Alternatively, online calculators can be used.[13] 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.
The outer shells of in-ear headphones are made up of a variety of materials, such as plastic, aluminum, ceramic and other metal alloys. Because in-ear headphones engage the ear canal, they can be prone to sliding out, and they block out much environmental noise. Lack of sound from the environment can be a problem when sound is a necessary cue for safety or other reasons, as when walking, driving, or riding near or in vehicular traffic.[19]
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.
Earbuds have small speakers that rest on the ear canal of the wearer. These are usually much less expensive than on-ear and over-ear headphones and reproduce the sound well. However, outside sounds, such as traffic or power tools, can get past the earbuds and interfere with your enjoyment. Earbuds also don't stay in place very well if the wearer is moving much, such as exercising. These also are lower fidelity than on-ear and over-ear headphones.