First some context: I'm a novice to music theory. I have quite some years of electric guitar playing "by ear" and right now I'm starting to get very interested into the theory behind it (I feel like I've hit a wall and I want to understand this more deeply).
I have come across the idea of scale modes and I think I get a grasp of what they are.
One of the things that strikes me as weird is that in "everyday" music we seem to mostly find the Ionian and Aeolian modes.
Is that the case? If so, why?
One of the things that strikes me as weird is that in "everyday" music we seem to mostly find the Ionian and Aeolian modes.
Is that the case?
It depends on what you are seeing as 'everyday' music, but I think that's half true at best. If you look at Western music of the last few hundred years, there's certainly a lot of music that uses the major scale, which you could say corresponds to the 'Ionian'. There's also lots of music that uses minor tonality - but minor tonality has developed into something more complex than just the Aeolian mode, as the 6th and 7th can be raised or not. In more recent years, the blues scale has become an important influence on a lot of popular music, and that's something different again.
Then, as vjones says, there is plenty of modal material if you look for it - Jazz and Folk music are full of (non aeolian/ionian) modal stuff. If you search for examples of music in each of the modes, you'll find some you know (perhaps not in the Locrian!)
Finally, of the many commonly-known scales, the modes (including Ionaian and Aeolian) are only a small subset of the possibilities. It's not as if we are in a situation where the modes are the only 8 possibilities.
Another aspect is that there's a tendancy in the way Western music theory is taught to try to fit as much as possible into 'Major' and 'Minor', sometimes stretching and developing these concepts to 'make things fit' - so in reality, both things that are described as Major and Minor incorporate a number of different types of tonality.
That's not really the case if you consider all styles of music. The modes are used quite a bit in jazz and rock music. For example, D dorian and Eb dorian can be used directly in improvising over Miles Davis' tune "So What". Dorian in particular is used quite a bit in modal jazz. Keep in mind that other scales like the melodic minor can also be subdivided into modes and those modes can be quite useful as substitute scales in many situations.
Let me put it this way: when a jazz musician says "I'm playing in mixolydian" and when a person who specializes in renaissance music says "I'm playing in mixolydian" they are saying two different things.
In this sense there is a difference between "the major scale" and the "Ionian mode", at least in connotation. The former implies music that is constructed around and involves a particular set of harmonic (chord/key) relationships, whereas the latter is music that is constructed around a set of melodic and contrapuntal relationships.
Ultimately the reason is cultural: for some reason western music, esp. popular music, has really glommed on to the major/minor tonal thing -- music organized around harmonic structures and motion. Language purists will bristle at describing this type of music as being "in a mode" as an anachronism.
I'd describe your observation as everyday music has either major or minor tonality.
TL;DR Pop music isn't really ionian or aeolian, but does have a limited set of notes it uses. There are a few reasons why.
I won't disagree that modern pop music certainly has a specific tonal palette, but I think the analysis that it's based off of the ionian and aeolian mode is a little off. Most pop music isn't that modal at all, it's more chord based and "scales" change all the time based on context.
In cookie cutter minor pop music major 6ths and 7ths are common1 (even more so in classical music.) (not aeolian)
In major pop music, flat 7ths are found aaaaall the time, often in the same song as major 7ths2. A minor 4 chord in a major key isn't super uncommon either3.
There absolutely is a common theme though. In "radio pop" the third doesn't change (stays major or minor depending on the song). The 6th and the 7th can be whatever you want. The second is never flat. The flat 5 isn't used.
So a pop song in C can contain:
C, D, E, F, G, Ab & A, Bb & B (ionian plus Bb and Ab)
or
C, D, Eb, F, G, Ab & A, Bb & B (aeolian plus A and B)
I'm giving no reference with this, it's just what I've noticed over the years from living a radio filled world with musically trained ears, I imagine that everyone here will agree with this analysis (I hope).
Chordally, it will be based around triads (major and minor chords). You might see a dominant 7th on the 5 chord 4, or minor 7ths on the 1, 4 and 5 chord5, but only where these are "non controversial" i.e. they don't add in a note that wasn't in the above scale anyway and therefore do not change the harmonic "flavour". You are not going to have diminished chords, minor sixth chords, half diminished chords, major 7th chords etc. etc. etc.
So your question phrased more accurately might be:
"Why are the both 6th and both 7ths heard in pop music, but not both 2nds or the 4ths. Or really the 3rds (one or the other per song). And why are minor 7th chords heard, but never major 7th chords, never minor 6th chords or their inversions?"
The answer to that is, I'm not sure, but I have some ideas.
first of all, the harmonic series. This explains why no one is playing music based on tritone chords, but doesn't explain why pop music and, say, indian classical music, sound different.
If you'd asked me a year ago I'd have said because pop music is heavily influenced by the guitar, and mainly uses chords that are easy to play on a guitar, it's just what naturally comes out when people write by ear with open guitar chords. But now I'm getting into latin music, which is equally "just written by ear by people with guitars" music, I realise that it follows completely different conventions. In latin music the minor sixth is king. Many common harmonic tricks from pop music are rare or absent, but other simple latin tricks (like a minor 1 chord changing to a major 1 chord to lead to the minor 4 chord.) would NEVER happen in pop music. There is nothing more "complex" one or the other, it's just the way it is. I'll be damned if I know why.
Other people might answer in terms of theory from the classical tradition. But many things that are common in pop music have no precedent in the classical tradition, such as a chord based on the flat 7 of the key, or using a minor 7ths as a tonic chord.
I would say, a bit of all of the above is true, but also, fashion and convention. People write music that sounds like the music they are hearing. Pop music does get a lot from western classical music, and also from folk music, and (to a much lesser extent than in the past) blues music. Conventions stick around because of habit. Innovations happen sometimes, a popular song doing something that sounds good and is different might become a part of the popular idiom (a more trivial example of this which isn't harmonically different to previous music but demonstrates the effect of musical idea propagation is "the millenial woop"). The beatles had a few innovative tonal tricks that are now pretty mainsteam for example. Things go out of fashion too. For example, you hear a lot less seventh chords now than in, say, 70s music. On the other hand you have a lot more leading tones (sharp 7) in minor songs than in the 70s i.e. minor songs are less aeolian than they were, people seem to be reborrowing from classical music in that sense, (probably because more of the actual songwriters of songs on the radio are people who have had at least some formal music education, which involves theory based in the classical tradition).
in case it's easier for you here's all those intervals in C
1 A natural and B natural in C minor
2 B flat in C major
3 an F minor chord in C major
4 G B D F
5 C Eb G Bb F Ab C Eb and G Bb D F
6 Bb Chord in C.
"Once you've played a folk song, there isn't much you can do except play it again, louder."
Extended pieces of music require development of musical material, and require architecture rather than just meandering along. Western music has built a method of doing this largely based on key contrasts. This requires functional harmony. Which requires modes that contain dominant chords and leading notes.
This isn't the only way. Alongside Bach's complexity, Beethoven's dramatic contrasts, the more colourful harmonies of the Romantic composers - modal tunes have still been sung in the streets, and other cultures have developed their own 'classical' traditions. But the 'major/minor' tradition captured the ear of Western listeners for a long time, and has by no means gone away, despite the contempt of the musical establishment.
