EQ controls: Equalization, more commonly referred to as EQ, controls the different aspects of sound that come through your headphones, and some headphones come with custom apps that let you adjust the EQ in granular detail. With the right EQ controls, you can add more treble, bump up the bass, or just create a sound profile that’s suited to your tastes. If you’re into customizing how your music sounds, look for headphones that work with an EQ app.
Hearing risk from headphones' use also applies to workers who must wear electronic or communication headsets as part of their daily job (i.e., pilots, call center and dispatch operators, sound engineers, firefighters, etc.) and hearing damage depends on the exposure time. The National Institute for Occupational Safety and Health (NIOSH) recommends sound exposure not exceed 85 dB(A) over 8 hour work day as a time-weighted average. NIOSH uses the 3-dB exchange rate often referred to as "time-intensity tradeoff" which means if sound exposure level is increased by 3 decibels, the duration of exposure should be cut in half. NIOSH published several documents targeted at protecting the hearing of workers who must wear communication headsets such as call center operators, firefighters, and musicians and sound engineers.
Alternatively, online calculators can be used. Once the sensitivity per volt is known, the maximum volume for a pair of headphones can be easily calculated from the maximum amplifier output voltage. For example, for a headphone with a sensitivity of 100 dB (SPL)/V, an amplifier with an output of 1 root mean square (RMS) voltage produces a maximum volume of 100 dB.
Smaller earbud type earpieces, which plugged into the user's ear canal, were first developed for hearing aids. They became widely used with transistor radios, which commercially appeared in 1954 with the introduction of the Regency TR-1. The most popular audio device in history, the transistor radio changed listening habits, allowing people to listen to radio anywhere. The earbud uses either a moving iron driver or a piezoelectric crystal to produce sound. The 3.5 mm radio and phone connector, which is the most commonly used in portable application today, has been used at least since the Sony EFM-117J transistor radio, which was released in 1964. Its popularity was reinforced with its use on the Walkman portable tape player in 1979.
Whether you wear headphones for your daily commute, regular workouts, or just for jamming out at home, you need a good pair that’s comfortable and can make everything sound great. Headphone tech has evolved significantly, too, so some pairs can do a lot more than just play sound. It’s not tough to find a pair that can connect to your smartphone wirelessly, or one that can keep outside commotion out.