Rhythm and Meter

Rhythm is the most important part of the musical language.  Its notation is a very precise system of describing events in time.  Although we will talk at great length about rhythm and its notation in class, here are some conventions to observe as you transcribe, write, and learn pieces.

Rhythm is created through repetition.  Without repetition, a musical-rhythmic event is isolated and does not create rhythm.  Events that are repeated at intervals in time generate rhythm, like a clock ticking generates a rhythm because the ticks happen at a regular interval (one second).  A metronome ticking away is repeating a click at a regular rate as well, and a piano player who is playing notes at a regular interval in time has rhythm.  We therefore describe the resulting sound as being a "regular beat" or a "steady rhythm." 

2.1 Rhythmic Subdivisions

The standard "beat unit" in Western Music at this time is the quarter note.  The musical pulse (or "beat") is, in our culture, normally represented by the quarter note.

In Medieval times, the whole note (four counts) was thought of as the standard beat unit and quarters were thought of as being faster subdivisions of that unit (four times as fast).  Therefore it is easy for the beginner to get confused when dealing with the names of the subdivisions.  The following example will help:

Example 8: Hierarchy of note subdivisions

 

Given that the quarter note is assumed to be the standard, we typically "count" quarter notes as taking one pulse apiece, half notes last two, and whole notes last four. 

2.2 Flexibility of subdivisions and tempos

Remember that the same rhythm can be notated many ways.  The above chart designates the relative length of notes, but the Western system does not provide any absolute information.  Depending on the tempo of a musical idea, a whole note may be of some lengthy duration, or it may be very fast. 

To illustrate, examine the following rhythm, written with the quarter note as the beat unit.  Assume each quarter note is moving at a rate of 120 per minute (twice per second):

 

Now, compare that example with the following, which will generate the same rhythmic idea, only using different note values.  Let us now reckon each quarter note as moving half as fast as the above example, at 60 per minute (once per second):

 

When correctly executed, both of these examples will generate the same exact rhythm!  It is always helpful to remember how flexible the rhythmic notation system actually is.

2.3 Ties and Dotted Rhythms

A tie is used to designate an irregular duration.  For example, a note that lasts the space of three quarter notes does not exist; we only have half notes and quarter notes, no "third notes."  To make a sound last this long, we must tie together two pitches using a curved line, as seen below:

Example 9: Making a three-beat note with a tie

 

Remember that the tie is not to be confused with a slur, which is an articulation that calls for a smooth connection of different notes.  The tie is performed in a way that requires the performer to play a single pitch that has a duration equal to the values of the tied notes together.  The above example is three-quarters of a whole note (a half note plus a quarter note).

Another way to write the same exact thing would appear as thus:

Example 10: Making a three-beat note with two ties

 

Again, the duration of this sound will be three-quarters of a whole note.  Theoretically, there are an infinite variety of ways of doing this, as the following ridiculous example indicates:

 

The ties in this example call for a single pitch that lasts the duration of three beats, as the following math confirms:

 

2.4 Dots

A shorthand way of representing irregular note durations is to use the dot, which is added immediately after a pitch to indicate that it has been modified. 

The "rule of the dot" is that when a dot is added to a pitch, its duration is altered by lengthening it by half of its original value.  The following table shows several notes and how the dot affects their duration:

Example 10: How dots affect a note's duration

 

As you can see, dots and ties really do the same thingchange a note's duration.  Dots are often used because they are easier to read, and are very common in most scores. 

2.5 Measures and Time Signatures

Recall that rhythm is generated through repetition.  By repeating ideas through time we generate rhythm.  Rhythm can also be visual, as we will now see.

The example below is visually chaotic in that it has no regular "rhythm" (that is, no regular repetition takes place):

 

If we select a portion of this example, however

 

and then repeat that section, we will create a "visual rhythm:"

 

In the same way, musical patterns that are repeated create a regular type of rhythm.  We call this the measure.  A measure is nothing more than a pattern of music that is repeated regularly to create coherence. 

Although one could write a book on measures (and it has been done), we will simplify the discussion at this point to concentrate not on what a measure is but instead to reveal how measures are created.

To facilitate performance of a piece, composers will instruct the performer on how the measures within the composition are constructed by using a time signature.  A time signature conveys two critical pieces of information: the number of notes per measure and the type of note being used.  For example, this is a valid time signature:

 

This symbol tells the performer that musical information will appear in regular groups of four quarter notes.  Another (but equivalent) way to describe this information is to say that there are four quarter notes per measure. 

An alternative and more common way to convey this information is to express the "quarter note" quality of this time signature like this:

 

The "4" that replaced the quarter note is obtained by looking at the denominator for the fraction .  A grouping of seven half notes per measure would therefore look like this:

 

The "2" of course being derived from the denominator of the "half note," which is one-half, or .

2.5  Compound Meters

Humans, as we know, use hierarchy as a way of understanding the world.  We structure everything in our lives based on various decisions that ascribe a higher importance to one item than another, and systematically (whether we realize it or not) interpret incoming information based on some hierarchy.

Musical information is no exception.  Consider if you will, the following example:

Example 11: Rhythms with accents on every third note

 

If you clap this exercise, accenting every third note, you will begin to hear a larger beat pattern emerge, one that allows us to hear each individual clap as being subordinate to another.  The rhythm of this larger pattern is illustrated below, where we see the actual accented rhythm above creating this illusion:

Example 11: Generation of larger metric units through accents

 

The bottom staff represents the perceived structure taking place.  For practice, try clapping three-beat patterns, accenting the first beat.  Can you hear the effect taking place?

A similar effect happens with all music that has regular repetitions of three-note ideas, generating what is termed as "compound meter."  The example below shows several commonly used compound time signatures and rhythms in each.  Practice clapping or tapping these rhythms to obtain familiarity with this feature.

Example 12: Common compound time signatures

 

 

 

As you can see, compound meter can be somewhat complicated--just remember that compound rhythms are merely triplet divisions of the beat as opposed to duple divisions that we are so used to seeing and hearing!

© Copyright 2006 Thad Meyer and www.hammondjazz.com