Today's theory lesson will revolve around pitch & rhythm, and follows on from the previous lesson on measures & bars.

0. Contents
1. The pitch/rhythm axis
2. Pitch
3. Rhythm
4. Summary
5. Related lessons & resources

The Pitch/Rhythm Axis

Let us begin by firstly defining what written music is: musical notation is the organization of pitch & rhythm in a visual medium. Pitches are written on the staff in the form of musical notes that tell the user what pitch to play, and for how long. Looking at the diagram below, you will see that pitches are written vertically and rhythm is written horizontally, this concept can be thought of as the pitch/rhythm axis.

Pitch

In order for a composer to accurately communicate the musical piece, there are a number of other elements that must be defined before we start with the actual written music. The first of these elements is the clef, a clef is a symbol at the very beginning of the music that defines what tonal range the piece is in, and the most common of these are the treble clef and the bass clef. In the example diagram below you will see that this piece is in the treble tonal range, to which the guitar belongs. The treble clef defines that the note G is to be referenced on the second line from the bottom, and that the musical alphabet is to be continued upwards from this note. The musical alphabet is A, B, C, D, E, F, G (the first seven letters of the alphabet) at which point we return to the note A after we reach G, and repeat the seven note sequence.

The next element is the key signature, a key signature is one, or a series of sharp() or flat() symbols that define which notes (relative to C major which has no sharps or flats) are to be sharp or flat, which will then tell the user what key the music is written in. In the example below, the key signature tells us that the notes C, F and G are sharp, an experienced musician can tell from this that the key is A major, and you will be able to know this too after practice.

The last element is called the time signature, a time signature is a set of two numbers, one on top of each other, that tell us two things, the top number is the number of beats per bar, and the bottom number is which note gets the beat. Looking at our example below it says ⁴/₄, which means the there are four beats per bar, and that those beats have the value of one quarter note each. The bottom number comes from the lower number of a notes fraction, for instance, the fraction of a quarter note is ¹/₄, so we just take the 4 to signify a quarter note. In ⁶/₈ timing there are six beats per bar and each beat has the value of one eighth note each.

Rhythm

When it comes to defining the rhythm of music, it's all basic mathematics really. Using a quarter note as our divisor, which means that all note values are relative to a quarter note. Keeping this in mind, below you will find the musical note division table which starts off with a whole note/semibreve that has a value of four quarter notes. Next we have a half note/minim which has the value of two quarter notes, then we have our quarter note/crotchet which has the value of itself, as this is our divisor. We then have an eighth note/quaver which has the value of half a quarter note, and lastly we have a sixteenth note/semiquaver which has the value of one quarter of a quarter note. There are also 32^nd notes and 64^th notes and we will learn these in our next lesson.

 

So as you can see, the rhythm of music really is just basic mathematics, we simply divide the time into fractions. Now let's learn some simple note addition examples below just to reinforce what we have done so far.

Musical Note Addition Examples
Notes	Equals	Result	Comments
+ +	=		One quarter note plus two eighth notes equals one half note
+ + +	=		Four eighth notes is equal to one half note
+ +	=		One eighth note and two sixteenth notes equals one quarter note
+	=		Two half notes equals one whole note
+ + +	=		Four sixteenth notes equals one quarter note

Summary

I hope you enjoyed the third part of my music theory lessons and be sure to follow on to the next: Pitch notation.

Cheers & enjoy!

Related lessons & resources

• Guitar Lessons
• • Rhythm, timing & strumming techniques

• Music Theory
• • Staffs, clefs & ledger lines
  • Measures & bars
  • Pitch notation
  • Rhythm notation
  • Rest notation

External Resources

• Pitch at Wikipedia.org
• Rhythm at Wikipedia.org