How are keys determined ?

Subject: How are keys determined ?
From: Les B
Date: 16 Feb 07 - 06:43 PM

Probably not quite the best title for this, but here's the problem.
The other day I was jamming with friends and the accordion player pulled out sheet music for "Alabama Jubilee" and said "this tune is in A 7th" - I was kind of surprised, but figured since he reads music and I don't he knew what he was talking about.

I started playing along when I realized it's the same old tune I know as being in the key of C. Where the mix-up comes is that the first three notes are individual pick-up notes that run down from a C note to the A7 (the full chord progression of the song is approximately: A7, D7, G, C, A7, Dm, F, C, E7, F, C, D, G, C)

Now, even though I don't read music, I know that the key is usually the last note or chord that the tune ends on - which in this case is obviously C.   What I got to wondering afterwards - AND HERE IS MY QUESTION - I've never heard of tunes being in the key of a seventh, or a 9th or a 13th, or an augmented or diminished - ie, C7, D9, E +, etc., but I have heard of tunes being in the key of A minor, or E minor, etc.   Why do minors get to be a "key" and the other coloration of chords do not ??

Subject: RE: How are keys determined ?
From: Jack Campin
Date: 16 Feb 07 - 07:18 PM

The key is determined by the selection and sequence of notes in the *tune* - that is, its scale.

A different choice of chords can't change the key of a tune.

Minor chords got the names they have from their relationship to the minor scale, not the other way round.

Your accordionist pal was gibbering.

Subject: RE: How are keys determined ?
From: wysiwyg
Date: 16 Feb 07 - 07:21 PM

A bluesy sound may come from focusing on the 7ths, and he may have been speaking shorthand for the general effect he was aiming for.

~Susan

Subject: RE: How are keys determined ?
From: Bev and Jerry
Date: 16 Feb 07 - 07:28 PM

You are correct that the key of a song or tune can usually be determined by looking at the last note or chord, at least in folk music.

There are 15 keys that a piece can be written in. They have from one to seven sharps, from one to seven flats, or, in the key of C, no sharps or flats. They are named for the first note of the scale which, if played with that number of sharps or flats, would produce a major scale. So, the key named D major has two sharps and produces a major scale if you start on D and play a scale using two sharps.

Each of these 15 keys also has another name. That name is the sixth note of the scale followed by the word minor. Thus the key of C major is also called the key of A minor - they both have no sharps or flats. The only difference between them is in the final note or chord. Pieces written in the key of C major tend to resolve themselves to the C chord and the note C at the end of the piece. Pieces written in the key of A minor tend to resolve themselves to the A minor chord and the note A at the end.

There are no keys called A7, D9, etc.

Bev and Jerry

Subject: RE: How are keys determined ?
From: Kaleea
Date: 16 Feb 07 - 07:56 PM

I once played a jazz piece which was composed in the key of "F diminished," according to the composer, which had one sharp (F#) and one flat (Bb) in the key signature.

Subject: RE: How are keys determined ?
From: Bee-dubya-ell
Date: 16 Feb 07 - 08:23 PM

Lots of people make the mistake of assuming that the first chord in a song is always indicative of the key signature. It usually is, particularly in folk music, but many songs with more swing or jazz origins start with something besides the I chord. ("I" being the Roman numeral for "1", indicating the chord with the same name as the key signature.) If you play the following common songs in the key of G, "Sweet Georgia Brown" starts with an E, "Pallet on the Floor" starts with a C, "Some of These Days" starts with an Em.

However, the final chord in a song is almost always the I chord. The exceptions are tunes which don't "resolve", but that's another kettle of fish.

Subject: RE: How are keys determined ?
From: Don Firth
Date: 16 Feb 07 - 08:38 PM

It would be impossible to cover this adequately without writing a treatise on music theory, but to start with, as others have said here, there is no "key of A7." A7 designates a chord, composed of the notes A, C#, E. and G. Keys are designated by a letter (C, D, Bb, G, etc,) to designate the tonic or tonal note that acts as home-base, and is often followed with "major" or "minor" to tell you the nature of the scale.

