Daniel Wayne Mauney

Earplug and hearing devices formed in-situ

A custom-molded earplug (18) for swimming protection, hearing protection, and the like, is fabricated in situ by depositing a foaming material (14 or 24) within a persons ear (10 or 42) and allowing the foaming material to form foam (16 or 44). Acoustic and electronic equipment such as a Helmholtz resonator or other tuned device capable of modifying sound waves, a communications transmitter, a communications receiver, a communications transceiver, a hearing aid, an ear microphone, a personal earphone, and a hearing test transducer or probe tube can be fabricated in the ear in a similar fashion. Temperature sensing elements may also be incorporated within or positioned by the foaming material to provide an in the ear thermometer.

Custom‐fitting earplug formed in situ using foaming action

A custom-fitting earplug (18) for hearing protection or other ear applications, or in-ear communications device mounting (40) is fabricated in situ by depositing a foaming material (14 or 24) within the persons ear (10 or 42, respectively) and allowing the foaming material (14 or 24) to expand therein to form foam (16 or 44, respectively). By applying slight pressure from outside the persons ear (10 or 42) through the stem (13) and/or keeper (11) during expansion, the foam (16 or 44, respectively) will be tightly packed in and conform to the ear canal. An optional sheath (15 or 36) positioned over the foaming material (14 or 24, respectively) serves to provide a smooth outer surface for the earplug (18) or communications device (40) produced and can aid in defining and limiting the expansion of the foam (14 or 24, respectively).

Sound Field Diffusivity and Reverberation Effects on the Real-Ear Attenuation of Hearing Protectors with Implications for Test Standards

A psychophysical experiment was conducted to determine the effects of different acoustic characteristics of the testing environment on the attenuation of earmuffs as measured using a standard real-ear attenuation at threshold (REAT) protocol. Three earmuffs were tested in four different sound fields. At one extreme, the testing environment was diffuse and reverberant as specified in ANSI

The Importance of Sound-Field Acoustic Specification for Hearing Protector Performance Measurement

3.19-1974 and CSA Z94.2-M1984. At the other extreme, a diffuse sound field was established within an anechoic chamber fulfilling ANSI S12.6-1984, ISO 4869-1: 1990, and SS 882151 (1981). Two intermediate conditions progressively degraded the diffusivity of the reverberant environment by reducing the reverberation time within the test room and increasing the directionality of the sound field. Small but statistically-significant attenuation differences resulted from the sound field realization techniques allowed by the two sets of standards. Also, significant differences occurred between the most directional sound field and the most diffuse, reverberant sound field. Application of these results must depend upon the purpose of the testing. For hearing protector test standards development, hearing protector research, and product labeling, the statistically significant differences should be considered before making direct comparisons of test results obtained in different sound fields. However, for many other applications, the differences are probably not of practical significance. For instance, any of the test environments can be used to obtain a reasonable estimate of the protection level that an earmuff is providing an individual under controlled laboratory conditions.

Earmolds for two-way communications devices

Several real-ear attenuation at threshold (REAT) standards govern the attenuation testing of hearing protectors internationally. A characteristic common to many is the requirement of a diffuse sound field and the toleration of a wide range of reverberation times, allowing testing in an anechoic or a reverberant test room. This study explored the degree to which the diffuse environment can be degraded without significantly affecting the attenuation tested under ANSI S3.19-1974. In addition, the study compared a diffuse sound field generated in a reverberant room (as required by ANSI S3.19-1974 and CSA Z94.2-M1984) with a diffuse sound field generated in an anechoic room (as allowed by ANSI S12.6-1984, BSI 5108:1983, ISO 4869-1(E):1990, and SS 882151). Results indicate that degrading the diffusivity will result in statistically significant changes in attenuation, but the magnitude of change is small. In addition, small but significant differences exist between the two test chambers. Interpretation of these results depends upon the purpose of the testing. For applications where accuracy is critical, the statistically significant differences should not be ignored. However, for noncritical applications, such as simply predicting the amount of attenuation a particular worker is receiving with a specific hearing protector, the small magnitude of these differences do not preclude the use of these alternative environments. Therefore, actual protection levels achieved in the field can be empirically verified in either sound field.