Editing Earplug (section)

==Types and use cases==
The diameter of the ear canals can be from 3 to 14 mm. They can be round, elliptical, and even slit-like. The ear canals may be straight, but more often curved to varying degrees. The shape and size of the right and left ear canals for the same worker '''can''' vary significantly.<ref name="Sataloff-1993">{{cite book |last1=Sataloff |first1=Joseph |last2=Michael |first2=Paul L. |last3=Vassalio |first3=Lawrence A. |editor1-last=Sataloff |editor1-first=Robert Thayer |editor2-last=Sataloff |editor2-first=Joseph |title=Occupational Hearing Loss |date=1993 |publisher=Marcel Dekker, Inc |location=New York, Basel, Hong Kong |isbn=0-8247-8814-1 |page=418 |edition=2nd, revised and expanded |url=https://archive.org/details/occupationalhear0000sata |access-date=11 August 2023 |chapter=14. Hearing Protectoors (Ear Canals and Earplugs)}}</ref> Installing the earplugs neatly and tightly (without gaps) can be a difficult task. 

Since the [[Hearing protection fit-testing|fitting of the earplugs]] greatly affects their noise attenuation,<ref name="AIHA-6-12" /> various designs of these personal protective equipment have been developed.

===Simple earplugs===
[[File:Disposable foam earplugs.jpg|thumb|left|Disposable foam earplugs: with coins for scale (top) and inserted into the wearer's ear.]]Basic foam style earplug protection is often worn by industrial workers who work within hearing distance of [[Industrial noise|loud machinery]] for long periods of time, and is used by the British [[Ministry of Defence (United Kingdom)|Ministry of Defence]] (MoD) for [[soldier]]s to use when firing weapons. Earplugs are rated for their ability to reduce noise; see {{section link||Rating}}.

[[File:Earplugs instructions2.jpg|thumb|Earplugs with instructions for use]]
[[File:Musicians orange plugs.jpg|thumb|Flanged earplugs made from silicone rubber. The hole in the left plug is the input port and extends as far as the central flange where the attenuation occurs.|alt=]]

Most disposable earplugs are elastic ones made of [[memory foam]], that is typically rolled into a tightly compressed cylinder (without creases) by the user's fingers and then inserted in the ear canal. Once released, the earplug expands until it seals the canal, blocking the sound vibrations that could reach the [[eardrum]]. Other disposable plugs simply push into the ear canal without being rolled first. Sometimes earplugs are connected with a cord to keep them together when not in use. Other common material bases for disposable earplugs are viscous [[wax]] or [[silicone]].

Other devices that provide hearing protection include electronic devices worn around and/or in the ear, and are designed to cancel out the loud noise of a gunshot, while possibly amplifying quieter sounds to normal levels. While rich in features, these electronic devices are more expensive, compared to their foam counterparts.

In other activities, hobby [[motorcyclist]]s and [[skier]]s may also choose to use decibel reduction earplugs, to compensate for the ongoing noise of the wind against their head or helmet.

===  Musician's earplugs ===
[[File:Musicians earplugs.jpg|thumb|Musician's earplugs. The grey end caps contain an acoustic transmission line with a damper (attenuator) at the end while the domed flanges form a seal in the ear canal. The output port can just be seen as a small hole at the near end of the left plug.]]

Musicians are exposed to potentially harmful levels of sound, which can lead to [[hearing loss]], tinnitus, and other auditory symptoms. Because of this, musicians may choose to use earplugs.

Musician's earplugs (also called Hi-Fi or Lossless earplugs{{CN|date=November 2023}}) are designed to [[attenuate]] sounds evenly across all frequencies (pitches) which helps maintain the ear's natural frequency response and thus minimizes the effect on the user's perception of [[timbre]] (frequency spectrum, f.ex. [[Bass (sound)|bass]] and [[Treble (sound)|treble]] levels). These are commonly used by musicians and technicians, both in the studio and in concert, to avoid overexposure to high volume levels. Musician's earplugs generally achieve a more natural frequency response by incorporating a small [[Diaphragm (acoustics)|diaphragm]] or membrane together with acoustic channels and damping materials.<ref name=":2">{{Cite web|date=2019-11-19|title=Musicians and Music Industry|url=https://www.audiology.org/publications/guidelines-and-standards/musicians-and-music-industry|access-date=2020-10-18|website=Audiology|language=en|archive-date=2020-10-22|archive-url=https://web.archive.org/web/20201022185035/https://www.audiology.org/publications/guidelines-and-standards/musicians-and-music-industry|url-status=dead}}</ref> Simpler variants with only a small hole introduce a low frequency leak, and will not achieve a flat frequency response. Examples of manufacturers of membrane-based earplugs are ACS, Etymotic and [[Minuendo]].

