Some questions about music in general

Whistle
1

Does anyone know why the forth and fifth of a scale are called “perfect” while the second, third, sixth and 7th are called “major”?

Why not say, major 4th and major 5th?

Why give a qualifier at all? If it’s a 5th then it’s not a minor or augmented 5th so why use either “perfect” or “major” as qualifiers?

Second.

I was trying to figure out how to make a smooth transition between two tunes. First tune in D, second in E. I wasn’t sure which chords to use and a friend said to use A/B and B in the transition measures.

Thus the chords went from: … D | A/B B | E
first tune second tune.

(What I ended up with was … D | A/B B | B7sus | E)

He explained that you use the 4th of the destination key over the 5th bass then the 5th. Thus A/B B.

I’ve found the above works very well for a lot of transitions but here’s the question. What other formulas can be applied for key signature changes?
What about a four measure transition?

Also, are there formulas for time signature changes?

2

Because in both the minor and major scale, the 4th and the 5th intervals do not change. So it isn’t related to a particular scale. Example, the 4th in C minor scale (any of them) will always be F. The 4th in the C major scale will always be F. Same goes for the 5th. For C major and minor scales it will always be G.

That is why DADGAD can be such a great tuning in Irish music. An open strum produces a bunch of roots, 4th, and a 5ths. You really don’t know whether it is a happy or sad chord. Of course, the melody instruments (and the actual chord progression) would clear up that confusion!

p3

3

Ah. Well that was pretty obvious had I thought about it.

On to the second question.

4

It’s not quite as obvious or straightforward as it sounds. There are different minor scales in which some of the other notes are flattened and some aren’t. The third always is and usually the seventh but the sixth only occasionally and the second very rarely in Western music. Sometimes whether you flatten certain notes or not depends on whether you are ascending or descending.

As for transitions, it depends on how the keys are related.

5

Actually, the 4th and 5th intervals themselves aren’t really “perfect”. They are slightly out of tune in the equal temperament. The 4th is slightly sharp, and the 5th is even more slightly flat, to fit within the octave.

They were called perfect because they used to be perfectly in tune. The only perfect interval that exists in equal temperament now is the perfect octave.

6

It’s about the relationships of the intervals. There are large and small intervals, I’m not sure about the terminology in English, you might call them major and minor, but I’m not sure. The are large and small seconds, thirds, sixths and sevenths. If you think of all the notes of the standard diatonic major scale in C for example, as it has no sharps or flats. It consists of C, D, E, F, G, A, B and c. A ionian scale (the standard major scale) has first a large second C to D, another large one: D to E, a small one E to F, a large one: F to G, another large one: G to A, a small one A to B, and finaly a large one back to C. E to F and B to C are always small as long as you don’t trow in any sharps or flats. That’s why a D scale needs two sharps on F and C to make it a major scale. If you play a D scale without sharps, it becomes a minor, becauce the first third is small, D to F (becauce e to f is small). It’s the same with chords, they usually consists of thirds on top of each other. A major chord has first a large third, then a small third, a minor is the exact opposite. So a D major chord for example would be D, F# and A. A minor would be D, F and A.
The fourths and fifths remain consistent, however, there are un-perfect ones, but they are rare.

Your second question is a bit trickier, I’ve only just begun to study this, but here it’s the relationships of the chords you need to consider. Different chords has different roles, and one chord can play any role depending on what key you’re in. A dominant chord will want to lead back to the tonic, so you’re best bet is to trow in the dominant for the key you want to switch to and then go to that tonic. I’m sorry I can’t explain better, which I had paid more attention in school lately.

7

The first question was merely regarding terminology. I understand all the basic chord theory stuff. Just didn’t know why 4ths/5ths aren’t called major 4ths/5ths.

I didn’t want to open the “temprement” can of worms. :boggle:

As Wombat said, there are a lot of chords where the 5th isn’t “perfect”. Diminished would be a good example. I believe all the intervals are minor 3rds.

The second is the real puzzler. Essentially the transition I explained is as Henke said. Using the new key as the root insert the subdominant followed by the dominant.
I figure there are other types of transition. I’ll have to experiment or wait for rh to post.

8

You are talking about modulation, and there are many ways to do it. Ask an organist if you want the full glorious version. The short version is: Do what you want so it sounds good to you, and all ways drop into your destination chord from the fifth above. That establishes tonality more than anything (so you’d want to avoid dropping into your old tonic from the old dominant during the transition).

But what kind of music is this for? If you are accompanying tunes, the best thing is to stop. Take breath. Start playing in new key.

9

AKA “Diabolus en musica” :devil:

10

4ths and 5ths don’t really denote the tonality of the chord – they’re “open” intervals. In addition to perfect 4ths/5ths there are augmented 4ths and diminished 5ths (which are the same interval). But the major and minor qualities of a chord come primarily from the 3rd and 7th – which is why in voicing chords the 5th is usually the first chord member which is dropped.

The fifth is very strongly suggested by the root of the chord because it is prominent in the overtone series – which might be the reason for its “perfect” moniker (third strongest harmonic with a ratio is 2:3 where the fundamental is 1:1 and the octave is 2:1). Also a perfect fifth inverted is a perfect fourth, where a major third inverted is a minor sixth, major seventh inverted is a minor second, etc. So the “open”, consonant quality is pretty stable in that interval.

Once upon a time, perfect fourths and fifths were the only intervals considered consonant, and thirds (which to us define the major/minor quality) and sixths (which to us “sweeten” the chord) were considered horrid dissonant noise.

As Wombat said, there are a lot of chords where the 5th isn’t “perfect”. Diminished would be a good example. I believe all the intervals are minor 3rds.

In a diminished chord, yes, though the dim 5th or “tritone” contained within was known as the Devil’s interval because of its dissonant quality.

The second is the real puzzler. Essentially the transition I explained is as Henke said. Using the new key as the root insert the subdominant followed by the dominant.

This is basically what we were talking about not that long ago, transitioning to a new key imposing a IV/V/I cadence in that key. The B chord in D major is a minor chord, by altering the third of the chord (raising the D to D#) you set up the cadence to the new key, in this case E. It worked nicely because the A major chord is already there in the key of D as the dominant, so you used that as a sort of pivot toward the dominant in the new key. It wouldn’t have worked so well to go from C major to E major, for example.

I figure there are other types of transition. I’ll have to experiment or wait for rh to post.

Hahaha … well, thanks for waiting but i don’t have too much new to add to the discussion here. A lot of modulation is based on the circle of fifths and the IV/V7/I or ii/V7/I formulas, or extending the chord structure to include 9ths, 11ths, etc, to give you more possibilities but those are not real trad sounding.

11

rh, you’ve attempted to respond to all the theory questions I’ve seen so far so I figured it wouldn’t be long :smiley:


So it’s called Modulation. OK. Now I know what to search for. Like most things musical I learn as I go. Maybe a music theory class is in order.

Bloomfield, it’s not for any particular genre of music. I was putting together a couple hymn type tunes in the case above. It’s mainly a theoretical exercise. I like to know how it works behind the scenes.


Thanks to all. I think I’m pointed in the right direction.

(my next question will be on the use of “slash” chords to get that chord walk feeling, i.e. A/B etc etc. I see it a lot on sheet music.)

12

you’d probably really enjoy a theory class – there’s a lot of good theory resources on the web too, for example see this article on slash chords:
http://www.ibreathemusic.com/print/136

13

Sorry Kiddies, but the 4th, unlike th 5th, is NOT “perfect”. It can be augmented as per Lydian scale, just to give one example relevant to Western music

And so it goes …

14

What’s a Lydian “scale,” big Daddy?