Tetrachords

Hello and welcome back. I'm Joseph Hoffman.
Today we're going into new music theory territory by learning a new kind of scale called the tetrachord.
What is a tetrachord?
Well Tetra is a Greek prefix that means four like the number four.
So a tetrachord is a family of four notes all one step apart.
By the end of today we're going to learn how to combine two tetrachords to build a full eight note or one octave scale.
Let's come to the piano to check it out.
Here I have drawn the C major tetrachord.
You'll notice it's just one key different from the C major pentascale,
which we're very familiar with.
Tetra means four, so we just go up these four notes. DO RE MI FA
Putting the half step here at the top of the tetrachord.
Now, in music very often we want to go a full octave.
Remember, oct means eight,
and to go an octave that's going to be eight notes. Four plus four more.
So if you put two tetrachords together,
like this, you can get a full octave scale.
So down here we have C D E F, and then up here we have G A B C.
Now let's notice some things about these tetrachords.
You'll notice that the top two notes of this tetrachord form the half step.
Same thing with this tetrachord.
Two notes at the top make the half step.
You put two tetrachords together like that, and that builds a one octave major scale.
So this is cool because it will open up so many new songs that we can perform when we can go the full octave.
Now in solfège, let's give a name to each of these notes of the octave scale.
we have DO RE MI FA SO LA TI DO
Now can you try that with me? Ready go: DO RE MI FA SO LA TI DO
Good, now let's come down the octave scale like this: DO TI LA SO FA MI RE DO
Now try that with me. Ready going down, go.
DO TI LA SO FA MI RE DO
Good job. Now on your own I'd like you to practice that singing up the octave,
down the octave, whenever you're feeling bored
just start singing some solfège octave scales.
Now let's talk about how to play these two tetrascales, which again form a one octave major scale.
I'm going to use my left hand fingers 5 4 3 2 on C D E F, and notice my thumb is not needed.
My right hand I'm going to use fingers 2 3 4 5 on G A B C, so once again
our thumbs are not needed in either hand. We only need four keys, four keys, so the thumb gets to take a break.
Okay, so now will you find this position with me?
With your left hand fingers 5 4 3 2 cover up C D E F, then right hand is just on the next adjacent four white keys: G A B C,
and it's going to go like this: DO RE MI FA SO LA TI DO
Can you play that with me, and let's sing the solfège. Ready, go.
DO RE MI FA SO LA TI DO. Now let's come down, ready, go:
DO TI LA SO FA MI RE DO
Nice job, this time let's sing the letter names.
Ready, go. C D E F G A B C. Now coming down:
C B A G F E D C
Now, if you didn't quite get that feel free to press pause and try that a couple more times on your own.
Otherwise let's keep going.
Now, this is called the major one octave scale. We're going all the way from DO
to DO. Low DO, which is C, to high DO which is C, and then we could keep going up from there.
DO RE MI FA SO LA TI DO
Can keep going all the way up the piano.
Now I'd like to teach you a really short song that will just be to practice these tetrachords,
and then we're going to transpose this song eventually into all 12 major and minor keys.
The song goes like this. It's called "Follow Me".
♫Follow, follow, follow, follow me♫
♫Let's make a line for all to see♫
That's the whole song.
Really short. Like I said it's just to practice these tetrachords.
Now let me show you how to play it.
The song goes: DO RE MI FA SO SO
DO TI LA SO
FA FA FA MI MI RE RE DO
Or with lyrics:
♫Follow, follow, follow, follow me♫
♫Let's make a line for all to see♫
Now you might be asking, where's the sheet music Mr. Hoffman?
Well, this song I want you to learn by ear.
It's important to be able to learn songs both by reading from a score from the sheet music,
or by just figuring it out by hearing it and imitating it.
Now, if you'd like using the materials you can get from our website, you can get a blank
staff that you can notate it yourself, which I challenge you to do. So you write down the notes for yourself.
So let's try to play "Follow Me". Can you cover up these two tetrachords with the right and left hand?
I will sing a pattern, and you try and play it back.
So we're going to have DO RE MI FA SO SO. Now you try.
Good, and you'll notice before we would have played that like this,
but now when we get to SO we're going to shift over to the other hand so you only have four notes per tetrachord.
DO RE MI FA SO SO. Try that one more time.
Good, then we skip ...