Custom Hearing and Noise Protectors

Custom Hearing Protection
Earplugs
Noise
Recreational Plugs for Specific Applications

Custom Hearing Protection

  • Advantages of Custom Hearing Protection.
  • Custom-made hearing protection inserts are manufactured to fit individual ears, providing repeatable performance, consistent protection and increased comfort for longer periods of time.
  • They are available in a variety of medical-grade silicone and vinyl materials to reduce irritation of sensitive ears.
  • Custom products are designed for several years of reliable use.  Long life results in low cost per individual per day.
  • Custom Hearing Protection Considerations.
  • For maximum protection, “full-shell” style protectors are recommended.
  • Filtered sound plugs provide less noise attenuation than solid plugs.
  • Sound attenuator ear plugs and ER-9/15/25 musicians’ plugs may not be suitable for conditions of higher noise levels or increased exposure times.
  • Custom hearing protectors are designed to fit in the ear in only one way.  Right/left identification dots or designators are available on all custom products.
  • If plugs are used in combination with ear muffs, use hearing protectors with recessed removal handles or sound plugs without removal handles. Removal handles may disturb the seal between the skin and the muffs.
  • Care and Maintenance of Custom Hearing Protection Products.
    • Custom hearing protectors should be cleaned of cerumen (ear wax) and dirt after each use.
    • Rubbing alcohol and harsh detergents can harden and yellow soft ear plug materials.  Use a damp cloth for longer life.
    • Hearing protectors and sound plugs can be cleaned with a cloth dampened with water.
    • Sound or ear plugs with a non-removable filter should be wiped clean with a dry cloth.
      ER-9/15/25 musicians’ plugs are designed with a detachable attenuator button filter.  Remove the button prior to cleaning with water or a damp cloth.  Allow to dry before replacing the button.

Earplugs

Problems with Conventional Earplugs.

  • Problem 1.  Existing earplugs attenuate much more than necessary for much of the noise in industry and the environment.
  • Problem 2 .  Regardless of their exact construction, existing earplugs produce 10- to 20-dB of high-frequency attenuation, resulting in their rejection because people can’t hear speech clearly.
  • Problem 3 .  Existing earplugs make the wearer’s own voice sound hollow (known as the occlusion effect).
  • Problem 4 .  Many people risk their hearing by either wearing earplugs loosely or by wearing no protection at all so they can hear voices, machinery or music more clearly.

Theory and Design of a Flat-Response “High-Fidelity” Earplug

The ER-series of custom-fit hearing protectors provide equal attenuation at all frequencies, allowing the wearer to hear sound naturally and clearly, but at a lower, SAFER sound level.  The ER-series of earplugs alleviate complaints associated with conventional earplugs, such as the occlusion effect, “dullness” of sound and over-attenuation of volume. Four levels of attenuation are available:

  • ER-9 provides approximately 9-dB of attenuation.
  • ER-15 provides approximately 15-dB of attenuation.
  • ER-20 provides approximately 20-dB of attenuation.
  • ER-25 provides approximately 25-dB of attenuation.

A flat-response, high-fidelity earplug must have a frequency response that follows the shape of the natural frequency response of the open ear but at a reduced level.  The ER-9, ER-15 and ER-25 earplugs use a diaphragm, similar to a passive speaker cone, to achieve the desired response curve.  The ER-20 earplug is a stock (non-custom) product that uses a tuned resonator and acoustic resistor to create a high-fidelity response.  To reduce the occlusion effect– in which the wearer’s own voice sounds hollow and unpleasant– a seal of the plug in the second bend of the ear canal (deep in the ear canal) is necessary.

In general, ER-15 protectors are designed for environments where the A-weighted sound pressure level is 105 dB or lower.  ER-25 protectors are designed for use in environments above 105 dB and below 120 dB.  The attenuation shown in the above graph is for an average ear. When put properly in place, ER-15 protectors will provide a minimum of 10 dB of attenuation, ER-20 protectors will provide a minimum of 15 dB of attenuation  and ER-25 protectors will provide a minimum of 20 dB of attenuation.
The ER-series of earplugs is designed for protection, comfort, and high-fidelity.

Noise

How Much Noise is Too Much?

Noise Level Chart

dBA Example Home & Yard Appliances Workshop & Construction
0 healthy hearing threshold
10 a pin dropping
20 rustling leaves
30 whisper
40 babbling brook computer
50 light traffic refrigerator
60 conversational speech air conditioner
70 shower dishwasher
75 toilet flushing vacuum cleaner
80 alarm clock garbage disposal
85 passing diesel truck snow blower
90 squeeze toy lawn mower arc welder
95 inside subway car food processor belt sander
100 motorcycle (riding) handheld drill
105 sporting event table saw
110 rock band jackhammer
115 emergency vehicle siren riveter
120 thunderclap oxygen torch
125 balloon popping
130 peak stadium crowd noise
135 air raid siren
140 jet engine at takeoff
145 firecracker
150 fighter jet launch
155 cap gun
160 shotgun
165 .357 magnum revolver
170 safety airbag
175 howitzer cannon
180 rocket launch
194 sound waves become shock waves

Noises over 140 dB cause PAIN. Exposure to noises over 90 dB harms hearing.

Safe Exposure Levels
Noise induced hearing loss is a function of three factors:

  • Exposure time.
  • Average noise level.
  • Peak level of very loud sounds.

Some people seem to be more susceptible to hearing loss than others, so that protection on the basis of an average time and average sound level exposure will protect only the “average” person.  The table below provides allowable safe exposure for sound using both the conservative “equal energy” approach and the U.S. Occupational Safety and Health Administration (OSHA) standard.  This table is based on a conservative assumption of the amount of attenuation provided by various custom high-fidelity ear protectors.  In other words, in most ears:

  • ER-9 protectors will provide a minimum of 5dB of attenuation.
  • ER-15 protectors will provide a minimum of 10 dB of attenuation.
  • ER-20 protectors will provide a minimum of 15 dB of attenuation.
  • ER-25 protectors will provide a minimum of 20 dB of attenuation.

Average Safe Hours per day

PERMISSIBLE NOISE EXPOSURES

Duration per day, hours | Sound level dBA slow response

____________|_______________

8………………………|                    90

6………………………|                    92

4………………………|                    95

3………………………|                    97

2………………………|                   100

1 1/2 ………………….|                 102

1………………………|                   105

1/2 ……………………|                 110

1/4  or less…………….|              115

Failure to protect hearing can result not only in noise-induced hearing loss, but it can also result in tinnitus .  Click here for more specific information on noise-induced tinnitus .

Recreational Plugs for Specific Applications

Music Industry
Musician ear plugs
In-ear earphone monitors
Aircraft
Headsets with tube and bar
Communications
Security earmolds
Custom in-ear monitors
Hunters / Shooters
Solid ear plugs
Sonic II ear plugs
Sound Scopes
Swimmers
Floatable ear plugs
Motor Sports
Solid ear plugs
Filtered ear plugs
Medical
Anesthesiology ear molds
Construction / Industry
Solid ear plugs
Filtered ear plugs
Sonic II ear plugs
Ear muffs