Impulse noise: Some definitions, physical acoustics and other considerations

Abstract

An overview of the impulse noise (blast wave) stimulus is presented with an emphasis on examining those parameters that have been traditionally used to quantify the stimulus for the purpose of understanding its effects on hearing.

The Research on Impulsive Events in Railway Noise Generated During Passage Through a Railroad Switch

“…(5) (Hamernik, Hsueh, 1991), where it is defined as the difference between peak sound pressure level, L Apeak and equivalent sound pressure level measured with a SLOW time constant L AeqS . Weak inequality can be described as a threshold for considering events as highly impulsive or even as impulses with high-energy content This standard proposes three types of impulsive sources:…”

Qualification Methods for Assessment of Annoyance of Impulsive Sounds

“…In accordance with the criteria (CHABA 1981, 1996, Henderson and Hamernik 1986, Hamernik and Hsueh 1991, all of the signals presented in the article should be treated as impulsive. Within close distance of the sound source, the useful parameters can be impulsiveness I and increase of sound level ΔL.…”

“…The two main features of an impulsive sound are: a very short duration, usually less than one second (ISO 19961:2003, ISO 1996-2:2007) and a high value of the peak sound pressure level (Henderson and Hamernik 1986, Hamernik and Hsueh 1991, ISO 1996-1:2003. These features considered as the basis for identifying the impulses do not allow us to classify these sounds unambiguously in terms of their harmful effects on humans or on the feeling of an acoustic annoyance (Wszołek 2015).…”

Assessment of the Applicability of ANSI S12.42-2010 as a General Measure of Protection from Impulsive Noise by Measurement of Impulsive and Continuous Noise Insertion Loss of the HGU-56/P and the CEP

“…The standard calls for the impulsive noise source used for testing to have an A-duration (initial positive pressure duration) of between 0.5 and 2 ms. Using the mathematical formula for an ideal Friedlander wave, the peak in spectral energy for such a noise source will be between approximately 320 and 80 Hz (Hamernik and Hsueh, 1991). If the peak insertion loss for an HPD is measured using a short duration wave, which has its spectral energy concentrated at higher frequencies (such as might be created by a rifle or pistol), the results may not represent the insertion loss for a longer duration wave (such as might be created by artillery or air-blasts from explosives).…”