What are Mono Headphones?
Mono Headphones (also called monaural headphones) are headphones which can only play sound from a single channel. This is in contrast to stereo headphones, which can play back sound from two separate independent channels, a left channel and a right channel.
As stated, mono headphones can only play back sound from a single channel. Many times, recordings are made on two channels; this is called stereo recording. Stereo recordings consist of a left input recording and a right input recording. The other type of recording is mono recording, which is recording that is done on just one channel; no separate left and right channels. Mono headphones can play back the exact sound from a mono recording, since it plays back sound from only a single channel. However, if playing back sound from a stereo recording, it can only play back one channel, usually the left channel. Thus, the right channel is ignored and cannot be heard. So it's as if a user gets back only half the recording when playing a stereo recording on mono headphones. For this reason, it is recommended to only use mono headphones for mono recordings. Stereo headphones, though, can be played on both mono and stereo recordings.
Uses of Mono Headphones
Mono headphones are not used as much on the market as stereo headphones anymore because audio has now largely turned in the way of stereo recordings. Being that stereo can produce directional sound, sound appearing to come from left and right, it produces a dynamic surround effect that mono recording cannot reproduce. For most applications, including music, sounds from movies, to play back the sound as they are recorded, stereo headphones must be used. However, mono headphones still have applications, which is why they are still sold and largely available.
Even with stereo's dominance, there are still many applications where mono recordings or devices are used. Hospital televisions and radios are both mono devices, since many times patients are deaf in one ear. Thus, mono headphones work perfectly with these devices, since they output sound only onto one channel. Another mono device is tape recorders. Tape recorders record in mono. So when listening to tape recordings, a mono headphone lends itself perfectly to this. Another type of communication that is mono is telephone communication. So if listening on the telephone on a computer with an application such as skype, a mono headset can be used. Thus, mono headphones and headsets still have great application and use today.