interval quality question

[shugs]

I do understand that but not seeing the bearing on consonance and dissonance.

[vurt]

I do understand that but not seeing the bearing on consonance and dissonance.

things that sound unpleasant in one key, may sound pleasant in another.
in relation to the tonic.

[cryophonik]

I don't need to beat a dead horse. I guess everyone agrees C to F flat is dissonant, not because of how it sounds, but because all diminished fourths are defined to be dissonant and it is as simple as that

These intervals need to be viewed/heard in the context of the music to understand whether they're consonant (e.g., major third) or dissonant (e.g., diminished fourth). "Diminished fourth" is simply the nomenclature used for a specific interval and it implies a context (e.g., key, or the underlying chords). C-E in the key of C is considered consonant because it is the root and third of the tonic chord (or perhaps the third and fifth of the vi-chord). The C-F♭ interval does not occur naturally in the key of C Major (nor do any diminished fourth intervals), and implies that it is part of another non-harmonic chord (e.g., third inversion of a D♭m add M7).

[Hink]

I don't need to beat a dead horse. I guess everyone agrees C to F flat is dissonant, not because of how it sounds, but because all diminished fourths are defined to be dissonant and it is as simple as that

but that's not correct, C>E is Major third...you realize that Fb sounds as the same note as E, C>E is a major 3rd the spelling is different, the notes are the same because it is not written the same...this where you ears come in. Every single time will be different, where you are going, what you are trying to express, like bert said dissonance creates tension...this is not something y6ou tell someone, it is something one feels and as such the decisions should be based on the piece, not some rule you want to create

[Hink]

I do understand that but not seeing the bearing on consonance and dissonance.

actually I think you are way overthinking it...do you play an instrument? (that is not meant in the negative, just different experiences)

[shugs]

played Clarinet when younger for about 5 years until about age 14 and picked up a guitar about a year ago, off and on....probably a novice at best. ...You are probably right about over thinking it. If I sit you on a couch and play C and F flat simultaneously and nothing else, you will probably say that sounds consonant. Maybe if I start playing more of the song, you will say " ooh that doesn't sound quite right and needs resolved; it is very dissonant" So I guess my (dumb) point is, the definition that I have been given of dissonance is lacking ( maybe)

[cryophonik]

So I guess my (dumb) point is, the definition that I have been given of dissonance is lacking ( maybe)

It’s lacking context. A major third would not occur in the same context that a diminished fourth would. Your ears are used to hearing what a major third sounds like, so when you play a diminished fourth in isolation, you hear a consonant major third. You need to hear the diminished fourth in context to hear it as dissonant.

[shugs]

yeah, I was thinking it had something to do with the actual frequency and amplitude of the sound waves, and how the two notes mesh together

[cryophonik]

No, it's simpler than that. Here's an easy exercise using my previous example:

Play C-E-G (C major triad). It has a major third and sounds consonant.

Play C F♭ A♭ D♭ (D♭m w/M7 third inversion) - it has a diminished fourth and sounds dissonant.

Diminished fourths/augmented fifths are not very common in most popular music (maybe in jazz, but my jazz theory knowledge is about 30 yrs old), probably because, unlike tritones, they don't occur naturally in any major or minor keys, so they're usually only found in chord extensions or maybe accidentals (e.g., passing notes) in certain situations.

[Hink]

I had a situation where I was working on a piece on my guitar and there is a long segment of just a two chord vamp on the synth in the background with a guitar solo on top of it. It started on D and then went down to the C, I wanted to call it Dm blindly simply because that is where it started but it wasnt and as I was working out a solo I found myself following my ear to a note that was not in the Dm scale (no biggie, I wasnt changing it, it was fun to play and that is far from uncommon). I was assuming that the D was my tonic, then I realized that D was not the tonic, it was the 5th and C was the 4th...still the same notes, still played it the same way but with a little more understanding.

Was it wrong, I am sure someone will tell me it was...but it was right for me, I love playing the piece...

[jancivil]

there is no wide consensus definition of dissonance. 'major third, so it's dissonant' was a kind of truism 700 yrs ago or something, but in general for centuries it's shown to be a... highly desirable harmony.

You'll get an academic kind of thing telling you a major seventh is dissonant; yet in particular contexts, that are not at all rare, it's a very pleasing, pretty final color to your I harmony. (Zappa once described qualities of harmonies in layman's terms to some journo - 'major 7th means you're in love'.)

So any definition of that kind of thing is entirely context-bound and subjective. It's seasoning, it's taste, do you like this at this juncture in time in your music, does it work? Is _all_ we have to worry about.

[jancivil]

that minor/major in 3rd inversion is a very good example of a real meaning in music.
a minor/major chord like that (m triad M7) is probably "dissonant", but what does it do? I love that thing, in itself tbh.

no real reason for diminished fourth to happen more frequently in jazz... and it may get spelled as M3 anyway to facilitate sight-reading.

[jancivil]

I don't need to beat a dead horse. I guess everyone agrees C to F flat is dissonant, not because of how it sounds, but because all diminished fourths are defined to be dissonant and it is as simple as that

By whom? Based in what? In itself, there is no difference from the major third. Don't believe everything you read or hear. Don't guess everyone agrees, it's a misconstruction. Even in the minor/major 3rd inversion the interval itself is not considered as different because of a spelling. That takes names of things over the thing itself.

C Fb Ab Db: the dissonance is the minor 9th C-Db; they were responding to you saying you keep on with the major third in isolation it's perceived as dissonant, only to provide a case subjectively/contextually where it would be perceived *differently* than a major third's part *in a major triad*.

[cryophonik]

I use major 7ths all the time and agree that they are very nice sounding, especially when used on the I and IV chords.

[cryophonik]

I don't need to beat a dead horse. I guess everyone agrees C to F flat is dissonant, not because of how it sounds, but because all diminished fourths are defined to be dissonant and it is as simple as that

By whom? Why? Based in what? In itself, there is no difference from the major third. Don't believe everything you read or hear. Don't guess everyone agrees, it's a misconstruction.

I think what he's saying is that, if you look at textbook definitions, they will call a diminished fourth or augmented fifth a "dissonant" interval (I've certainly seen it myself many times). But, I agree that, without any musical context, there's nothing dissonant about their sound.