A night out at the karaoke bar will likely confirm most of the suspicions you had about each of your co-workers. Yet, there may be one unexpected surprise: In addition to not being able to hit the high notes in a song, one of your other co-workers can't hit any notes at all.
As you watch your co-worker murder several songs over the course of the evening, but this guy, enthusiastically singing his heart out has absolutely no idea how bad he is. This might be due to his growing bar tab or this guy might be tone deaf.
Tone deafness, also called amusia, has nothing whatsoever to do with actual deafness, so while your co-worker can't hear how bad he is, he can hear you talk about how bad he is.
The tone-deaf also have perfect hearing when it comes to music. However, what they perceive when they hear music is the sound of a perfect mess. Some tone-deaf people describe listening to music as something similar to listening to pots and pans clanging about. While the rest of us may flinch when a tone-deaf person grabs the microphone, the tone deaf can't enjoy anyone else's singing at all. In that sense, karaoke night for the tone deaf is marked by a perfect reproduction of what music sounds like to them.
So what's going on?
Perceiving Pitch: When you don't know which note is which
So, what is it that a tone-deaf person doesn’t perceive correctly? The answer is pitch. Pitch is the highness or lowness of a sound. If you were to play the first key on a piano keyboard, you would hear a low note, or low pitch. Playing the last key on the keyboard would produce a high note, or high pitch. The keys are attached to firm strings of different lengths inside the piano. When these strings are plucked, they vibrate. A vibration extends the entire length of a string. So an amount of force exerted on a longer string will result in a slower vibration (lower note), and that same force on a shorter string will produce a faster vibration (higher note). This vibration transfers to the air around it, ultimately reaching your ears, which begins the brain's processing of a sound.
Most people can tell the difference between high and low notes. Tone-deaf people, however, can't differentiate between two different notes.
A person with poor pitch perception may be able to improve his or her ability to differentiate pitches or mimic them, but a person who is truly tone deaf may not have the capacity to improve whatsoever no matter how much he or she practices. It's not the reception of the tone that is compromised, but the brain's processing of it.
So if you tell a tone-deaf person “nice singing” after they've left the karaoke stage, don't do it too starkily. Tone-deaf people can detect sarcasm and other tonal variations in the human voice either.