Do you know the Headphones Applications?

Headphones can be used with stationary CD and DVD players, home theater systems, personal computers, or portable devices (such as digital audio players, MP3 players, and mobile phones) that have a headphone jack. Cordless headphones do not use a cable to connect to their source. They instead receive a radio or infrared signal that has been encoded via a radio or infrared transmission link, such as FM, Bluetooth, or Wi-Fi. The headphones are simply a component of these battery-powered receiver systems. Cordless headphones are utilized at silent discos and silent gigs.

Headphones are used in live scenarios by disc jockeys with a DJ mixer and sound engineers to monitor signal sources in the professional audio industry. DJs in radio studios wear headphones while speaking into the microphone, with the speakers turned off, to eliminate acoustic feedback while monitoring their voice. Musicians and singers use headphones in studio recordings to play or sing along to a backing track or band. Audio signals of various types are monitored using headphones in military applications.

A cable connects wired headphones to an audio source. 6.35 mm (1/4 inch) and 3.5 mm phone connectors are the most common. On fixed-location homes or professional equipment, the larger 6.35 mm connector is more common. Today, the 3.5 mm connector is the most commonly used connector for portable applications. There are adapters available to convert between 6.35 mm and 3.5 mm devices.

As an active component, wireless headphones tend to be costlier due to the necessity for internal hardware such as a battery, a charging controller, a speaker driver, and a wireless transceiver, whereas wired headphones are a passive component, outsourcing speaker driving to the audio source.

Some headphone cords are equipped with a serial potentiometer for volume control.

Wired headphones may be equipped with a non-detachable cable or a detachable auxiliary male-to-male plug, as well as some with two ports to allow connecting another wired headphone in a parallel circuit, which splits the audio signal to share with another participant, but can also be used to hear audio from two inputs simultaneously. An external audio splitter can retrofit this ability.

Applications for audiometric testing

Various types of specially designed headphones or earphones are also used to evaluate the status of the auditory system in the field of audiology for establishing hearing thresholds, medically diagnosing hearing loss, identifying another hearing-related disease, and monitoring hearing status in occupational hearing conservation programs. Specific models of headphones have been adopted as the standard due to the ease of calibration and ability to compare results between testing facilities.

Supra-aural style headphones have historically been the most commonly used in audiology as they are the easiest to calibrate and have long been considered the standard. The Telephonics Dynamic Headphone (TDH) 39, TDH-49, and TDH-50 are popular models. In-the-ear or insert-style earphones are becoming more popular because they provide higher levels of interaural attenuation, introduce less variability when testing frequencies between 6,000 and 8,000 Hz, and avoid testing issues caused by collapsed ear canals. The Etymotic Research ER-3A is a popular model of insert earphones. Circum-aural earphones are also used to determine hearing thresholds in the high-frequency range (8,000 Hz to 20,000 kHz). The Sennheiser HDA300 and Koss HV/1A circum-aural earphones, along with the Etymotic Research ER-2A insert earphones, are the only models that have reference equivalent threshold sound pressure level values for the extended high-frequency range as described by ANSI standards.

Audiometers and headphones must be calibrated at the same time. The output signal from the audiometer to the headphones is measured with a sound level meter during the calibration process to ensure that the signal is accurate to the audiometer reading for sound pressure level and frequency. The earphones are calibrated in an acoustic coupler designed to mimic the transfer function of the outer ear. Because specific headphones are used in the initial audiometer calibration process, they cannot be replaced with any other set of headphones, even from the same make and model.