Preformed earplugs, such as the ER-20 earplug are universal (non-custom) earplugs with a noise reduction rating (NRR) of about 12&nbsp;dB. A selection of musician's earplugs have been reviewed by the National Acoustic Laboratories and The HEARing CRC in conjunction with [[Choice (Australian consumer organisation)|Choice]].<ref>[https://www.nal.gov.au National Acoustic Laboratories]</ref><ref>[https://www.hearingcrc.org The HEARing CRC]</ref> The review results (which include attenuation measures and user ratings of comfort, fit and sound quality) are available at What Plug?.<ref>[https://hearsmart.org/earplugs/what_plug/ What Plug?]</ref>

A more expensive option is the [[#Custom molds|custom molded]] musician's earplug, which is custom-made for the individual listener. These earplugs are typically made out of silicone or vinyl materials and come with a vent and a variety of filters that can change the amount of attenuation provided. Common static filter attenuation levels are 9, 15, and 25&nbsp;dB.<ref name=":1">{{Cite book|title=Hearing conservation in occupational, recreational, educational, and home settings|last=Vishakha|first=Rawool|publisher=Thieme|year=2012|isbn=9781604062564|location=New York|pages=201–219}}</ref> This type of plug is quite popular among [[audio engineer]]s who can safely listen to loud mixes for extended periods of time. However, they can be quite costly, being intended for constant re-use unlike simple earplugs which are disposable.

[[File:Elacin (R) ER-25 - musician Earplug worn.JPG|thumb|Custom earplugs worn by professional musicians]]
[[File:Metalmania 2007 - Sepultura - Derrick Green 01.jpg|thumb|Lead singer of the metal band [[Sepultura]] [[Derrick Green]] wearing a custom earplug]]

Alternately, musicians may use [[in-ear monitors]], which are essentially [[headphone]]s that also serve as earplugs by attenuating surrounding sound. In order for in-ear monitors to double up as hearing protection, custom earpieces should be used. The process for having custom earpieces made is similar to that of the custom musician's earplug and, similarly, the earpiece will be made of silicone or vinyl. While using an in-ear monitor can help protect hearing, the amount of protection provided by the monitor depends on the listening level that the musician chooses. Because of this, if the musician sets the monitor to a high level, the monitor may attenuate surrounding sound while still providing a potentially harmful level of sound directly to the musician's ear and therefore no longer serve a protective function.<ref name=":1" />

Several earplugs on the market claim to be for musicians, but are not in fact by definition a musician's earplug. By having a thin acoustical bypass channel, they allow for a slightly better frequency response and lower attenuation than simple earplugs, but far from the level of fidelity that membrane-based earplugs provide. These types of earplugs do not provide the flat attenuation that is characteristic of a musician's plug, but may still be useful for some, due to their lower price points.<ref name=":1" />

===Custom molds===
Earplugs can be molded to fit an individual's ear canal. This costs more, but can improve fit for the few percent that have an ear anatomy outside the norm.<ref>{{Cite web|url=https://www.linkedin.com/pulse/custom-molded-earplugs-myths-truths-tom-alexander-trones/|archive-url=https://web.archive.org/web/20190702124130/https://www.linkedin.com/pulse/custom-molded-earplugs-myths-truths-tom-alexander-trones/|archive-date=2019-07-02|title=Custom Molded Earplugs - The Myths and Truths|date=2019-07-02|access-date=2019-07-02}}</ref>

Custom molded earplugs fall into two categories: Laboratory made and Formed in Place. Laboratory made requires an impression to be made by a professional of the ear canal and outer ear. The impression is sent to a laboratory to be checked and made into a hearing protector. Formed in place uses the same process to make an impression of the ear canal and outer ear and then turns that impression into the protector. Both types of custom molded earplugs are non-disposable with the laboratory made typically lasting for 3 – 5 years and the formed in place lasting for 1 – 2 years.

