"In the key of 'X'" music theory

What the hell are people talking about when they talk about a song being in "the key of something"?

What affect does this have on a musician's playing?

It means that that note (let's say B if it's the key of B) is the "home tone" which the song is centered around. I'll let someone who's more eloquent about music theory explain it more.

Yeah, it's an easy concept at heart, but not an easy one to put into words.

Very true. It's easiest to explain in person, while sitting at a piano.

Anyway, the point of "keys" is that in music, everything is relative. The key provides a reference point.

For example, let's say you have a tune that's in the key of C, and it consists of the notes C, D, E and G. That same tune in the key of A would be A, B, C# and E. The point is that these tunes, unless you hear them at the same time or shortly after one another (or you have mad absolute pitch skillz), will sound exactly the same. That's what I mean by 'everything is relative': it's the "distance" between the notes that matters.

Which is why it's important to have a reference point. If you're going to play the tune I just mentioned with a group of people, and you don't have any kind of reference point, one person might play C-D-E-G, another might play A-B-C#-E, and a third might play D-E-F#-A. Together, that won't sound so great. That's why you'll say, 'Okay, it's in the key of C', and then everyone will know which notes to play.

This topic got me thinking: we have a thread for asking general music theory questions, but maybe someone could make a "music theory crash course" thread to explain the basics?

I could write something like that... I know enough about the basic concepts to explain them to people. Only it would be a hell of a lot of work, and I wouldn't really know where to start.

Same here, I have no idea how to put the concepts into words. And I'd probably ramble on and turn it into a massive history lesson anyway ("you hardly ever see tritones because using them in the Middle Ages was a no-no", etc).

Anything would be better than nothing.

Let's see... I think it would have to be built up somewhat like this:

- Tones: pitch and duration
- Rhythm
- Keys
- Modes and scales
- Chords

I could help.

As could I.

It just struck me that maybe it would work better as a Useful Notes page than a forum thread...

This may be helpful in learning diatonic keys and how they relate to one another: Circle of Fifths.

Even better.

How does one quote on this forum? Anyways, Master Inferno said:

"you hardly ever see tritones because using them in the Middle Ages was a no-no"

Except in jazz, where they are so ubiquitous it's become a jazz cliche to play with chords that include them.

Put [quoteblock] before what you want to quote and [/quoteblock] after, except use double brackets. I'd use them myself in this post except that I can't get it to not actually make a quote block...

edited 9th Apr '12 3:26:10 PM by MasterInferno

Thanks.

Seriously though, studying jazz in college - we must have spent half a semester on tritones and their uses.

It's double brackets though.

Also, tritones are ridiculously common in Heavy Metal because they're so damn menacing. Come on in, Trope Codifier...

I should clarify then that "no tritones" basically applies mostly to Western classical theory, which is what you'd start off learning in a music class. I've only ever seen jazz theory offered as a separate class, and rock/metal is all "screw the rules, I have attitude" anyway...

Naah, most rock is pretty conventional.

It is. Blues influences aside—hello, microtones!—rock theory is basically just simplified classical theory.

Well you get a tritone any time you use a diminished or dominant chord, so they're not that uncommon, at least in modern music. I can't speak for older classical music.

The vast majority of Classical pieces (especially Bach-type Baroque era stuff) ends with a ii6(5)-V7-I perfect cadence, and the I-vii6-I6 or I6-vii6-I chord progressions were incredibly common, so you'd still see a fair amount of tritones in Classical music.

Wow, I use those all the time and didn't know what they were called.

When I was a kid, I'd read through the entire United Methodist Hymnal. A lot of the arrangements in there are very complex — lots of major sevenths, diminished, augmented, dissonance, etc. I tend to arrange that way when I write, even when I do country songs.

I'd love to hear a country song utilising dissonant counterpoint, actually...