More often than not, a tune ends on the tonic or key-note. But not always. Especially in folk music. Whereas almost all classical music written within the last few centuries and almost all popular songs end on the tonic note, much music written earlier than the sixteenth or seventeenth centuries was modal. Modes are different scales that for the most part have fallen into disuse (although some modern composers are tinkering with them). But often some older folk songs and ballads (or their descendants) are modal rather than in the more familiar major and minor scales (which are modes, by the way). For example, if you encounter a song that seems to be in the key of A minor, but you keep having to sing an F# instead of the expected F natural, you're in Dorian mode. Or if the song is in a major scale except that the seventh degree of the scale is a half-step lower than in a regular major scale, you're in Mixolydian mode.

There are threads here on Mudcat that discuss modes at length, but having read through them, I caution that one may emerge more confused than ever. Apart from taking classes in music theory, probably the best way would be to get a copy of something like "Music Theory for Dummies" or "The Complete Idiot's Guide to Music Theory." You don't have to study them grimly. For the most part, you can check the index and look up what you want to know. But studying them a bit ain't gonna kill ya.

Don Firth

Subject: RE: How are keys determined ?
From: McGrath of Harlow
Date: 16 Feb 07 - 08:53 PM

There's no such key as A7 - it would appear Les B's friend just meant "the first chord in this is A7". Which might I suppose be quite helpful - but it'd be better to have said "It's in C, with A7 as the first chord"

Subject: RE: How are keys determined ?
From: Rowan
Date: 16 Feb 07 - 09:20 PM

While the posting from Bev & Jerry is helpful, there is a confusion that arises between the 'classical' use of terms and many folkies' use. Playing just the white notes on a piano keyboard will give you the C major that Bev and Jerry mention. It was also give you two versions of scales that have minor feel; one starts on A and the other starts on D. Others have posted much more comprehensively elsewhere on scales and modes (Don's is spot on) so I won't confuse you beyond mentioning that the classicists refer to A minor as the minor scale relative to C major but, when folkies mention D minor, most of the notes they play will be on the C major scale. Single row melodeons give examples, as do harmonicas.

Cheers, Rowan

Subject: RE: How are keys determined ?
From: Les B
Date: 16 Feb 07 - 10:17 PM

OK, I generally understand that the minor scale indicates the key, and that there are major and minor scales. I just didn't know how to explain to him that there is no such key as A 7.

On a slightly differnt tack, what is the term for those tunes or the beginning of tunes (like this one did)that start on an off chord, usually the seventh. I see this in quite a few rags.

Another friend of mine calls these "phantom chord starts" but there must be a more proper name for this ?

Subject: RE: How are keys determined ?
From: GUEST,leeneia
Date: 16 Feb 07 - 11:02 PM

A lot of people assume that the first chord of a song is the key it's in, but that is not always true.

I think that everyone who wants to play music with others should get a half-hour lesson at a keyboard, learning about keys and chords. Not knowing these basic things is like driving a car without being able to read road signs.

Subject: RE: How are keys determined ?
From: Bee-dubya-ell
Date: 16 Feb 07 - 11:33 PM

I don't know if there's a name for the types of tunes to which you're referring, Les, but I like your friend's "phantom chord" term. Many such tunes start with a "walkdown" that "lands" on the VI7 chord (A7 in C, E7 in G etc.). That walkdown usually starts with the tonic. "Alabama Jubilee" actually starts with a walkdown that goes C,B,A# and "lands" on the A7 chord with the A note. One doesn't actually play a chord during that walkdown, but the chord that's not being played, the "phantom chord", is a C. The walkdown is really just taking place of the chord.

Subject: RE: How are keys determined ?
From: GUEST,Terry McDonald
Date: 17 Feb 07 - 04:39 AM

Fifteen keys? I can only think of 12 major and 12 minor - A, Bb, B, C, Db, D, Eb, E, F,Gb, G, Ab. The scale of C has no sharps or flats, and the key of Gb (or F#) has six. Where are the other three keys, or are you saying that there's a difference between (for the sake of argument), Gb and F#? I've never found them on the guitar (or piano for that matter.) But I'm self taught............

Subject: RE: How are keys determined ?
From: GUEST,Julia
Date: 17 Feb 07 - 04:47 AM

For more music theory than anyone could want, but quite intelligible for all that, try: www.dolmetsch.com

Julia

Subject: RE: How are keys determined ?
From: The Fooles Troupe
Date: 17 Feb 07 - 06:44 AM

"A little knowledge is a dangerous thing"...


especially if it is garbled....