Combination tone

Combination tones are special sounds that we can hear when we listen to certain kinds of noises. Imagine that you have two different sounds playing at the same time – we can call them Sound A and Sound B. When we hear them together, our ears might pick up a new sound that we didn't hear before, which is called a combination tone.

These combination tones are created by the way our ears perceive different types of sound waves. Some of the waves from Sound A and Sound B can interfere with each other in a special way that produces a third sound – the combination tone.

There are two kinds of combination tones that we often hear: sum tones and difference tones. A sum tone happens when the waves from Sound A and Sound B add together to create a new sound that is higher in pitch than either of the original sounds. A difference tone happens when the waves from Sound A and Sound B interact in a different way that creates a new sound that is lower in pitch than either of the original sounds.

One example of combination tones that you might have heard of is the "beat" that you can hear when two tuning forks are played together. When tuning forks are played together, they create a small difference in frequency, which causes the combination tone to be produced – this is what we hear as the beat.

So, in summary, combination tones are special sounds that are created by the interaction of different types of sound waves. They can be either sum tones, which are higher in pitch than the original sounds, or difference tones, which are lower in pitch.