Eli5: Music 8-12-16-32 Bars.


I attend a course on Music Appreciation at University. However, I do not possess a musical background.
I have read the book’s definition about the varying quantities of bars, but the explanation does not translate to what I’m hearing.

In: 0

To graphically understand this I suggest you search YouTube for a scrolling score of the Bach Inventions. The phrases or “musical ideas” are 4 bars long, followed by an “answer” 4 bars long.

This may be more abstract of an answer than what you are looking for. I do have a musical background so please feel free to ask as many questions as needed.

Multiple bars create musical phrases. When I was learning music as a child, phrases were explained to me as the sentences of music. If you think about it in terms of spoken and written language, sentences that are too short or too long sound and/or read funny, and it becomes difficult to translate thought from beginning to end. If it’s too long, the reader/listener forgets what they heard at the beginning. If it’s too short, there isn’t enough time to convey adequate information. Different amounts of bars in a phrase is one tool to convey different information musically. It’s a composition technique, just like how an author can convey different information through various sentence lengths.

Could you explain what exactly is giving you trouble? That may help us to pin down what we need to explain.

A “bar” is another word for a measure, which is a basic unit of rhythm measurement in music. Depending on the song, or even the measure in the song in some cases, the measure can be a different length. In the most common time signature in Western music, 4/4 time, a measure is 4 beats long, then the measure ends and another one begins. In 3/4 time, a measure is 3 beats long. You can have other time signatures but I don’t want to get things too complicated. For now, know that it’s a subdivision that helps musicians recognize where they are in a song.

Beats can be made up of sounds and/or silence. Beats can also be subdivided into portions of beats. Here is a very simple example: “twinkle twinkle little star.”

Twin-kle twin-kle / lit-tle star [ ] / how I won-der / what you are [ ]

1-2-3-4 / 1-2-3 [4] / 1-2-3-4 / 1-2-3 [4]

You can feel the beat on each syllable, so there are four beats per measure. But the second and fourth measures only have sound on the first three beats and the fourth beat is silent. This still counts as a beat though, so we have four full measures that are made up of both sound and silence.

So those are measures. But a song is about more than just measures. Musical ideas are expressed through “phrases” that are made of varying amounts of measures. These can be any length, but the numbers you gave in the title of the post are common ones that intuitively make sense to Westerners.

Listen to a well known piece of classical music and count out the measures if you can. This should be fairly easy since most older music doesn’t mess with the lengths of measures and tends to be pretty predictable. At the same time, listen for what sounds like the beginning and end of a thought or idea—like a sentence in spoken language, you should be able to tell when it starts and finishes. For an example from a well known song, let’s try Beethoven’s “Ode to Joy.” You probably know the tune already. Count out the measures—it’s 4 beats per measure, and there are about two beats per second. The main phrase is 16 measures long, then it ends. It’s repeated often throughout the song, and acts like a stanza of a poem. Even to the average untrained person, it should sound “complete” because the final measure sounds “conclusive.” It’s like putting a period at the end of a sentence to clearly mark where it ends. (There’s music theory behind how this works but that’s far beyond the scope of what you’re asking here.)

So that’s an example of a 16-bar musical phrase. But there are other lengths that are used. In old blues and jazz songs from the first half of the 20th century, there is 16-bar blues that uses the pattern I mentioned earlier, but just as common is 12-bar blues. It has a complete “sentence” that goes for 12 measures and then starts over. Other pieces might use other phrase lengths. It’s by no means standardized, but it generally sounds “natural” to use phrases that contain a number of measures that’s divisible by 4. I’m sure there are neurobiological reasons for why this works, but for now just know that it does generally work this way.

I hope that helps. Please let me know if anything didn’t make sense and I’ll try to explain further. Music is one of those weird things where most people understand it intuitively, but trying to explain it in detail can easily result in a lot of confusion.