Comments on "What is silence? Therefore, what is sound?" - A discussion of Brownian motion and the threshold of hearing (L).

This Letter to the editor is a comment on an article in the JASA Forum by William Yost. It pertains to a reference he made to prior work that indicates the possibility that the human threshold of hearing in the most sensitive region may be limited by Brownian motion of the air molecules, also called thermal noise. I present additional data and my own observations that support this contention.

Acoustic trauma from continuous noise: Minimum exposures, issues in clinical trial design, and comments on magnetic resonance imaging exposures.

Acoustic trauma (AT) is permanent hearing loss after a single noise exposure. A few human cases resulting from continuous, i.e.

Spectral analysis of hearing protector impulsive insertion loss.

Objective: To characterise the performance of hearing protection devices (HPDs) in impulsive-noise conditions and to compare various protection metrics between impulsive and steady-state noise sources with different characteristics.

Design: HPDs were measured per the impulsive test methods of ANSI/ASA S12.42- 2010 .

Speech recognition in noise under hearing protection: A computational study of the combined effects of hearing loss and hearing protector attenuation.

Objective: To investigate the effects of hearing protection on speech recognition in noise.

Design: Computational study using a speech recognition model that was previously empirically validated.

Study Sample: Recognition scores were calculated in unprotected and protected conditions for four sets of hearing protector attenuation functions in two different noises, for three simulated hearing profiles illustrative of those anticipated in the noisy workplace.

Measurement of impulse peak insertion loss from two acoustic test fixtures and four hearing protector conditions with an acoustic shock tube.

Impulse peak insertion loss (IPIL) was studied with two acoustic test fixtures and four hearing protector conditions at the E-A-RCAL Laboratory. IPIL is the difference between the maximum estimated pressure for the open-ear condition and the maximum pressure measured when a hearing protector is placed on an acoustic test fixture (ATF). Two models of an ATF manufactured by the French-German Research Institute of Saint-Louis (ISL) were evaluated with high-level acoustic impulses created by an acoustic shock tube at levels of 134 decibels (dB), 150 dB, and 168 dB.

Results of the National Institute for Occupational Safety and Health-U.S. Environmental Protection Agency interlaboratory comparison of American National Standards Institute S12.6-1997 Methods A and B.

The National Institute for Occupational Safety and Health and the Environmental Protection Agency sponsored the completion of an interlaboratory study to compare two fitting protocols specified by ANSI S12.6-1997 (R2002) [(2002). American National Standard Methods for the Measuring Real-Ear Attenuation of Hearing Protectors, American National Standards Institute, New York].

Development of a new standard laboratory protocol for estimation of the field attenuation of hearing protection devices: sample size necessary to provide acceptable reproducibility.

The mandate of ASA Working Group S12/WG11 has been to develop "laboratory and/or field procedure(s) that yield useful estimates of field performance" of hearing protection devices (HPDs). A real-ear attenuation at threshold procedure was selected, devised, tested for one earmuff and three earplugs via an interlaboratory study involving five laboratories and 147 subjects, and incorporated into a new standard that was approved in 1997 [Royster et al., "Development of a new standard laboratory protocol for estimating the field attenuation of hearing protection devices.

Hearing protection: surpassing the limits to attenuation imposed by the bone-conduction pathways.

With louder and louder weapon systems being developed and military personnel being exposed to steady noise levels approaching and sometimes exceeding 150 dB, a growing interest in greater amounts of hearing protection is evident. When the need for communications is included in the equation, the situation is even more extreme. New initiatives are underway to design improved hearing protection, including active noise reduction (ANR) earplugs and perhaps even active cancellation of head-borne vibration.