Music is a universal impulse of mankind. Every society around the globe has its own musical tradition, and while the terminology is different, all global musical makes use of beat and rhythm. But what do these two important terms mean and what is the difference between beat and rhythm?At its simplest definition, beat is tempo, pace, or the time it takes to play a piece. In Western music, beat is often demarcated by a metronome, device that produces a steady pulse at the rate of x per minute. So a metronome marking of 60 would have 60 pulses per minute, or one per second, while a marking of 120 would have 120 pulses per minute, or two per second. Throughout the entire piece the metronome would mark out the same pace of the beat, regardless of what the other instruments were doing rhythmically around it. The beat is often set by the composer at the beginning of the piece, either with a metronome marking, or with an Italian term that stands for a range of metronome markings. Beat is also defined by the time signature, two numbers stacked on top of each other at the beginning of the first line of music. The top note tells the number of beats in a measure and the bottom note the type of note to get one beat. Therefore, a piece that is marked allegro 4/4 means that the piece should have between 120 and 168 beats per minute and a quarter note gets one beat. This piece would have a fast beat.
Rhythm can be confused with beat, because sometimes the beat is also the rhythm. For instance, in a piece with a 4/4 time signature a section of only quarter notes would be both the beat and the rhythm. However, while beat must be constant, rhythm is, by definition, variable. Rhythm is the length and accent given to a series of notes in a piece. In most Western music, rhythm and pitch go hand in hand to create a melody. The rhythm determines the length of the notes and the pitch whether they go up or down. A noted exception is plain chant, in which the singer concentrates solely on the pitch and allows the lyrics to move the melody along without rhythm. Beside the length of notes, rhythm is also created when some notes are emphasized over others. Standard Western music puts the emphasis on the first note of a measure, but putting the emphasis on the second and fourth, or back beats, can create a new type of rhythm.
While beat and rhythm are inexorably linked to create Western music, beat is the unchanging tempo of the piece and rhythm is the pattern in which the notes of the piece move.