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Occupational Noise Calculators

Hearing Protection Calculator - HML Method

These calculators estimate the sound level at the ear when wearing hearing protection. The noise must be measured using a suitable sound level meter and the details of the hearing protectors in questions must be available too. There are three methods available:

  NRR Method The NRR (Noise Reduction Rating) method is usually the least accurate but easiest way to assess a hearing protector's performance. You need an "A" or "C" weighted sound level meter and the protector's NRR figure.
  HML Method The H-M-L method is usually the second most accurate method. You need a sound level meter that measures the "A" weighted and the "C" weighted Sound Level. You also need the protector's HML values.
  Octave Band This is the most accurate way to calculate the level at the ear. Use this if you have a sound level meter with Octave Band Filters. You also need the hearing protector's APV values.


    H M L  
Protector H-M-L
    LA   LC  
Sound Levels
  dB(A) dB(C)
Calculated Level


OSHA Noise Meters

Sound Level Meter
From $423.00
Integrating Logging Meter
From $855.00
Integrating with Peak
From $1562.00
Octave Band Noise Meter
From $2173.00

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