scholarly journals Impulse Noise: Can Hitting a Softball Harm Your Hearing?

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Korrine Cook ◽  
Samuel R. Atcherson
Keyword(s):  
Spectral Analysis ◽  
Frequency Response ◽  
Sound Pressure Level ◽  
Impulse Noise ◽  
Sound Pressure ◽  
Pressure Level ◽  
Noise Floor ◽  
Playing Field ◽  
Multiple Exposures ◽  
Amplitude Frequency Response

The purpose of this study is to identify whether or not different materials of softball bats (wooden, aluminum, and composite) are a potential risk harm to hearing when batting players strike a 12′′ core .40 softball during slow, underhand pitch typical of recreational games. Peak sound pressure level measurements and spectral analyses were conducted for three controlled softball pitches to a batting participant using each of the different bat materials in an unused outdoor playing field with regulation distances between the pitcher’s mound and batter’s box. The results revealed that highest recorded peak sound pressure level was recorded from the aluminum (124.6 dBC) bat followed by the composite (121.2 dBC) and wooden (120.0 dBC) bats. Spectral analysis revealed composite and wooden bats with similar broadly distributed amplitude-frequency response. The aluminum bat also produced a broadly distributed amplitude-frequency response, but there were also two very distinct peaks at around 1700 Hz and 2260 Hz above the noise floor that produced its ringing (or ping) sound after being struck. Impulse (transient) sounds less than 140 dBC may permit multiple exposures, and softball bats used in a recreational slow pitch may pose little to no risk to hearing.

scholarly journals Analysis and Development of Hybrid Earphone Combining Balanced-Armature and Dynamic Receivers

2019 ◽  
Vol 9 (23) ◽  
pp. 5047
Author(s):  
Yuan-Wu Jiang ◽  
Dan-Ping Xu ◽  
Zhi-Xiong Jiang ◽  
Jun-Hyung Kim ◽  
Sang-Moon Hwang
Keyword(s):  
Frequency Response ◽  
Root Mean Square ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Sound Quality ◽  
Pressure Level ◽  
Analysis Tool ◽  
Mean Square ◽  
Rapid Progress ◽  
Audio Output

With the rapid progress in the development of multimedia devices, earphones have become increasingly important as audio output tools. Hybrid earphones combining balanced-armature (BA) and dynamic receivers can produce better performance over a wider range when compared to the earphones with BA receiver alone (BA earphones) or dynamic receiver alone (dynamic earphones). BA and dynamic earphones are multi-physics products that exhibit coupling between the electromagnetic, mechanical, and acoustic domains. In this study, an analysis tool is developed to design a hybrid earphone based on the conventional BA and dynamic earphones. Using the developed analysis tool, an acoustic tube is optimized to match the earphone target curve and obtain improved sound quality. A prototype is manufactured and tested, and the experimental results verify the feasibility and effectiveness of the developed analysis tool. The root-mean-square value of the sound pressure level (SPL) deviation of the hybrid earphone with the optimized acoustic tube is 4.60, whereas those for the dynamic and BA earphones are 8.94 and 6.04, respectively. Thus, it is verified that the frequency response is improved using the hybrid earphone developed herein.

A Calibration Procedure for the Assessment of Thresholds above 8000 Hz

1982 ◽  
Vol 25 (4) ◽  
pp. 618-623 ◽  
Author(s):  
Patricia G. Stelmacttowicz ◽  
Michael P. Gorga ◽  
John K. Cullen
Keyword(s):  
Frequency Response ◽  
Flat Plate ◽  
Tympanic Membrane ◽  
Sound Pressure Level ◽  
Potential Application ◽  
Sound Pressure ◽  
Calibration Procedure ◽  
Pressure Level ◽  
Frequency Dependent ◽  
Tympanic Membranes

A technique is described to estimate the sound pressure level developed by a broad frequency response transducer at the tympanic membrane. Real-ear probe tube measurements near the tympanic membranes of 10 subjects were used to obtain frequency-dependent correction values for a custom-designed flat-plate coupler. These latter measures can be used tot routine calibration of the transducer. Audiometric thresholds from 250 to 16000 Hz were obtained on 14 children (5–18 years).Threshold estimates were found to be comparable to previouslv reported values. Potential application and limitations of this technique are discussed.

