# Usefullness of terms like tonic and dominant?



## henrikhank

Hi!
I understand the practical use of roman numerals in harmonic analysis. What I do not understand is the practical use of the system using terms like tonic a dominant. Roman numerals helps you see how a song is harmonically constructed and makes transposing easier. I cannot see how the other system can help with that. Why then do we study this system and what are the correct terms for these two systems?


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## Nate Miller

musicians have to have language to communicate musical ideas. they really are not two systems, but rather two sets of terms for the same system, which is the system of functional harmony.

I believe the terms "dominant" and "tonic" predate Roman numeral analysis. Functional harmony didn't begin until JJ Ramaeu published his Treatise in 1722, the same year Bach published the WTC

which is why there are two sets of terms.

myself, I prefer you say tonic and dominant because there's less chance of my not hearing you properly, but the two sets of terms are freely interchangeable


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## Nate Miller

There's something else in the terms "tonic" and "dominant".

They can also refer to keys. In a modulation, you're talking about going to the "key of the dominant" in a section and things like that. 

so "tonic" and "dominant" can take on a wider meaning than just describing an individual chord. 

but the simple answer is what my old teacher used to say to me... "because music is hard and tricky"


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## EdwardBast

Roman numerals designate specific triads whereas tonic, subdominant and dominant designate functions. The IV chord in C major is F-A-C, whereas other triads and seventh chords, like D-F-A and D-F-A-C, for example, can perform a subdominant function. And as Nate suggests, when one says the exposition of a movement in sonata form modulates to the dominant, one means a key embodying a state of tension with respect to the tonic key analogous to that the dominant triad holds with respect to the tonic triad.


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## donald

I agree that the terms dominant and tonic have functional conotations that are lacking in the Roman numeral description. The linear musical scale can be re-written as a circle of fifths as in vii, iii, vi, ii, V, I, IV, and this is a canonical form of root motion in many pieces of music. Of those seven scale degrees or root chord tones, the V does dominate the harmony in many ways. If you look at many pieces by Mozart, Back Beethoven and many others, the chord that gets the most time and the most emphasis is the Dominant, whether in the home key or in a key that has been modulated to. The dominant chord is usually accented in relation to its resolution to the Tonic harmony as well. In fact, when it is not emphasized properly it can sound unmusical.
Just one other comment about the dominant chord is just how many altered notes it can handle. The augmented dominant seventh chord with added flat ninth and thirteenth comes to mind. Now that's a dominant chord.


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## Vox Gabrieli

+1

When you get more advanced in music theory, you'll be thankful to have learned terms like "tonic, supertonic, submediant, etc ". 
For example, you could tell somebody, "trumpets and timpani in the key of a minor, 1st and 3rd beats of the 1st measure, tonic and dominant", and I could be easily written out with no hassle. An inefficient way of doing this is " trumpets and timpani, 1st and 3rd beats, the first cord is from bottom to top: A, C, and E, the second chord is E, G, B. " See what I mean?


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## MadMusicist

Terms like "tonic" and "dominant" are used for much more than simply "spelling out" the notes of chords. Rather, they are used to indicate the function or the "parts of speech" of a particular musical aspect (chord, key, etc). To illustrate, the word "tonic" carries along with it a bunch of functional connotations, such as stability, relative centrality, resolution, the end of a perfect cadence, etc.


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## millionrainbows

henrikhank said:


> Hi!
> I understand the practical use of roman numerals in harmonic analysis. What I do not understand is the practical use of the system using terms like tonic a dominant. Roman numerals helps you see how a song is harmonically constructed and makes transposing easier. I cannot see how the other system can help with that. Why then do we study this system and what are the correct terms for these two systems?


The roman numerals, which indicate scale steps, are also ranked in terms of importance, meaning their relative consonance or dissonance in relation to I, or in other words, the tendency to want to resolve to I, or the "gravity" of the step.

These are ranked in order of importance. This is based on intervallic relations of the scale steps to the tonic note.

1. minor seventh (C-Bb) 9:16
2. major seventh (C-B) 8:15
3. major second (C-D) 8:9
4. minor sixth (C-Ab) 5:8
5. minor third (C-Eb) 5:6
6. major third (C-E) 4:5
7. major sixth (C-A) 3:5
8. perfect fourth (C-F) 3:4
9. perfect fifth (C-G) 2:3
10. octave (C-C') 1:2
11. unison (C-C) 1:1

So a C major scale's horizontal functions correspond to these harmonic relations; and one can observe how these functions were derived:

I - 1:1
ii - 8:9
iii - 4:5
IV - 3:4
V - 2:3
vi - 3:5
vii - 8:15

Their importance in establishing the tonalityis be ranked by the order of consonance to dissonance, with smaller-number ratios being more consonant.

