Re: [Harp-L] What's a "key"?



On May 5, 2011, at 7:03 PM, sheltraw@xxxxxxxxxxxx wrote:

> On another thread the question of how to determine the key of a tune was
> raised. So I would like to ask two questions of importance to that thread.
> 
> (1) What do you think the term "key" means?

I don't know how musically savvy you are, so this is either a very clever
question designed to make us think rather deeply about musical theory, or
you really don't know, and you're trying to find out.

I'm going to answer as if you're asking the second question: "No, really,
what _is_ a key?" I have not formally studied musical theory and I am
only learning to read music, but I find musical theory fascinating, so
I hope my fellow Harp-ellers will forgive a new guy for going on a bit.

Like much in music, there's no simple-simple answer (with all due respect
to Rick Dempster's eleven-word answer), but you can learn enough to be
somewhat useful to you in relatively short order.

If you're familiar with the "do-re-mi" system for naming the notes in
a major scale, then a familiar three-note chord (the "triad" mentioned by
Rick) consists of do, mi, and sol. In the United States, the "do-re-mi"
system is "movable", meaning that the note "do" does not refer to a
specific note, such as C, but to the first note in the major scale: the
"first scale degree".

Thus, in the scale of C:

   do  = C
   re  = D
   mi  = E
   fa  = F
   sol = G
   la  = A
   ti  = B

And the C major chord (do-mi-sol) is C-E-G.

Obviously, there are also minor scales and minor chords, but that's
beyond the scope of this email. This Wikipedia entry is helpful:

    http://en.wikipedia.org/wiki/Scale_(music)

Because this is such a quickly-written and brief summary, it would be
easy to confuse musical key (the "tonal center" around which a song or
a passage may be composed) and scale, since they use the same names.

The C major *scale* drawn out above (C-D-E-F-G-A-B) is just the major
scale starting with C.

A piece of music that is "in the *key* of C" ("major") would be written
so that it "comes home to", or "is centered on" or (as Rick says)
"resolves to" the C-E-G triad, the C major chord.

What constitutes the "key of C" is somewhat harder to put your hands
around than the C major scale: it is not a specific set of notes or
even a specific sequence of notes, but is more the "center of gravity"
(as a Wikipedia author puts it) that drives the chord progressions in
the song or passage.

The reason we can have a longish thread about the topic of "finding the
key" of a song is that composers don't just bang out a chord in the
song's key at the start, but dance around it, so to speak.

Each musical key has a set of chords (including, but not limited to the
chord that shares the key's name) that tend to appear together, because
they "work" together to establish a particular feeling or style.

Knowing the kind of music you're playing and the "characteristic chords"
for each of the 12 major and 12 minor keys in that style might allow you
to (fairly accurately) figure out the key of the song before you get to
the point where it "resolves to" the song's key.

But that's a lot harder than it sounds, at least for me: for each of the
24 keys, there are at least three and possibly seven or more sets of
chords that fall under that key, not taking into consideration that the
composer might get creative and throw some oddball stuff in there just
to make it interesting.

AND that's not taking into account the player's ear: whether or not you
can hear a G minor chord and know that's what it is.

Here's an interesting (to me, anyway) piece that I found a long time
ago (while learning to play the Ukulele) that talks about which chords
are "in" a key. Though written on a guitarist web site, it covers the
topic thoroughly enough to give you a flavor:

    http://www.ultimate-guitar.com/lessons/chords/what_chords_are_in_what_key_and_why.html

Wikipedia's entry for Key (music) is much better researched and written,
and is definitely worth a read:

    http://en.wikipedia.org/wiki/Key_(music)

At the bottom of that Wikipedia entry is a link to "A simple, but
accurate, explanation of the function of 'keys' in music" that does a
nice job of explaining the complex interplay of notes and chords and
harmony that make up musical keys:

    http://ask.metafilter.com/mefi/6444#132028

> and
> 
> (2) Given that you have identified the "key" then what are you going to do
> with that information?

I'm going to pick out which harp to stick in my mouth: Once I know
the key of the song, then I can pick out a harp so that it's easy to
play along.

Of course, that's not as simple as you might like, either. If the
song is in C, then I'm going to pick up a G harp, because I harmonize
most easily by playing in the second position.

As you may know, each harmonica is stamped with the instrument's
key. (Instruments are in keys, too. A diatonic harp doesn't have
every note in the scale on it, but repeats patterns of notes that
*are* there to make it easy to play chords or to harmonize with a
song just with the notes on the harp).

The key stamped on the instrument is its "first position" key --
think of how you might pick up a harp and blow "Oh, Susannah" on it:
that's first position.

Second position is favored by blues players: it is a fifth above the
stamped key. A C harp is in the key of G when played in the second
position.

Once you know the key of the song *and* what position you want to play
(I almost always play second position, because I tend to play rock
and blues), you pick a harp that is a fifth *below* the key of the
song (because you'll be playing a fifth *above* the key stamped on the
harp). Thus:

Song in the key of C, playing 2nd position: I need an F harp, because
I'll be playing a fifth *above* the first position F, which is C
(F-G-A-B-C).

See! Clear as mud.

Hope this helped.

Dave





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