Noise Dosimetry measurements at an outdoor firing made in the ear canal and close to the ear

In-ear and On-body Measuremetns of Impulse Noise Exposure

In-ear dosimetry for high-level impulse noise presents significant challenges. External peak sound pressure levels (>140 dB SPL) combined with hearing protection can result in earcanal levels approaching 140 dB. MIT Lincoln Laboratory has developed a modified commercial-off-the-shelf recorder that simultaneously measures signals from both ear canal and just outside the ear at a sample rate of 96 kHz. Validation measurements were conducted with a GRAS 45CB fixture and an acoustic shock tube. An exploratory study was conducted with a small sample of experimenters during a recent Navy-sponsored noise survey conducted at Quantico Marine Corps Base. Results will be presented from the nominal instructor’s position as well as from bystanders observing at a firing range. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health. Mention of any company or product does not constitute endorsement by NIOSH.