Managing an "Own Voice" Problem That Has an Amplifier Origin

2005 ◽  
Vol 16 (10) ◽  
pp. 781-788 ◽  
Author(s):  
Francis Kuk
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Hearing Aid ◽  
Low Frequency ◽  
Pressure Level ◽  
Fine Tuning ◽  
Ear Canal ◽  
Frequency Sound ◽  
Tuning Process ◽  
Voice Problem

The complaint from hearing aid wearers of hollowness in the sound of their voice is typically associated with excessive low-frequency sound pressure level (SPL) in the ear canal. Increasing the vent diameter and/or reducing the gain in the low frequency would typically minimize this complaint. This paper reports on a case where the origin of hollowness was insufficient low-frequency gain compared to a previous hearing aid fitting. It describes the systematic process that was followed in uncovering the origin of the patient's hollowness complaint. Clinicians might follow a similar objective approach in their fine-tuning process to resolve wearer complaints.

Gyro Rock Crusher and Asphalt Plant Sound Power Levels

2012 ◽  
Author(s):  
Henry A. Scarton ◽  
Kyle R. Wilt
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Low Frequency ◽  
Pressure Level ◽  
Sound Power ◽  
Far Field ◽  
Atmospheric Attenuation ◽  
Frequency Sound ◽  
Sound Pressure Levels ◽  
Rock Crusher

Sound power levels including the distribution into octaves from a large 149 kW (200 horsepower) gyro rock crusher and separate asphalt plant are presented. These NIST-traceable data are needed for estimating sound pressure levels at large distances (such as occurs on adjoining property to a quarry) where atmospheric attenuation may be significant for the higher frequencies. Included are examples of the computed A-weighted sound pressure levels at a distance from the source, including atmospheric attenuation. Substantial low-frequency sound power levels are noted which are greatly reduced in the far-field A-weighted sound pressure level calculations.

Probe-Tube Microphone Measures of Vent Effects With In-the-Canal Hearing Aid Shells

1992 ◽  
Vol 1 (2) ◽  
pp. 58-62 ◽  
Author(s):  
Andrew Stuart ◽  
Robert Stenstrom ◽  
Odilia MacDonald ◽  
Mark P. Schmidt ◽  
Gail MacLean
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Hearing Aid ◽  
Low Frequency ◽  
Pressure Level ◽  
Frequency Responses ◽  
Upward Shift

The acoustic effects of three different configurations of vented in-the-canal (ITC) hearing aid shells were investigated. Real-ear sound pressure level measures (200–2000 Hz) were obtained from unvented and vented ITC shells from 12 adult subjects. In general, with increasing vent size, an increase in the amount of low-frequency reduction and an upward shift in vent kneepoints and vent-associated resonance occurred. The use of venting may be considered clinically for low-frequency reduction in ITC hearing aid frequency responses.

The Occlusion Effect in Bone Conduction Hearing

1965 ◽  
Vol 8 (2) ◽  
pp. 137-148 ◽  
Author(s):  
David P. Goldstein ◽  
Claude S. Hayes
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Bone Conduction ◽  
Pressure Level ◽  
Ear Canal ◽  
Significant Difference ◽  
Threshold Measure ◽  
Level Shifts ◽  
Positive Correlations ◽  
Occlusion Effect

This experiment tested the hypothesis that the occlusion effect is accompanied by an increase in sound pressure level in the external auditory canal. Pure tone bone conduction thresholds and sound pressure levels were measured, first with the ear canal open, then with the ear canal closed, at two positions of the bone vibrator and at five frequencies in 28 normal listeners. Statistical analyses revealed a significant difference between measures at 250, 500, and 1 000 cps but not at 2 000 and 4 000 cps. Average sound pressure level shifts tended to be larger than their threshold measure counterparts. The two measures, nevertheless, yielded positive correlations.

scholarly journals Noise-silencing technology for upright venting pipe jet noise

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401879481 ◽  
Author(s):  
Enbin Liu ◽  
Shanbi Peng ◽  
Tiaowei Yang
Keyword(s):  
Natural Gas ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Low Frequency ◽  
Jet Noise ◽  
Pressure Level ◽  
Living Environment ◽  
Frequency Noise ◽  
Frequency Range ◽  
Expansion Chamber

When a natural gas transmission and distribution station performs a planned or emergency venting operation, the jet noise produced by the natural gas venting pipe can have an intensity as high as 110 dB, thereby severely affecting the production and living environment. Jet noise produced by venting pipes is a type of aerodynamic noise. This study investigates the mechanism that produces the jet noise and the radiative characteristics of jet noise using a computational fluid dynamics method that combines large eddy simulation with the Ffowcs Williams–Hawkings acoustic analogy theory. The analysis results show that the sound pressure level of jet noise is relatively high, with a maximum level of 115 dB in the low-frequency range (0–1000 Hz), and the sound pressure level is approximately the average level in the frequency range of 1000–4000 Hz. In addition, the maximum and average sound pressure levels of the noise at the same monitoring point both slightly decrease, and the frequency of the occurrence of a maximum sound pressure level decreases as the Mach number at the outlet of the venting pipe increases. An increase in the flow rate can result in a shift from low-frequency to high-frequency noise. Subsequently, this study includes a design of an expansion-chamber muffler that reduces the jet noise produced by venting pipes and an analysis of its effectiveness in reducing noise. The results show that the expansion-chamber muffler designed in this study can effectively reduce jet noise by 10–40 dB and, thus, achieve effective noise prevention and control.