I - 1:1 (tonic)
V - 2:3 (dominant)
IV - 3:4 (subdominant, etc.)
vi - 3:5
iii - 4:5
ii - 8:9
vii - 8:15


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## lifetweet

That's very much useful millionrainbows. That would make henrikhank enlightened and so do I. :tiphat:


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## tdc

millionrainbows said:


> The roman numerals, which indicate scale steps, are also ranked in terms of importance, meaning their relative consonance or dissonance in relation to I, or in other words, the tendency to want to resolve to I, or the "gravity" of the step.
> 
> These are ranked in order of importance. This is based on intervallic relations of the scale steps to the tonic note.
> 
> 1. minor seventh (C-Bb) 9:16
> 2. major seventh (C-B) 8:15
> 3. major second (C-D) 8:9
> 4. minor sixth (C-Ab) 5:8
> 5. minor third (C-Eb) 5:6
> 6. major third (C-E) 4:5
> 7. major sixth (C-A) 3:5
> 8. perfect fourth (C-F) 3:4
> 9. perfect fifth (C-G) 2:3
> 10. octave (C-C') 1:2
> 11. unison (C-C) 1:1


So why is there no minor 2nd on this list, are you saying it is not important at all?


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## tdc

tdc said:


> So why is there no minor 2nd on this list, are you saying it is not important at all?


Actually, as I thought about this I think I know why...minor seconds don't occur in strict _tonal_ music, but in _modal_ music??

Maybe. But minor seconds are still in a lot of tonal music...


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## millionrainbows

tdc said:


> So why is there no minor 2nd on this list, are you saying it is not important at all?


It's unusual. Remember, all these relations are derived from relations of root (I) to whatever scale degree is above. It's unusual to have a scale with a minor second as the second step, but in phyrigian mode this is possible (E-F-G-A-B-C-D), if you are prepared to "give it a functional step," but traditionally, tonality and its functions are based on major/minor scales & chords. Or unless you are Miles Davis in _Nardis,_ in which case we can allow it.


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## Bettina

millionrainbows said:


> It's unusual. Remember, all these relations are derived from relations of root (I) to whatever scale degree is above. It's unusual to have a scale with a minor second as the second step, but in phyrigian mode this is possible (E-F-G-A-B-C-D), if you are prepared to "give it a functional step," but traditionally, tonality and its functions are based on major/minor scales & chords. Or unless you are Miles Davis in _Nardis,_ in which case we can allow it.


Great points! Yes, it is very difficult for a Phrygian mode piece to project a sense of functional tonality. Often, Phrygian pieces sound as if they were written in the key a fourth above (so, for example, an E Phrygian piece would sound like the key of A Minor.) This is very much evident in many of Bach's chorale settings of Phrygian melodies, such as Aus tiefer Not and Christus, der uns selig macht. This also occurs in Debussy's Evening in Granada, in which the Phrygian tonic seems to function as a dominant chord.


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## millionrainbows

Bettina said:


> Great points! Yes, it is very difficult for a Phrygian mode piece to project a sense of functional tonality. Often, Phrygian pieces sound as if they were written in the key a fourth above (so, for example, an E Phrygian piece would sound like the key of A Minor.) This is very much evident in many of Bach's chorale settings of Phrygian melodies, such as Aus tiefer Not and Christus, der uns selig macht. This also occurs in Debussy's Evening in Granada, in which the Phrygian tonic seems to function as a dominant chord.


Well, at least the Phrygian has a stable fifth (E-B). The way Miles Davis did Nardis, it is very tonal, and that second degree sounds exotic, like Egyptian music...


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## doctorjohn

millionrainbows said:


> The roman numerals, which indicate scale steps, are also ranked in terms of importance, meaning their relative consonance or dissonance in relation to I, or in other words, the tendency to want to resolve to I, or the "gravity" of the step.
> 
> These are ranked in order of importance. This is based on intervallic relations of the scale steps to the tonic note.
> 
> 1. minor seventh (C-Bb) 9:16
> 2. major seventh (C-B) 8:15
> 3. major second (C-D) 8:9
> 4. minor sixth (C-Ab) 5:8
> 5. minor third (C-Eb) 5:6
> 6. major third (C-E) 4:5
> 7. major sixth (C-A) 3:5
> 8. perfect fourth (C-F) 3:4
> 9. perfect fifth (C-G) 2:3
> 10. octave (C-C') 1:2
> 11. unison (C-C) 1:1
> 
> So a C major scale's horizontal functions correspond to these harmonic relations; and one can observe how these functions were derived:
> 
> I - 1:1
> ii - 8:9
> iii - 4:5
> IV - 3:4
> V - 2:3
> vi - 3:5
> vii - 8:15
> 
> Their importance in establishing the tonalityis be ranked by the order of consonance to dissonance, with smaller-number ratios being more consonant.
> 
> I - 1:1 (tonic)
> V - 2:3 (dominant)
> IV - 3:4 (subdominant, etc.)
> vi - 3:5
> iii - 4:5
> ii - 8:9
> vii - 8:15


 It should be noted that the major second interval from C to D is a different ratio then D to E within the scale of c major


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## millionrainbows

doctorjohn said:


> It should be noted that the major second interval from C to D is a different ratio then D to E within the scale of c major


What are the ratios? Tell us. Also, what tuning are you in? Pythagoran? In ET, all intervals are identical.

But that doesn't matter, since the interval to tonic is all that matters. C to D, or E to C.

Besides, in ET, C to D is 100 cents, and D to E is 100 cents.

Besides, these functions in tonality are _derived_ from ideal harmonic intervals, and in ET these are approximations. So actual interval sizes are essentially irrelevant.


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