Originally Posted by: hsnoeckx

A tritone is not the most dissonant sound there is; an augmented fourth ( or likewise a diminished fifth ) is the most dissonant and in the dark centuries it was seen as the Devil's interval and was absolutely forbidden by the church to use in music.

An augmented fourth would be like C to F# ( or Gb ).

Herman

That isn't quite right, but here is a good page about Consonance and Dissonance:

https://en.wikipedia.org/wiki/Consonance_and_dissonance

And one about Tritones / Augmented 4th / Diminished 5th:

https://en.wikipedia.org/wiki/Tritone

-Carl.