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About this tool
Compare NRR, SNR and flat musician filter ratings and see the protected level and safe exposure time for a gig at any loudness.
Hearing protectors are labelled with a Noise Reduction Rating (NRR) in the United States, a Single Number Rating (SNR) in Europe, or a flat attenuation figure for musician filters — and the three are applied to a noise level in different ways. This guide converts whichever number is on your packet into the level actually reaching your ear: it subtracts the 7 dB A-weighting correction from an NRR and then applies the NIOSH real-world derating (25% for earmuffs, 50% for foam plugs, 70% for other plugs), subtracts SNR from the C-weighted level, and subtracts a flat filter figure directly. It then compares the protected level against the NIOSH limit of 85 dB(A) for 8 hours with a 3 dB exchange rate.
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Enter "Venue level, dB(A)" — or tap one of the 85, 95, 100, 105 and 110 dB chips — and "Time at the venue (minutes)".
Set "Rating system on the packet" to NRR (US label), SNR (EU label) or Flat musician filter and type the packet figure; NRR then asks for "Protector type (sets the NIOSH derating)" — Earmuffs 25%, Foam / formable earplugs 50%, Pre-moulded, custom or banded plugs 70% — and SNR for the "Assumed C minus A offset (dB)".
Read "Level reaching your ear" in dB(A) with the real-world reduction, plus rows for the label reduction, the NIOSH derated rating, safe time with and without protection and the noise dose percentages against the 85 dB(A) limit; "Copy result" copies the lot.
Applies the NIOSH derating so the figure reflects the fit people actually get, not laboratory conditions.
NRR, SNR and flat musician filter ratings in one place, each with its own correct method.
Shows the safe duration before and after protection, so the answer is a plan and not just a decibel number.
At a typical 100 to 105 dB(A) gig, look for roughly 15 to 20 dB of real-world reduction. A foam plug labelled NRR 33 gives about 9.5 dB after the 7 dB correction and the 50% NIOSH derating, so a well-fitted plug or a 20 dB flat filter is the more honest choice for front-of-stage positions.
Neither is better protection — they are different labelling standards. NRR (US, ANSI S3.19) is subtracted from an A-weighted level after a 7 dB correction; SNR (EU, EN ISO 4869-2) is subtracted from the C-weighted level. SNR figures generally look a few decibels higher than the NRR for the same product because of how each is measured.
Live amplified music commonly measures 95 to 105 dB(A) on the floor and can reach 110 dB(A) at the barrier of a festival main stage. At 105 dB(A) the NIOSH exposure limit is reached in under five minutes, which is why unprotected attendance at a full set is well over the daily dose.
Less than foam does. Foam plugs attenuate high frequencies far more than low ones, which is what makes music sound muffled and bass-heavy. Filtered musician earplugs are designed for roughly even attenuation across the spectrum — typically 15, 20 or 25 dB — so the balance of the mix survives while the level drops.