instrument Tones

Beauchamp J. W.

Archives of Acoustics

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2011

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Vol. 36, No. 2

225-238

EN

In Western music culture instruments have been developed according to unique instrument acoustical features based on types of excitation, resonance, and radiation. These include the woodwind, brass, bowed and plucked string, and percussion families of instruments. On the other hand, instrument performance depends on musical training, and music listening depends on perception of instrument output. Since musical signals are easier to understand in the frequency domain than the time domain, much effort has been made to perform spectral analysis and extract salient parameters, such as spectral centroids, in order to create simplified synthesis models for musical instrument sound synthesis. Moreover, perceptual tests have been made to determine the relative importance of various parameters, such as spectral centroid variation, spectral incoherence, and spectral irregularity. It turns out that the importance of particular parameters depends on both their strengths within musical sounds as well as the robustness of their effect on perception. Methods that the author and his colleagues have used to explore timbre perception are: 1) discrimination of parameter reduction or elimination; 2) dissimilarity judgments together with multidimensional scaling; 3) informal listening to sound morphing examples. This paper discusses ramifications of this work for sound synthesis and timbre transposition.

4

Telekomunikacja a badanie subiektywnych cech dźwięku

Żera J.

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2005

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nr 10

381-385

PL

Przedstawiono elementy metodologii badań wrażeniowych cech dźwięku w szkicowym ujęciu historycznym. Omówiono wybrane osiągnięcia w zakresie badań subiektywnych cech dźwięku, jako przykłady badań prowadzonych na potrzeby rozwoju telekomunikacji. Przedstawiono sylwetki niektórych osób związanych zawodowo z telekomunikacją zajmujących się badaniami subiektywnych cech dźwięku.

EN

Certain facts related to methods used for subjective assessment of sound with some historical background are described. Examples of research on perception of sound conducted in response to or initiated by the needs of telephony and telecommunication is presented. Contribution of certain individuals strongly influencing the research in the field of sound perception and mechanisms of hearing is portrayed.

5

Preferred Levels of Auditory Danger Signals

Żera J., Nagórski A.

International Journal of Occupational Safety and Ergonomics

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2000

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Zeszyt Specjalny

111--117

EN

An important issue at the design stage of the auditory danger signal for a safety system is the signal audibility under various conditions of background noise. The auditory danger signal should be clearly audible but it should not be too loud to avoid fright, startling effects, and nuisance complaints. Criteria for designing auditory danger signals are the subject of the ISO 7731 (International Organization for Standardization [ISO], 1986) international standard and the EN 457 European standard (European Committee for Standardization [CEN], 1992). It is required that the A-weighted sound pressure level of the auditory danger signal is higher in level than the background noise by 15 dB. In this paper, the results of an experiment are reported, in which listeners adjusted most preferred levels of 3 danger signals (tone, sweep, complex sound) in the presence of a noise background (pink noise and industrial noise). The measurements were done for 60-, 70-, 80- and 90-dB A-weighted levels of noise. Results show that for 60-dB level of noise the most preferred level of the danger signal is 10 to 20 dB above the noise level. However, for 90-dB level of noise, listeners selected a level of the danger signal that was equal to the noise level. Results imply that the criterion in the existing standards is conservative as it requires the level of the danger signal to be higher than the level of noise regardless of the noise level.