Daniel Penalva wrote: ↑
Mon Jul 24, 2017 3:15 pm
What make a dissonance in a chord ?
That question is different from "What is dissonance in music ?", since its more punctual.
More specific, maybe. The standard explanation of dissonance is that it is caused by beating between two frequencies. If you search for just intonation lissajous on YT you will find an explanation of beating and some demonstrations.
I have been reading some texts books that says some intervals are dissonant, and that dissonance goes on intervals up to 13th (the 6th from the next octave). So why is that dissonance goes until 13th but not 14th ? Why 10th(octave above 3th) is dissonant but 12th(octave above 5th) not Why some intervals render a chord dissonant and others not ?
I don't really understand this. I wouldn't call a 10th dissonant but I think you have to let the ear judge how much the notes clash. I wouldn't say that they do in the case of a 10th or a perfect 12th, although the 10th has more personality. A diminished 12th definitely clashes. This is more or less in line with how much the intervals in question beat, which is what makes the beating theory plausible. The trouble is that a diminished 12th in a low register beats less than (say) a minor third in a high register, but is more dissonant, so beating can't be the whole story.
There must be a answer that is partially physical-aesthetical(must resolve tension thing and maybe other matters).
Up to you to come up with it, then. The physical answer isn't very convincing. I think that it is important to distinguish between auditory phenomena and musical phenomena, and that any theory which fails to draw this distinction is unlikely to get very far. Beating is an auditory phenomenon so I am not surprised to find that dissonance, which is a musical phenomenon, is related but not the same. Perhaps what I mean by musical rather than auditory is the same as what you mean by physical-aesthetic.
The 'must resolve' thing is interesting because not all dissonance produces a need to resolve, at least not in all contexts. Some dissonance adds colour while some adds impetus. This is obviously important in music but is not very well explained.