Two tones close together and simultaneously sounding are not always perceived as two individual tones or a musical interval. They can also have a completely different effect depending on how they are tuned.

Give it a try! Use the slider to detune two tones from each other gradually. Do you now perceive a pulsation of the sound that gets louder and softer, the so-called beat? The beat becomes faster with increasing distance until it is no longer audible. Now an eclectic sound can be perceived, which is called rough. The degree to which the roughness is perceived can be calculated from the pitch distance and is shown in the graphic.

Now, increase the distance even further! Can you recognize the two individual tones? They can be heard best if you move the slider ultimately to the right or left. Here you can listen to the interval of a major third.