What's the most dissonant interval?

[Bob]

(and why?) 

I found Hindemith's list.  I was wondering about ratios.

What say you?

More specifically I'm wondering if a m2 vs. tritone is more dissonant.

[ted]

It depends on context and the listener doesn't it Bob ?

[visitor]

Tonal system you're in matters too like Ted said, context, since w non western tonal basis you can have quarter tones, etc, Bartok tried to reconcile it as best as could be dome given our main systems limits.

[klavieronin]

If you define dissonance as the the interval most wanting to resolve then I would have to say the tritone because it kind of defines the V7-I cadence which, in the tonal system at least, is the 'strongest' cadence.

However, here is another take from Vincent Persichetti's Twentieth Century Harmony;

[xdjuicebox]

The harshest dissonance is probably the half-step - at least mathematically speaking. I find m9's to be a lot more dissonant than m2's though, especially it doesn't sandwich a tritone.

[ahinton]

Dissonance is  in the ear of the beholder and is also context dependent. For example, Richard Strauss, in Ein Heldenleben, writes the semitonal cluster D / E flat / F flat, scores it for oboes and cor anglé doubling three trombones and marks it sfz and then repeats this twice; it is underpinned by a diminshed seventh chord whose root is A. Similarly, Chopin writes a chord including a semitonal cluster E# / F# / G underpinned by an F# towards the end of his Scherzo No. 1 in B minor and marks it fff and then repeats it eight times (measures 594-599 inclusive); curiously, he does the same in his later Polonaise-Fantaisie three measures before the Più Lento section in B major (same notes as in the Scherzo example and also underpinned by an F#), although here the dynamic is pp and there are no reiterations.

These three examples are all "dissonances" in one sense and yet they are each in a specifically tonal context which might be argued to mollify their "dissonant" impact.

Best,

Alistair

[Bob]

Still reading.  But I was thinking it would sticking within chromatic notes, no quarter tones.  Initially I was thinking some with math that showed ratios.  Now I'm wondering if that would really do it though.

What other context things would affect dissonance?  Besides two notes?

[klavieronin]

One idea I have heard is that the most consonant intervals are the ones who's overtones series overlap the most. By the same token, the more disagreement between two overtone series the more dissonant and interval will be.

One issue with that is that the overtone series isn't perfectly reflected in the chromatic scale. If you were going to use it to find consonant/dissonant intervals you would have to allow yourself a little wiggle room.

[perfect_pitch]

I'd say a half minor 2nd (C and three-quarter tone D flat), or maybe a half diminished octave (C and one-quarter tone C flat)

That's just evil.

[visitor]

Still reading.  But I was thinking it would sticking within chromatic notes, no quarter tones.  Initially I was thinking some with math that showed ratios.  Now I'm wondering if that would really do it though.

What other context things would affect dissonance?  Besides two notes?

hmm, a low pedal tone that could fit into harmony for both dissonant notes would likely 'lessen' the dissonance we perceive.

[fftransform]

A tritone isn't an interval.  Who would think that C-D-E is more dissonant than pounding out a tone cluster with your fist?  Consonance and dissonance are intrinsic properties of an interval/chord.  Any mess of notes can be made to sound coherent with an otherwise-melodic piece, given repetition and voicing.

Here is a very coherent piece full of tone clusters.  It's still incredibly dissonant, regardless of the fact that the ugliness fits together neatly.  I feel like people are just shifting the goalposts (or making up wrong definitions of 'dissonance') on this question, when the answer is readily available.

If you are asking, "is there a chord that is going to sound nasty no matter what piece it's in the middle of, and no matter how it's voiced," then the answer is no.  Late Scriabin is your immediate counterexample.  Ives if that's not nasty enough.

[fftransform]

Re: tritones

[klavieronin]

A tritone isn't an interval.

A tritone isn't an interval? What is it then? And what about a diminished 5th or augmented 4th?

[fftransform]

A tritone isn't an interval? What is it then? And what about a diminished 5th or augmented 4th?

Sorry, my bad; sometimes a chord consisting of three whole steps (e.g. C-D-E) is called a tritone and from Alistair's comment I thought that was the context the word was being used in.

The most dissonant interval is just the m2.

[klavieronin]

I haven't heard that use of the term before. Interesting. I guess it's like a tertra chord but with three notes instead of four.

[toughbo]

Sorry, my bad; sometimes a chord consisting of three whole steps (e.g. C-D-E) is called a tritone and from Alistair's comment I thought that was the context the word was being used in.

The most dissonant interval is just the m2.

Sure you don't mean triad?

To me m2 sounds less dissonant than m9

[timothy42b]

How about a mistuned unison on piano?

Or on other instruments where intonation is a problem, slightly mistuned unisons? 

Slight variations in tuning may cause any given interval to be more dissonant.  Even a major chord, if held steady in good acoustics and played in ET, will sound like it wants to resolve.  Instruments that can adjust pitch, like fretless strings, will intuitively make small adjustments.  Lower the third 13 cents, raise the fifth 2 cents, and the chord sounds different. 

[keypeg]

Just saw this.

Sorry, my bad; sometimes a chord consisting of three whole steps (e.g. C-D-E) is called a tritone and from Alistair's comment I thought that was the context the word was being used in.

I've always seen this called an augmented chord.  That's interesting because you do indeed have perpetual tritones.  Is it in "non-classical" that it's called tritone chord?

[Bob]

I was sticking a standard chromatic scale.

It would have to be something like
A4/d5
m2
M7

Although there has to be some difference to an extra octave....
m9
A11/d12
M14


I was thinking a diad also.... I wonder if the rest, it must, would affect it.  A M7 chord would be softened for dissonance compared to a M7 diad.

[timothy42b]

Long ago a pastor requested a favorite hymn for his last service at that church.

The tune name was Ton-y-botel. 

Oh, I see it's also called Ebenezer.

That's not me playing, by the way. 

Anyway, it took a huge amount of practice to get it under my fingers (low skill level at the time.  Worse now!)  I came to intensely dislike it.  It just sounded dissonant all the way on my digital piano.

But in church I played it on organ and the dissonances weren't there.  My theory is the intonation of the organ was different enough to be effectively a different temperament.