A beat is simply the rate a beat takes.
Why does this matter?
When we make changes to a musical sequence, we are changing the rate of the beat — at the same time the change in tempo can be seen as having a dramatic effect on our rhythm. The “speed” of the beat is one of the most important aspects in making music.
You can think of these things as “moments” in a musical sequence. If it’s a two-beat passage and the beat is 45-seconds, say, the first three beats of “Sally Simpson” would be 45, 45, 44 (or so). Now say you wanted to add four seconds to the tempo, say, 45-1.5, to equal a beat that was 4.1 seconds. Then you would need to replace all of the notes with fourteenth notes, fourfifths, fourseventh notes. Here we have four beats in one minute. That’s a lot of work.
We often refer to “a beat” more than one unit of time — but if the beat is so long, where do we start? In music theory, a beat is generally thought of as a unit of time, but we often talk about the duration of the beat as being a unit in our consciousness of time. We may know that the beat is a quarter of a second, but it’s hard to explain how two seconds make a quarter of a second unless we start each beat from beginning to end.
For example: If you have to play the first “Sally Simpson” chord at a 3/4 tempo, the “Sally Simpson” chord should start from the same starting point as the second “Sally Simpson” chord. In addition, the first “Sally Simpson” chord should end exactly where the second “Sally Simpson” chord begins (so the “Sally Simpson” chord should be the same length as the second “Sally Simpson.” This is usually referred to as “inertia.” You can think about the time it takes to play the first “Sally Simpson” chord as a measure of in-between time, and the time required to play the second “Sally Simpson” chord as an interval of time.
“One does not have to be a political scientist to see how easy it is to get people upset about things.” — Martin Wolf at The Financial Times
“One does not have to be a political scientist to see how easy it is to