Assessment of Impulse Noise Hazard and the Use of Hearing Protection Devices in Workplaces Where Forging Hammers are Used

2015 ◽  
Vol 39 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Rafał Młyński ◽  
Emil Kozłowski ◽  
Jan Adamczyk
Keyword(s):  
Sound Pressure Level ◽  
Impulse Noise ◽  
Sound Pressure ◽  
Noise Exposure ◽  
Pressure Level ◽  
Hearing Protection ◽  
Exposure Level ◽  
Limit Values ◽  
Noise Parameters ◽  
Protection Devices

Abstract The impulse noise is agent harmful to health not only in the case of shots from firearms and the explosions of explosive materials. This kind of noise is also present in many workplaces in the industry. The paper presents the results of noise parameters measurements in workplaces where four different die forging hammers were used. The measured values of the C-weighted peak sound pressure level, the A-weighted maximum sound pressure level and A-weighted noise exposure level normalized to an 8 h working day (daily noise exposure level) exceeded the exposure limit values. For example, the highest measured value of the C-weighted peak sound pressure level was 148.9 dB. In this study possibility of the protection of hearing with the use of earplugs or earmuffs was assessed. The measurement method for the measurements of noise parameters under hearing protection devices using an acoustical test fixture instead of testing with the participation of subjects was used. The results of these measurements allows for assessment which of two tested earplugs and two tested earmuffs sufficiently protect hearing of workers in workplaces where forging hammers are used.

Microphone Sensitivity as a Source of Variation in Nasalance Scores

1996 ◽  
Vol 39 (6) ◽  
pp. 1228-1231 ◽  
Author(s):  
David J. Zajac ◽  
Richard Lutz ◽  
Robert Mayo
Keyword(s):  
Frequency Response ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Stimulus Frequency ◽  
Pressure Level ◽  
Signal Source ◽  
Function Generator ◽  
Response Characteristics ◽  
Sources Of Variation ◽  
Frequency Response Characteristics

A two-part study was conducted to determine the sources of variation in nasalance scores derived from the Nasometer. In Study #1, a function generator was used as a signal source to calibrate and input sine and square waves directly into the Nasometer. Ten stimuli ranging from 105 to 330 Hz in 25 Hz increments were evaluated. In Study #2, the same signal source and an amplified loudspeaker were used to calibrate and present square waves to the Nasometer via five different sets of microphones. The sound pressure level of all stimuli was maintained at 88 dB. Each microphone set was calibrated using the 105 Hz signals. Results from Study #1 indicated consistent nasalance scores across all frequencies (i.e., all scores were within 2% of calibration). Results from Study #2 demonstrated deviations greater than 2% from calibration as a function of frequency for all five sets of microphones. The smallest deviation was 5%, whereas the largest deviation was 14%. We suggest that the variation in nasalance as a function of stimulus frequency may be due to a mismatch in the sensitivity of microphones (i.e., different frequency response characteristics). It is further suggested (a) that individual investigators determine the response characteristics of their microphones and (b) that relatively small variations in nasalance scores (i.e., 5–14%) either within or across speakers be interpreted with caution.

scholarly journals Construction of a Test Chamber for Human Infrasound Exposure

1982 ◽  
Vol 1 (3) ◽  
pp. 123-134 ◽  
Author(s):  
Henrik Møller
Keyword(s):  
Frequency Response ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Test Chamber ◽  
Pressure Level ◽  
Frequency Range ◽  
Infrasound Signal ◽  
Flat Frequency Response ◽  
Harmonic Distortions ◽  
Air Exchange

