After chatting with a couple members in the chat room (those of you not jumping in there are missing out on some good discussions!), I decided to put together a little illustration on the benefits of understanding how particular chords make a key.
I would recommend that in addition to this little illustration you check out Fretsource's lesson on the Circle of Fifths (
The Circle of Fifths
and
the basic lesson found here:
http://www.guitarforbeginners.com/chords.html
Now, with a basic understanding of how a key is defined, let's look at the key of C and the chords from which it is comprised:
C Dmin Emin F G Amin Bdim
When developing a chord progression, one of the basic foundations of music, it is a good idea to know what key you are using as it will help you to find that chord that will fit just right in each place of the song.
The attachment here is a sample of a chord progression using all of the chords in the key of C. First I played through the progression just strumming each chord, then a couple times through with some chord embellishments and little runs to spice things up a bit. How long did it take to come up with that little ditty? About 2 minutes- because I know the key! If you learn the keys, you will be able to come up with interesting progressions in very short order as well.
Here's the progression used in the example:
"verse" : C Bdim Amin F C G C (repeat)
"chorus": Emin Amin Dmin G
As you can see, all of the chords in the key of C were used- this is not to say that your chord progressions need to use all of the chords in a key (there are thousands of songs with just 3 or 4 chords in them). The purpose was to show how they all fit together nicely.
Hope this helped some of you get a little better understanding of what keys are all about as well as their practical purpose!