Percussion instruments in small practice rooms present enough noise exposure to be dangerous according to NIOSH levels, meaning that hearing protection would be recommended in such situations. Musicians often report that hearing protection makes it difficult to hear and interpret musical sounds, and many manufacturers have therefore developed universal-fit earplugs meant to attenuate sound more uniformly than traditional industrial-use earplugs. The narrowband and impulsive nature of percussion sounds, however, make them particularly susceptible to frequency-specific variation in attenuation for any given earplug. In order to quantify these effects, frequency-specific insertion loss measurements were taken in practice rooms using a KEMAR test fixture for seven earplug models and six percussion instruments. Results illustrate that the attenuation for a given instrument is very consistent across all earplugs, but that for specific earplugs the attenuation of each instrument can be very different from the NRR and is most related to the frequency band where the energy lies for the instrument. For percussion applications, frequency-specific attenuation characteristics can therefore be useful in choosing an earplug to match the instrument.
Weidman et al. (Wed,) studied this question.