Binaural recording is a method of recording sound that uses two microphones, arranged with the intent to create a 3-D stereo sound sensation for the listener of actually being in the room with the performers or instruments. This effect is often created using a technique known as dummy head recording, wherein a mannequin head is fitted with a microphone in each ear. Binaural recording is intended for replay using headphones and will not translate properly over stereo speakers. This idea of a three-dimensional or "internal" form of sound has also translated into useful advancement of technology in many things such as stethoscopes creating "in-head" acoustics and IMAX movies being able to create a three-dimensional acoustic experience.
Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound. Headphones let a single user listen to an audio source privately, in contrast to a loudspeaker, which emits sound into the open air for anyone nearby to hear. Headphones are also known as earphones or, colloquially, cans. Circumaural and supra-aural headphones use a band over the top of the head to hold the speakers in place. Another type, known as earbuds or earpieces consist of individual units that plug into the user's ear canal. A third type are bone conduction headphones, which typically wrap around the back of the head and rest in front of the ear canal, leaving the ear canal open. In the context of telecommunication, a headset is a combination of headphone and microphone.
Sound quality is typically an assessment of the accuracy, fidelity, or intelligibility of audio output from an electronic device. Quality can be measured objectively, such as when tools are used to gauge the accuracy with which the device reproduces an original sound; or it can be measured subjectively, such as when human listeners respond to the sound or gauge its perceived similarity to another sound.
A hearing aid is a device designed to improve hearing by making sound audible to a person with hearing loss. Hearing aids are classified as medical devices in most countries, and regulated by the respective regulations. Small audio amplifiers such as personal sound amplification products (PSAPs) or other plain sound reinforcing systems cannot be sold as "hearing aids".
Unilateral hearing loss (UHL) is a type of hearing impairment where there is normal hearing in one ear and impaired hearing in the other ear.
The carbon microphone, also known as carbon button microphone, button microphone, or carbon transmitter, is a type of microphone, a transducer that converts sound to an electrical audio signal. It consists of two metal plates separated by granules of carbon. One plate is very thin and faces toward the speaking person, acting as a diaphragm. Sound waves striking the diaphragm cause it to vibrate, exerting a varying pressure on the granules, which in turn changes the electrical resistance between the plates. Higher pressure lowers the resistance as the granules are pushed closer together. A steady direct current is passed between the plates through the granules. The varying resistance results in a modulation of the current, creating a varying electric current that reproduces the varying pressure of the sound wave. In telephony, this undulating current is directly passed through the telephone wires to the central office. In public address systems it is amplified by an audio amplifier. The frequency response of most carbon microphones, however, is limited to a narrow range, and the device produces significant electrical noise.
Adaptive feedback cancellation is a common method of cancelling audio feedback in a variety of electro-acoustic systems such as digital hearing aids. The time varying acoustic feedback leakage paths can only be eliminated with adaptive feedback cancellation. When an electro-acoustic system with an adaptive feedback canceller is presented with a correlated input signal, a recurrent distortion artifact, entrainment is generated. There is a difference between the system identification and feedback cancellation.
A contralateral routing of signals (CROS) hearing aid is a type of hearing aid that is used to treat a condition in which the patient has no usable hearing in one ear and minimal hearing loss or normal hearing in the other ear. This is referred to as single sided deafness.
In-ear monitors, or simply IEMs or in-ears, are devices used by musicians, audio engineers and audiophiles to listen to music or to hear a personal mix of vocals and stage instrumentation for live performance or recording studio mixing. They are also used by television presenters to receive vocal instructions, information and breaking news announcements from a producer that only the presenter hears. They are often custom-fitted to an individual's ears to provide comfort and a high level of noise reduction from ambient surroundings. Their origins as a tool in live music performance can be traced back to the mid-1980s.