Using Average Correction Factors to Improve the Estimated Sound Pressure Level Near the Tympanic Membrane

2012 ◽  
Vol 23 (09) ◽  
pp. 733-750
Author(s):  
Karrie LaRae Recker ◽  
Tao Zhang ◽  
Weili Lin
Keyword(s):  
Tympanic Membrane ◽  
Sound Pressure Level ◽  
Hearing Aids ◽  
Best Practice ◽  
Sound Pressure ◽  
Pressure Level ◽  
Correction Factors ◽  
Ear Canal ◽  
Frequency Components ◽  
Ear Canals

Background: Sound pressure-based real ear measurements are considered best practice for ensuring audibility among individuals fitting hearing aids. The accuracy of current methods is generally considered clinically acceptable for frequencies up to about 4 kHz. Recent interest in the potential benefits of higher frequencies has brought about a need for an improved, and clinically feasible, method of ensuring audibility for higher frequencies. Purpose: To determine whether (and the extent to which) average correction factors could be used to improve the estimated high-frequency sound pressure level (SPL) near the tympanic membrane (TM). Research Design: For each participant, real ear measurements were made along the ear canal, at 2–16 mm from the TM, in 2-mm increments. Custom in-ear monitors were used to present a stimulus with frequency components up to 16 kHz. Study Sample: Twenty adults with normal middle-ear function participated in this study. Intervention: Two methods of creating and implementing correction factors were tested. Data Collection and Analysis: For Method 1, correction factors were generated by normalizing all of the measured responses along the ear canal to the 2-mm response. From each normalized response, the frequency of the pressure minimum was determined. This frequency was used to estimate the distance to the TM, based on the ¼ wavelength of that frequency. All of the normalized responses with similar estimated distances to the TM were grouped and averaged. The inverse of these responses served as correction factors. To apply the correction factors, the only required information was the frequency of the pressure minimum. Method 2 attempted to, at least partially, account for individual differences in TM impedance, by taking into consideration the frequency and the width of the pressure minimum. Because of the strong correlation between a pressure minimum's width and depth, this method effectively resulted in a group of average normalized responses with different pressure-minimum depths. The inverse of these responses served as correction factors. To apply the correction factors, it was necessary to know both the frequency and the width of the pressure minimum. For both methods, the correction factors were generated using measurements from one group of ten individuals and verified using measurements from a second group of ten individuals. Results: Applying the correction factors resulted in significant improvements in the estimated SPL near the TM for both methods. Method 2 had the best accuracy. For frequencies up to 10 kHz, 95% of measurements had <8 dB of error, which is comparable to the accuracy of real ear measurement methods that are currently used clinically below 4 kHz. Conclusions: Average correction factors can be successfully applied to measurements made along the ear canals of otologically healthy adults, to improve the accuracy of the estimated SPL near the TM in the high frequencies. Further testing is necessary to determine whether these correction factors are appropriate for pediatrics or individuals with conductive hearing losses.

Control of hearing-aid saturated sound pressure level by frequency-shaped output compression limiting

1999 ◽  
Vol 28 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Hugh J. McDermott ◽  
Michelle R. Dean ◽  
Harvey Dillon
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Hearing Aid ◽  
Pressure Level

Suprathreshold Auditory Adaptation in Normal and Pathologic Ears

1968 ◽  
Vol 11 (2) ◽  
pp. 268-278 ◽  
Author(s):  
Fred Harbert ◽  
Betty Goldman Weiss ◽  
Chester R. Wilpizeski
Keyword(s):  
Sound Pressure Level ◽  
Clinical Setting ◽  
Sound Pressure ◽  
Diagnostic Information ◽  
Pressure Level ◽  
Balance Method ◽  
Sensation Level ◽  
Frequency Sound ◽  
Auditory Adaptation ◽  
Consistent Relationship

The Wood delayed loudness balance method was studied in normal and pathologic ears to determine the characteristics of suprathreshold auditory adaptation in three groups of subjects. No consistent relationship could be established between the amount and direction of the loudness change with the frequency, sound pressure level, or sensation level of the adapting signal. Suprathreshold adaptation, as measured by the Wood method, does not provide sufficient diagnostic information to be useful in a clinical setting.

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