The report describes the construction of an infrasound test chamber, in which subjects can be exposed to controlled infrasound signals. The infrasound is produced by 16 electrodynamic loudspeakers, mounted in one wall of the 16 m3 chamber. The maximum sound pressure level that can be obtained is 125 dB rms in the frequency range 0.05 Hz–30 Hz. At a level of 120 dB the 2nd and 3rd harmonic distortions are below 1%. The system does not utilize any acoustical resonances, thus giving a flat frequency response. In this way it is possible to reproduce a real environmental infrasound signal recorded on tape. For the purpose of experiments of longer duration, the room is equipped with a ventilating system, which gives sufficient air exchange for 3 persons. When in use, this system increases the lower limiting frequency to 0.3 Hz.

scholarly journals Selection of Level-Dependent Hearing Protectors for Use in An Indoor Shooting Range

2019 ◽  
Vol 16 (13) ◽  
pp. 2266 ◽  
Author(s):  
Rafal Mlynski ◽  
Emil Kozlowski
Keyword(s):  
Sound Pressure Level ◽  
Impulse Noise ◽  
Sound Pressure ◽  
Pressure Level ◽  
Shooting Range ◽  
Noise Parameters ◽  
The People ◽  
Hearing Protectors ◽  
High Sound ◽  
Selection Of

The high sound pressure level generated by impulse noise produced in an indoor shooting range makes it necessary to protect the hearing of the people it affects. Due to the need for verbal communication during training at a shooting range, level-dependent hearing protectors are useful. The objective of this study was to answer the question of whether it is possible to properly protect the hearing of a shooting instructor using level-dependent hearing protectors. The noise parameters were measured in the places where the instructor was present at the shooting range. The division of a specific group of trained shooters into subgroups consisting of three or six simultaneously shooting individuals did not significantly affect the exposure of the shooting instructor to the noise. An assessment of noise reduction was carried out for eight models of earmuffs and two variants of earplugs, using computational methods for the selection of hearing protectors. Among the noise parameters, both the A-weighted equivalent sound pressure level and the C-weighted peak sound pressure level were taken into account. Depending on the assessment criterion adopted, a sufficient reduction in impulse noise was provided by either four or six out of the 10 hearing protectors included in the study.

Contributions of Voice and Nonverbal Communication to Perceived Masculinity–Femininity for Cisgender and Transgender Communicators

2020 ◽  
Vol 63 (4) ◽  
pp. 931-947
Author(s):  
Teresa L. D. Hardy ◽  
Carol A. Boliek ◽  
Daniel Aalto ◽  
Justin Lewicke ◽  
Kristopher Wells ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Vocal Tract ◽  
Presentation Mode ◽  
Pressure Level ◽  
Presentation Modes ◽  
Audiovisual Stimuli ◽  
Vocal Tract Resonance ◽  
Point Light

Purpose The purpose of this study was twofold: (a) to identify a set of communication-based predictors (including both acoustic and gestural variables) of masculinity–femininity ratings and (b) to explore differences in ratings between audio and audiovisual presentation modes for transgender and cisgender communicators. Method The voices and gestures of a group of cisgender men and women ( n = 10 of each) and transgender women ( n = 20) communicators were recorded while they recounted the story of a cartoon using acoustic and motion capture recording systems. A total of 17 acoustic and gestural variables were measured from these recordings. A group of observers ( n = 20) rated each communicator's masculinity–femininity based on 30- to 45-s samples of the cartoon description presented in three modes: audio, visual, and audio visual. Visual and audiovisual stimuli contained point light displays standardized for size. Ratings were made using a direct magnitude estimation scale without modulus. Communication-based predictors of masculinity–femininity ratings were identified using multiple regression, and analysis of variance was used to determine the effect of presentation mode on perceptual ratings. Results Fundamental frequency, average vowel formant, and sound pressure level were identified as significant predictors of masculinity–femininity ratings for these communicators. Communicators were rated significantly more feminine in the audio than the audiovisual mode and unreliably in the visual-only mode. Conclusions Both study purposes were met. Results support continued emphasis on fundamental frequency and vocal tract resonance in voice and communication modification training with transgender individuals and provide evidence for the potential benefit of modifying sound pressure level, especially when a masculine presentation is desired.

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