Theory & Impro 251

[progger]

Turf's solid post emphasizes an important post that I kind of alluded to in the "by ear vs. written" thread: analytical theory is much more difficult to understand, and also much less useful, without some intuitive musical context. The theory doesn't prescribe what to do in music, it describes what has been done, and it's been done for no other reason than that it sounded good to the person making it.

 

[Pete Thomas]

but whose actual chords are ii min 7, V7, I - so, d min 7, G7, C in the key of C - the three chords using the same set of notes - no sharps or flats.

I don't wish to get more complex but it's worth pointing out that a (diatonic) 251 in a minor key will use the chords of the minor scale (usually the harmonic minor). So in C minor the 251 uses the notes of the minor scale and we get Dmin7♭5 G7 Cmin.

As @turf3 pointed out not all 251s are diatonic (ie sticking to notes of the key or key center).

 

[JSL]

In terms of 'terminology', I think @skeller047 made an important point. "2-5-1" refers to the roots of the chords. Arabic numerals are used when referring to specific notes. When referring to the actual chords, Roman numerals are used. In this case (assuming 7th chords): IImin7-V7-Imaj7.

Or in other words, YES, you can take a C major scale and derive a chord from each successive note of it, that uses only the notes in the C major scale; C major, D min7, E min7, F maj 7, G7, A min7, B min7b5; but that does NOT mean that all the chords in the key of C are those chords. In a sense, that "you can make all these chords out of C major" is really sort of a party trick more than something you can make immediate use of as a performing musician.

True. As Pete pointed out above, when using chords with only the notes from a specific scale (major scale, in this case), they are diatonic chords. But with the 2-5-1 progression, it's not uncommon to use notes & chord tones that are not diatonic. Especially with the V chord, where chord tones are often altered, especially the extensions. But it's important to know the basic, diatonic chord tones first. And go from there.

I want to add that the IImin and V7 chords in a 2-5-1 progression are largely interchangeable, but that's probably well beyond the scope of this discussion. If the OP wants an explanation, I'll be happy to provide it. At the risk of confusing the issue.

 

[turf3]

I don't wish to get more complex but it's worth pointing out that a (diatonic) 251 in a minor key will use the chords of the minor scale (usually the harmonic minor). So in C minor the 251 uses the notes of the minor scale and we get Dmin7♭5 G7 Cmin.

As @turf3 pointed out not all 251s are diatonic (ie sticking to notes of the key or key center).

Yes, I left out minoir 2-5-1s because there are so many variations - for example, you can have Dm5b5 - G7 - Cm, OR you can use a Gm or Gm7 instead of the G7. Once you get into minors, the point that you have to LISTEN and play things that sound good is even more important.

 

[Pete Thomas]

Yes, I left out minoir 2-5-1s because there are so many variations - for example, you can have Dm5b5 - G7 - Cm, OR you can use a Gm or Gm7 instead of the G7. Once you get into minors, the point that you have to LISTEN and play things that sound good is even more important.

True, but I was only wanting to talk about the most common, which is based off the harmonic minor scale.

 

[JSL]

for example, you can have Dm5b5 - G7 - Cm

Hey turf, I think you have a typo there. It should be Dm7b5 (not Dm5b5) or am I missing something? In any case, your point is well-taken.

The minor 2-5 is also common within a major key when it's IIIm7b5 -VI7. Again, not entirely diatonic.

 

[turf3]

Hey turf, I think you have a typo there. It should be Dm7b5 (not Dm5b5) or am I missing something? In any case, your point is well-taken.

The minor 2-5 is also common within a major key when it's IIIm7b5 -VI7. Again, not entirely diatonic.

Yes, Dm7b5. I'm clunky with that because I use the alternate name "half diminished" in speaking, but I don't have the half-diminished symbol readily available on my puter.

 

[Pete Thomas]

but I don't have the half-diminished symbol readily available on my puter.

Here's one I prepared earlier: ø

You can copy and paste. (I think)

 

[mizmar]

On Android, long press 'o' provides the option of 'ø' - which is a vowel Norwegians can hear... Apparently

 

[turf3]

There are vowels in Norwegian?

 

[mizmar]

There are vowels in Norwegian?

More than necessary

As opposed to '∅' of course, which which is zero, probably the correct symbol, and you'd need to make smaller/superscript... ^∅

 

[JSL]

Yes, Dm7b5. I'm clunky with that because I use the alternate name "half diminished" in speaking, but I don't have the half-diminished symbol readily available on my puter.

Got it. And yeah, I don't have that symbol either. I have to admit, while a simple symbol is handy, I prefer 'm7b5' because it specifies the chord tones b7 & b5. I do agree that when speaking, 'half diminished' might be more euphonious and also it is fairly descriptive. To get to 'full' diminished, you'd have to lower the b7 by a half step.