Notes in a Key

Hi All:

My first post. Apologies if there is an archives that I should search of FAQ that would better direct me.

I am trying to soak up all I can on music theory and have one question about which notes are in a certain key.

To illustrate, suppose we are in the key of C major, which obviously includes:

C - D - E - F - G - A - B

My question is whether variants of those notes are also in the key of C. So, for example, is an E dominant 7 in the key of C (since an E major is). Or, is an A-minor also in the key of C.

Thanks for your guidance. I'm very much a music theory noob.

Harold

Hey & welcome to GT!

Originally Posted by: hdoranI am trying to soak up all I can on music theory and have one question about which notes are in a certain key.[/quote]
If you haven't already, I encourage you to go through Guitar Fundamentals 2, which starts with a primer on music theory.

http://www.guitartricks.com/course.php?input=2

Next, this tutorial covers the basics of music theory. It will show you how to determine notes in a key. Further, it shows you how to build the chords that are related to each key. Then you can determine which chords are part of a scale. This is called triadic harmony.

http://www.guitartricks.com/tutorial.php?input=495

When you are ready to get more in depth, this tutorial covers the circle of fifths. It will show you the notes that comprise each of the 12 possible major keys, one key at a time.

http://www.guitartricks.com/tutorial.php?input=835

Now, to answer your specific question.
[QUOTE=hdoran]
To illustrate, suppose we are in the key of C major, which obviously includes:

C - D - E - F - G - A - B

My question is whether variants of those notes are also in the key of C. So, for example, is an E dominant 7 in the key of C (since an E major is). Or, is an A-minor also in the key of C.

The terms scale and key mean virtually the same thing. However, the scale is only the notes:

C - D - E - F - G - A - B

What you can do with them (mix them into chords, etc.) & how they relate to each other is the key of C major.

Next, E dominant 7 is a chord, which is made of 4 notes. So, what you want to know is, "Are all the notes in the E7 chord also in the C major scale or key?"

Here are the notes of E7:

E (1st) - G-sharp (major 3rd) - B (5th) - D (minor 7th)

Since E7 contains the note G-sharp, it is not in the key of C major (all of the notes of the E7 are not contained in the C major scale).

Here are the notes of an A minor chord:

A (1st) - C (minor 3rd) - E (5th)

Since all of the notes of an A minor chord are found in the C major scale, it is in the key of C major. It is the sixth chord; written as a lower case Roman Numeral (vi). This info is covered in depth in the music theory tutorial linked above.

Hope this helps! Let me know if you have any other theory questions. Have fun. :)

This is an awesome response!

Thank you.

Chris

I watch a ton of your videos, thanks for making them. I just realized something. Perhaps this is answered in the links you posted, which I will study this weekend.

I see that the note of E is in the C major scale. But, the E major chord contains the G# as its 3rd.

As you note, G# is not a note in the C major scale. So, does this mean that the E major chord is not in the key of C major also?

I always assumed that because the E note was in the C major scale that also meant that the E major chord was in the key of C as well.

Hi

Try to find a guitar harmony chart I don't know if they have one on this site. I printed out one so I can refer to it without having to look it up on the computer all the time.

There you can see that the e chord is in there but it is a minor the ii,iii and vi are minor in a major key

Hope this helps

/Lars

Originally Posted by: hdoran
I watch a ton of your videos, thanks for making them.[/quote]
You are welcome. Glad you are enjoying GT & my lessons.
[QUOTE=hdoran]
I see that the note of E is in the C major scale. But, the E major chord contains the G# as its 3rd.

As you note, G# is not a note in the C major scale. So, does this mean that the E major chord is not in the key of C major also?

Yes! You've got it right now. :) You have to consider all of the notes in a chord to know if all of them are found in a scale/key. If even one of them is out, that chord is not totally in the key. At that point, you've got an accidental, which is the specific term used for a note that is played in a piece of music that is outside of the main key the music is in.

Originally Posted by: larsm2011There you can see that the e chord is in there but it is a minor the ii,iii and vi are minor in a major key

Thanks for your helpful reply, Lars. :)

All of this info about which chords are in a key are covered in my music theory tutorial. Conveniently, the example is in the key of C major.

http://www.guitartricks.com/tutorial.php?input=495

Also, an example of an accidental, using a chord with notes outside of the key are covered in this tutorial about basic improvization.

http://www.guitartricks.com/tutorial.php?input=876

Chris:

In these lessons you give one very interesting example I'd like to learn a little more about. Specifically, you note that the open A string rings out at 110 hertz and then at the octave (same string fret 12) we have a 2:1 ratio since it rings out at 220.

Now, the E note on the 7th fret is the 5th of the scale and it rings out at 55 hertz (1/2 of the open A). You note that this is as "far from home base" as you can get.

What I'm curious to learn more about is the other strings and the mathematical relationship between all frets. For example, what pitch is the 1st string open E at and what frequency does it ring out at if I press the first fret, second fret, 3rd and so on.

Does such a resource exist?

Originally Posted by: hdoran
In these lessons you give one very interesting example I'd like to learn a little more about. Specifically, you note that the open A string rings out at 110 hertz and then at the octave (same string fret 12) we have a 2:1 ratio since it rings out at 220.[/quote]
Sounds like you are referring to this lesson:

http://www.guitartricks.com/lesson.php?input=13698&s_id=835

The E note on the 7th fret is the 5th of the scale and is 165 hertz. The reason I use the metaphor "as far from home base as you can get" is because it is halfway between the pitches of A above and below. The octaves of A are "home base". If you go any farther up or down you are closer to an A. So, the next thing to do is split the A & E in half.

A - 110Hz
C# - 138Hz
E - 165Hz

Halfway between the root & fifth is the major third. :) The more you study this topic, the more you grasp the basic principle of a continuum on which simple ratios forming consonance & more complex ratios forming dissonance. Music is often a process of starting on consonance, building dissonances (adding drama & tension) aiming toward consonances (resolving & releasing tension).
[QUOTE=hdoran]What I'm curious to learn more about is the other strings and the mathematical relationship between all frets.
...
Does such a resource exist?

Hermann Helmholtz wrote the first definitive book on this topic On the Sensations of Tone as a Physiological Basis for the Theory of Music (1862.

http://archive.org/details/onsensationston00elligoog

Here are a couple of online resources I use for the purposes of studying the relationships between musical pitches.

http://www.phy.mtu.edu/~suits/notefreqs.html
http://en.wikipedia.org/wiki/Pitch_(music)
http://www.vaughns-1-pagers.com/music/musical-note-frequencies.htm

Have fun!