Whatr's this six-note scale called?

[Charlie Bernstein]

(Sorry about that typo. Can't figure out how to edit the title. Grr.)

Just invented a little piece I call "A5" because I play it on an A5 and the tune is based on an A5 chord, a.k.a. an A power chord: the A and E notes, with no major or minor third.

The other chords are the usual suspects: G and Em on the verses, plus C and D on the chorus.

For the chorus, I'm playing the chords' scales, but for the verses, I'm just using a six-note scale: A B D E F# G (A).

Do you know what that scale is called?

Thanks!

[Tobin]

I'm not sure that particular scale has a name, but it is basically a G major scale without the C. Based on your description of the chords you're using, I'd say the tune is in A Dorian mode. Basically, the key of G (same sharps/flats as G major), but based on the ii chord. This mode naturally lends itself to playing that A chord as an A5, neither major nor minor.

[Jacob]

Mixolydian Mode in A - without the 3rd (C#) ?.

[sblock]

If you are quite sure that your tune happens to be in the key of A, and not something else, then the scale consisting of:

AB(C)DEF#G

would be considered A-Dorian mode, but missing the C note.

It could also be

AB(C#)DEF#G

which is A-Mixolydian mode, but missing the C# note.

Both of these modes use a G note, and not G#, in the key of A-major.

Since you are playing a G note, and not a G#, that means it's not in A-major (or A harmonic/melodic minor, either), which uses these three sharps: C#, F#, and G#. Also, it's not any kind of pentatonic or blues scale.

My best guess is that it might be Mixolydian, but who knows? Without seeing the melody and your preferred harmonization, there is not enough information to go any further.

[KirbyCool]

As others have said, with an A root, the scale is ambiguous because it's missing the third and I don't think it has formal name. Harmonically, this is spelling out Asus13. My guess is you're going to hear an implied C natural (A dorian) because as you mentioned, the song is in a G major mode.

But the cool part about harmony like this is, as an improviser, you have a lot of room to play with it! If the chordal part is just playing 1 and 5, you can play all sorts of A based scales without clashing with the backing instruments. Try messing around going back and forth between major, minor, dominant, non dominant etc.

[foldedpath]

This may be what I've heard referred to as a hexatonic tune, or a tune in a "gapped scale."

There are tunes like this in Irish trad that defy easy categorization as major or minor/dorian, for lack of a third. Drives guitar backers nuts, trying to figure out the chords...

[Tobin]

He did mention that he's using a C natural (major, presumably) chord, so the "missing" third isn't really missing in the tune, even if it is missing in the scale he mentioned. So a C# seems to not fit here.

[StuartE]

You could call it (a mode of) D Major hexatonic. Rearranging D E F# G A B D. (See wikipedia.

Another way to look at it is two triad D and E minor. Also the A sus 13 seems viable to me.

Jazz saxophonist Jerry Bergozi has written a book on hexatonics. I haven't read it.

[Charlie Bernstein]

This may be what I've heard referred to as a hexatonic tune, or a tune in a "gapped scale."

There are tunes like this in Irish trad that defy easy categorization as major or minor/dorian, for lack of a third. Drives guitar backers nuts, trying to figure out the chords...

Yup, it has a Celtic sound to it. I have a friend who plays zook and DADGAD guitar, and he gets similar voicings. I like "gapped scale," since there is a big gap where the third should go.

[Charlie Bernstein]

He did mention that he's using a C natural (major, presumably) chord, so the "missing" third isn't really missing in the tune, even if it is missing in the scale he mentioned. So a C# seems to not fit here.

Yes, the C and D are in the chorus, where I'm just using major scales. The verses are just A5, G, and Em. So there's mood contrast (that old tension/release thing) between the verses and choruses.

So you're right, the C isn't really missing, it's just hanging back to make a dramatic entrance.

[Charlie Bernstein]

You could call it (a mode of) D Major hexatonic. Rearranging D E F# G A B D. (See wikipedia.

Another way to look at it is two triad D and E minor. Also the A sus 13 seems viable to me.

Jazz saxophonist Jerry Bergozi has written a book on hexatonics. I haven't read it.

Whew! This is getting REALLY interesting!

[Tobin]

Yup, it has a Celtic sound to it.

I suspect that's because the Dorian mode is the most common mode used in Irish music.