Making Your Own Tools:
Rhythm


We've talked a bit about scales and harmony. Those two elements alone are not enough to create music. We need a time frame on which to stretch the notes.

We create the scaffolding by using time signatures. Our ears tend to organize repeating sounds into groups of two or groups of three; for example, time signatures of 2/4 or 3/4. With groups of four, such as 4/4 time, we hear it as two groups of two. 5/4 time is heard as 2+3/4 or 3+2/4. Time signatures with the quarter note (or second) tend to be rather smooth. (I like using 5/4 for melodic passages because it can have a gentle flow to it.) Time signatures built on the eighth (or smaller) intervals can be more irregular. For example, the compound signatures of 6/8, 9/8, 12/8 group notes into units of three. In a measure of six eighth notes a 6/8 time signature indicates two groups of three, as opposed to the 3/4 measure of three groups of two notes. (If you are mixing both groupings, I suggest using both time signatures separated by a bar, to give the performer a heads up to expect groups of either two of three, or three of two.) Also, be wary of 9/8 and 12/8. Changing the expected groupings of three can lead to problems, as I learned the hard way several years ago. I used a 12/8 signature, but grouped the eighth notes into groups of 2, 3 ,4 and even 5. The performers were at a complete loss. When I rescored it, sticking with the traditional groups of three, they played the piece with ease—even though I had not changed a single note. Irregular signatures of 5/8 or 7/8 are usually read with no problem, as long as the beaming indicates the groupings, but more complex time signatures should be written as "composite" (3+3+2+2/8) or as "additive." (5/8+1/16)

Time Signatures

To add interest to a passage of music, we can do several things with time. We can vary the length of the notes. We can stress notes that are not on the beat. We can ties notes across the beat or measure line. We can add rests. We can break time units into more irregular divisions, like triplets, quadruplets, sextiplets, etc. We can change the time signature frequently. We can increase the beat-rate, or slow it down. We can do all these things are still get boring music. Why? Because it has to have structure. Without some basic organization to the rhythms we will tend to fall into meaningless randomness.

Random
Structured


Consider the two examples to the left. The first one is comprised of randomly-assigned note durations. It goes nowhere; no direction or elements to tie it together. The second example has some repeating rhythmic structures. Even though the time signature changes every measure, the figure of two eighths with a quarter note, indicated by the upper four brackets and the figure of eighth, dotted quarter, quarter, half note, indicted by the lower pair of brackets, tie the entire section together. The pitches and direction of the movements do not overcome the rhythmic patterns, which remain as unifying elements. Of course, you will quickly bore your listeners by repeating the same rhythmic patterns frequently. (After all, one Bolero was enough.) Patterns can be changed without altering their basic shape. A dotted 1/8th and 1/16th can be changed to a triplet composed of 1/4 plus 1/8, for example. A rest can replace a note in a figure and the basic structure will remain intact.

Another possibility is combining time signatures. As with polychords, we can have poly-rhythms. The most common would be a voice is 3/4 against another voice in 4/4. Without changing time signatures, we can accomplish the same thing with tuplets. For example, a measure in 3/4 can have a tuplet of 4:3. Using time shifts in this way can add considerable tension to a passage, or make the listener feel he has entered a time warp. Try something like this: in 4/4, start with a quarter rest, then fill the remaining three quarter notes with a 4:3 tuplet. Or, put a 4:3 tuplet inside a 3/4 measure. Here is a short excerpt for a work in progress, demonstrating the effect of instruments going "out of time" with each other. There is a regular rhythm established which is broken at the 13 second mark for two measures before returning to the more regular rhythm. (The section from the score shows those two measures and the two leading up to them.)

Time warp
Here's a musical treat demonstrating a simple rhythmic figure that ties an entire symphonic movement together. Arturo Toscanini conducting the NBC Symphony Orchestra at Carnegie Hall, in a telecast on March 22, 1952. I love the "B" theme of this movement; notice how it is still in the same time signature, but the rhythm is completely different than in the dominating figure.