For the best attenuation and proper fit, the impressions for custom molds must meet a desired criteria by the manufacturer of the mold. Before an impression can be taken for the custom mold the ear canal is checked for any wax or physical abnormalities. This is important in making sure there is a proper seal with the impression material and also not to push any wax deep into the canal. The otoblock (made with foam or cotton) will be inserted deep in the canal to prevent the impression material from going too far. The impression material (either silicone or powder/liquid) will be placed into the ear canal. This will need to be fully made, making sure there are no gaps or creases in the impression. If there are, then the mold made from the impression will not adequately seal the ear canal.  Once the custom mold is made, it will need to be inspected by the Audiologist for proper fit on the patient.  Hearing protection should also be verified using real-ear methods to ensure proper attenuation.  Real-ear attentuation at threshold (REAT) measurements test how narrowband noises of varying frequency are attenuated with and without the custom mold in place.  Testing for low-frequency attenuation can help to verify the earmold fit while testing high-frequency attenuation can verify the properties of the filter used.<ref name=":22"/><ref name=":2" />

For best results they are molded in the ear while in the position that they will be used. For instance, if they are to be used for sleeping then they should be molded in the ear while lying down, as different positioning of the jaws causes significant changes to the form of the ear canal, mostly a reduction of the diameter, risking the sleep earplug to be made too large otherwise. It is also important that during the impression process that a music performer use their [[embouchure]] or move the jaw to mimic singing in order to account for ear canal changes during performance. Therefore, if the impression is not properly constructed, then it will need to be redone.<ref name=":2" /> These changes can be felt by feeling with a finger just at the entrance to the ear canal while moving the jaws sideways, up and down or [[anterior and posterior]].

Most molded earplugs are made from silicone but other materials may be used, including thermoplastics,<ref name="zenplugs">{{cite web|url=http://www.zenplugs.com/molded-earplugs |title=ZenPlugs Custom Moulded Earplugs |publisher=Zenplugs.com |access-date=2013-06-22}}</ref> plastic, nylon <ref name="Serenity Earplugs">{{cite web|url=https://www.phonak-communications.com/en/products/hearing-protection/serenity-sp |title=Phonak Serenity SP Custom Molded Earplugs |publisher=Phonak.com |access-date=2019-04-18}}</ref> and even 3-D printed earplugs.

===Electronic earplugs===
The noise reduction of passive earplugs varies with frequency but is largely independent of level (soft noises are reduced as much as loud noises). As a result, while loud noises are reduced in level, protecting hearing, it can be difficult to hear low level noises. Active electronic earplugs exist, where loud noises are reduced more than soft noises, and soft sounds may even be amplified, providing [[dynamic range compression]]. This is done by having a standard passive earplug, together with a microphone/speaker pair (microphone on outside, speaker on inside; formally a pair of [[transducer]]s), so sound can be transmitted without being attenuated by the earplug. When external sounds exceed an established threshold (typically 82 dBA SPL), the amplification of the electronic circuit is reduced.  At very high levels, the amplification is turned off automatically and you receive the full attenuation of the earplug just as if it were turned off and seated in the ear canal.  This protects hearing, but allows one to hear normally when sounds are in safe ranges – for example, have a normal conversation in a low-noise situation, but be protected from sudden loud noises, for example at a construction site or a while hunting.

===Nonlinear earplugs===
Nonlinear earplugs provide similar advantages to electronic earplugs but do not require electricity. They are designed with a thin diaphragm which allows the amount of noise reduction to increase in proportion to the sound level to which the wearer is exposed.<ref>{{cite web |title=#234 Hearing Protection for Impulse Noise |url=https://multimedia.3m.com/mws/media/1087488O/hearing-protection-for-impulse-noise-technical-bulletin.pdf |website=multimedia.3m.com |publisher=3M Personal Safety Division}}</ref> This makes them useful for applications where situational awareness is required but noise protection is also necessary, such as the military or police.

===Sleep===
Earplugs for sleeping are made to be as comfortable as possible while blocking external sounds that may prevent or disrupt sleep. Specialized earplugs for such noises as a partner's [[snoring]] may have sound-dampening enhancements that enable the user to still hear other noises, such as an alarm clock.<ref name="alpine">[http://www.alpine.nl/EN/consumer_sleeping.htm Alpine] {{Webarchive|url=https://web.archive.org/web/20110724143539/http://www.alpine.nl/EN/consumer_sleeping.htm |date=2011-07-24 }} - Sleepsoft earplugs</ref>

