What is Consonance?

We all noticed at some point that some isolated sounds are disturbing us, but others are making us calm, or evoking pleasant feelings while listening to them. This mysterious phenomenon, where some sounds are causing pleasant feelings, is called Consonance. The "opposite" term Dissonance, is the one that is causing unpleasant (disturbing) feelings. It is as simple as that. For the purpose of this text, and as many experts agree, we will consider Dissonance simply as the opposite phenomenon to Consonance (although some scientists and musicians have different views).

Now, the answer to the question "why we do like some sounds, but dislike others" is not so clear, and for many centuries, scientists and musicians were trying to find what is causing Consonance. Some thought that the reason is in the mathematical ratios of the frequencies of the sounds, some looked for the causes in physics, and lately, some are probing biological and neural causes.

As you can assume, things can get very complicated when mixing all these fields of science together. In order to simplify the research in Consonance, the scientists and the musicians took the tones of the musical scale:

• American names of tones: C, C#, D, D#, E, F, F#, G, G#, A, A# B, C+

• European names of tones (1): C, C#, D, D#, E, F, F#, G, G#, A, A# H, C+

• European names of tones (2): Do, Do#, Re, Re#, Mi, Fa, Sol, Sol#, La, La#, Si, Do

Then they built all the possible two-tone combinations, keeping the tone C as the fixed first tone. When the two-tones of any of these combinations are played together (simultaneously), we hear a complex sound which musicians are calling a two-tone interval. So, they arranged these two-tone intervals in a list and gave them names that make sense to the musicians:

The scientists and the musicians ordered this two-tone interval list by the level of pleasantness that we experience while listening to them. Such ordered list is called the Consonance list (or the Consonance pattern).

Many listening experiments were performed where people were comparing the pleasantness of these intervals. After so many experiments, the scientists and the musicians have widely agreed that the order in the table above is the the one that best represents the order of pleasantness in the Western musical culture.

For those reasons, this Consonance list (or Consonance pattern) is used in the research of Consonance. The scientists suggested different explanations of the causes for Consonance, and built models in order to reproduce the Consonance list (pattern) - and recently they got very close in reproducing almost all of it - but not completely and not perfectly.

In our study, published in October 2017, we offered a hypothesis about the causes for Consonance, and built a model based on that hypothesis that reproduced, both, completely and perfectly the Consonance list (pattern), for the first time in history of pursuing the causes of this phenomenon.