In audiology, the Articulation Index (AI) is a tool used to predict the amount of speech that is audible to a patient with a specific hearing loss. The AI figure for a given patient can range from zero to one, representing the proportion of the average speech signal that is audible. The closer the AI is to one, or 100 percent, the better the person should be able to hear speech. The calculation is also used in industrial settings for the design of safety devices, such as flight helmets, where audio signals are required to be clearly heard.
Adaptive equipment are devices that are used to assist bathing, dressing, grooming, toileting, and feeding are self-care activities that are including in the spectrum of activities of daily living (ADLs). Jennifer McLaughlin Maly a P.T./ D.P.T. in her article located in the journal Exceptional Parent gives a more complete definition of adaptive equipment:
"Typically, a piece of adaptive equipment is utilized to increase a child's function. Examples of adaptive equipment or assistive technology are wheelchairs, lifts, standing frames, gait trainers, augmentative communication devices, bath chairs, and recreational items such as swings or tricycles."
Electric acoustic stimulation (EAS) is the use of a hearing aid and a cochlear implant technology together in the same ear. EAS is intended for people with high-frequency hearing loss, who can hear low-pitched sounds but not high-pitched ones. The hearing aid acoustically amplifies low-frequency sounds, while the cochlear implant electrically stimulates the middle- and high-frequency sounds. The inner ear then processes the acoustic and electric stimuli simultaneously, to give the patient the perception of sound.
Audio induction loop systems, also called audio-frequency induction loops (AFILs) or hearing loops, are an assistive listening technology for individuals with reduced ranges of hearing.
Miracle-Ear, Inc. is a hearing aid and hearing care company consisting of a network of franchised and corporately-owned retail locations. The company is a subsidiary of Amplifon, the worldwide leader in hearing care and hearing aid retail based in Milan, Italy. Miracle-Ear's U.S. headquarters are located in Minneapolis, Minnesota. As of 2023 it has more than 1,500 locations in the United States, and it is the best-known hearing aid brand in the U.S.
The first hearing aid was created in the 17th century. The movement toward modern hearing aids began with the creation of the telephone, and the first electric hearing aid was created in 1898. By the late 20th century, the digital hearing aid was distributed to the public commercially. Some of the first hearing aids were external hearing aids. External hearing aids direct sounds in front of the ear and block all other noises. The apparatus would fit behind or in the ear.
SoundBite Hearing System is a non-surgical bone conduction prosthetic device that transmits sound via the teeth. It is an alternative to surgical bone conduction prosthetic devices, which require surgical implantation into the skull to conduct sound.
Personal Sound Amplification Products, also known as "Personal Sound Amplification Devices," or by the acronym PSAP, are defined by the U.S. Food and Drug Administration as wearable electronic products that are intended to amplify sounds for people who are not Deaf or Hard of Hearing. They are not hearing aids, which the FDA describes as intended to compensate for hearing loss. According to Dr. Mann of the FDA, choosing a PSAP as a substitute for a hearing aid can lead to more damage to your hearing.
Assistive Technology for the Deaf and Hard of Hearing is technology built to assist those who are deaf or suffer from hearing loss. Examples of such technology include hearing aids, video relay services, tactile devices, alerting devices and technology for supporting communication.
TV Ears is an American, privately held audio technology company that specializes in voice clarifying television products for the hearing impaired. It was founded in April 1998 by George Dennis. They are located in Spring Valley, California, where they house the North American distribution center, support, and sales teams, while employing approximately 50 people. TV Ears serves hearing impaired customers throughout the world, with their predominant markets being in the United States, Canada, and Europe.
Treatment depends on the specific cause if known as well as the extent, type, and configuration of the hearing loss. Most hearing loss results from age and noise, is progressive, and irreversible. There are currently no approved or recommended treatments to restore hearing; it is commonly managed through using hearing aids. A few specific types of hearing loss are amenable to surgical treatment. In other cases, treatment involves addressing underlying pathologies, but any hearing loss incurred may be permanent.
