I sometimes attend events with very loud music, e.g. Technoparade (> 110dB next to speakers) and at times need to stop listening the music, without having to move. How can I achieve maximum hearing protection?
Currently I use a combination of:
- custom-fitted earplugs (mirror) (~30 dB Noise Reduction Rating (NRR)(mirror) for the most protective ones): for that maximum hearing protection, I don't use custom-fitted, flat-response attenuators but instead use custom-fitted earplugs designed to sleep, as I believe the latter provide higher noise/music reduction.
- ear muffs or noise cancelling headphones (~33 dB NRR for the most protective ones).
How can I improve on that? I can't find (mirror) custom-fitted earplugs or earmuffs that offer more than ~30 dB reduction, unless I missed something, otherwise perhaps could I add a third level of protection (if so, what)?
The equipment used to protect hearing does not reduce the decibel levels within a given environment by the precise decibel number that is tied to the NRR for that device. For example, a person who is working in a loud occupational environment may be exposed to noise as great as 100 decibels. If an individual is wearing hearing protection equipment with an NRR of about 30 decibels, the noise exposure amount would not be lowered to 70 decibels. Instead, it would be lowered to 88.5 decibels. Take a look at the following steps taken to determine the level of noise exposure after reduction:
- Subtract seven from the NRR number, which is given in decibels.
- Divide the result by two.
- Subtract the result from the original noise exposure level in decibels.
which means using a custom-fitted earplugs with 30 dB reduction and earmuffs with 33 dB Noise Reduction Rating (NRR) doesn't result in the Technoparade music being reduced from 110dB to 53dB (=110-30-33): instead, the music will be heard at a dB higher than 53. One may use some online hearing protection calculator to compute the actual dB reduction given the NRR and speaker dB. Also, note that for most wearers, the NRR identified on the current EPA label significantly overestimates the protection of the hearing protector in the workplace (mirror).