What Music Really İs


Bo C-sen's    1st   online course

Learn to Hear the Dissonances
of Equal Temperament

Hi, I call myself Bo Constantinsen and I am excited to share with you a great insight which will help you open your ears and experience personally some of the acoustical facts at the base of consonance and dissonance.


Perhaps a better name for this course would have been “Learn to Hear the Mistunings of Equal Temperament” because, as stated in the course, the notions of consonance and dissonance have a long history of controversy. This delicate subject is still debated by musicians, and the goal of the present course is not to give arguments in favour of one theory, but rather to expose an approach of differentiating between alternatively tuned variants of tones, which in cultural music have the same name and function.

Learn to Hear the Dissonances of Equal Temperament — course poster (fingernails on blackboard scratching musical notes)

The option of having a word like “mistunings” in the title might lead some to think that this course could be focusing on learning how to hear whether a piano, for example, is properly tuned or not. Tuning a piano is an art in itself, and the prevalent tuning system known as “12-tone equal temperament”, has been, and is still being heard almost exclusively everywhere in the west, while being adopted all over the world. People say there is good music and bad music written and performed in 12-tone equal temperament, but the acoustical facts at the base of this tuning-compromise are independent of subjective musical taste.

Indeed, the title “dissonances of equal temperament” might disturb some musicians, so I’d like to clarify that the intention of this endeavour is to bring an homage to our culture and our music, by understanding it better.


This course in not about what equal temperament is and how it became the standard tuning in the west. It’s not about how to properly tune musical instruments; it is not about the tuning battle between just intonation and equal temperament, nor is it about the number of Hertz in standard concert pitch (i.e. “440 vs 432”).

Rather, this course empowers students with the knowledge and tools needed to listen, hear, discern and recognize both consonance and dissonance, in terms of mistunings — by listening alone. The experience of actually hearing and the insights which come with it will help answer musical questions and form unbiased personal opinions.

Learn to Hear the Dissonances of Equal Temperament — course poster (fingernails on blackboard scratching musical notes)

This presentation does not make use of any standardized music theory or nomenclature. Acoustic phenomena are discussed and analysed in their raw form, and visualized exactly as they are perceived through the sense of hearing. It was my intention to put together the information for this course by omitting circular references, since I believe in the purpose of understanding a point of view that doesn't limit theory to one system alone.

Innocent music lovers will find this approach enlightening and, even though the course is primarily aimed at beginners, it is my hope that educated musicians will open heartedly appreciate this information which is not to be found in any scholar curriculum in its entirety.

At the end of each lesson cross-references will be given to symbols used in established musical practices, to give those acquainted with them the opportunity to connect the information presented here with their body of knowledge.