To determine the comfort of earplugs used for sleeping, it is important to try them on while actually lying down. The pressure on the ear between the head and pillow may cause significant discomfort. Furthermore, just tilting the head back or to the side causes significant anatomical changes in the ear canal, mostly a reduction of the ear canal diameter, which may reduce comfort if the earplug is too large. Earplugs for sleeping may enhance recovery after major surgery. 
<ref name=Menger2018>{{cite journal| title = Earplugs during the first night after cardiothoracic surgery may improve a fast-track protocol.| author = Menger J.|author2= Urbanek B. |author3= Skhirtladze-Dworschak K.| doi = 10.23736/S0375-9393.17.11758-X| pmid = 28726359| journal =  Minerva Anestesiologica| year = 2018| volume =84| issue = 1| pages =49–57}}</ref>

===Protection from water===
Some earplugs are primarily designed to keep water out of the ear canal, especially during swimming and water sports. This type of earplug may be made of wax or moldable silicone which is custom-fitted to the ear canal by the wearer.

Exostosis, or [[surfer's ear]], is a condition which affects people who spend large amounts of time in water in cold climates. In addition, wind may increase the prevalence of the amount of exostosis seen in one ear versus the other dependent on the direction it originates from and the orientation of the individual to the wind.<ref name="King">{{cite journal|last=King|first=John F.|year=2010|title=Laterality of Exostosis in Surfers Due to Evaporative Cooling Effect|journal=Otology & Neurotology|volume=31|issue=2|pages=345–351|doi=10.1097/MAO.0b013e3181be6b2d|pmid=19806064|s2cid=205754007|display-authors=etal}}</ref> Custom-fitted surfer's earplugs help reduce the amount of cold water and wind that is allowed to enter the external ear canal and, thus, help slow the progression of exostosis.

Another condition is [[otitis externa]], which is an infection of the outer ear canal. This form of infection differs from those commonly occurring in children behind the eardrum, which is otitis media, or a middle ear infection. This infection's symptoms include: itchiness, redness, swelling, pain upon tugging of the pinna, or drainage. To protect from this form of infection, it is important to thoroughly dry the ears after exposing them to water with a towel. To protect the ears during exposure, the individual can use a head cap, ear plugs, or custom-fitted swim molds.<ref>{{Cite web|url=https://www.cdc.gov/healthywater/swimming/swimmers/rwi/ear-infections.html|title=Ear Infections {{!}} Healthy Swimming {{!}} Healthy Water {{!}} CDC|date=2017-06-19|website=www.cdc.gov|language=en-us|access-date=2018-03-09}}</ref>

A 2003 study published in ''Clinical Otolaryngology'' found that a cotton ball saturated with petroleum jelly was more effective at keeping water out of the ear, was easier to use, and was more comfortable than wax plugs, foam plugs, EarGuard, or Aquafit.<ref>{{cite journal |doi=10.1111/j.1365-2273.2004.00795.x |title=An objective evaluation of the waterproofing qualities, ease of insertion and comfort of commonly available earplugs |year=2004 |last1=Chisholm |first1=E.J. |last2=Kuchai |first2=R. |last3=McPartlin |first3=D. |journal=Clinical Otolaryngology and Allied Sciences |volume=29 |issue=2 |pages=128–32 |pmid=15113295}}</ref>

[[Jacques-Yves Cousteau]]<ref>''[[The Silent World: A Story of Undersea Discovery and Adventure|The Silent World]]'' (New York:1953, Harper, pp. 5-6)</ref> warned that earplugs are harmful to divers, especially [[Scuba diving|scuba divers]]. Scuba divers breathe compressed [[air]] or other gas mixtures at a pressure matching the water pressure. This pressure is also inside the ear, but not between the eardrum and the earplug, so the pressure behind the eardrum will often burst the eardrum. Skin divers have less pressure inside the ears, but they also have only atmospheric pressure in the outer ear canal. The PADI (Professional Association of Diving Instructors) advises in the "Open Water Diver Manual" that only vented earplugs designed for diving should be used in diving.

===Flight ear protection===
Earplugs are also available which help to protect ears from the pain caused by airplane cabin pressure changes. Some products contain a porous ceramic insert which reportedly aids equalization of air pressure between the middle and outer ear thereby preventing pain during landings and take-offs. Some airlines distribute regular foam earplugs as part of their amenity kits for passengers to aid their comfort during landings and takeoffs as well as to reduce exposure to the aircraft's noise during the flight. These can help passengers get to sleep during the flight if desired.