Rhythm is how sounds are organized in time.
The concept of the Beat or the Pulse is the basic unit of rhythm, it is present whenever music is
organized in regularly occurring divisions of time. If you were to snap or clap or march to music, you’d
be doing so “to the beat.”
Tempo is the rate at which the beat occurs in a piece of music; the speed. Obviously, music can be very
fast [Taraf de Haidouks- Briu] or very slow [Gending Erhu]. Tempo is usually indicated in beats per
minute (BPM).
Music can also change speeds within a piece, slowing up or speeding up. Slowing down is known as a
decelerando [Gending Erhu, end of first big phrase, 1:00 or so], and speeding up is known as an
accelerando [System of a Down- Radio/Video, 2:17-3:35 or so]. Speed changes within a piece are often
used to make smooth transitions between sections of the piece that are at different speeds.
Music can also be nonpulsatile or quasi-pulsatile, meaning that it has rhythm, but no discernible beat
[Gyuto monks, Mongolian longsong, etc]
Meter is the organization of beats into structural levels of time- divisions or groupings of beats. Any
meter takes the specific number of beats and assigns strong and weak beats to create those structural
levels. Most music that we are familiar with in America is in some sort of Duple meter, meaning the
number of beats in the meter is a power of 2: 2,4,8,16 etc. Usually, in say, a meter of 4, the strong beats
are on 1 and 3 and the weak beats are on 2 and 4. Music that is in Triple meter, such as a Waltz, has the
beats in groups of 3, with the strong beat on 1, the weak beat on 2, and a possible secondary strong
beat on 3 [Tommy Emmanuel- The Diggers’ Waltz, 1:00 or so]. Groupings of 6 and 9 can also be Triple
meter under some circumstances.
Subdivision is dividing a beat into smaller/faster units. If you divide a beat into those powers of 2 again:
2,4,8,16 etc, then it is called a Simple subdivision. A Compound subdivision is when you divide a single
beat into 3 equal parts. [The Chieftains- Drowsy Maggie. The beginning is in a simple duple meter, while
something like 1:05 is in a compound triple meter, three beats each divided in three. 2:56 is in a
compound duple meter, 2 beats divided in groups of 3. The part of the piece that comes back several
times would DEFINITELY be an example of a Theme….].
Syncopation is a term for accented (louder) rhythms that are played on unstressed beats or unstressed
portions of the beat. If you think of the silly little thing for the cha-cha/conga line, da-da-da-da-da--DAH, that DAH is a syncopation, since it occurs BEFORE the beat you would expect it to occur on.
Syncopations can also occur after the beat. Many African-based and –derived musics are dependent
upon various levels of syncopation for their sonic identity [BataMbira- Butsu Mutandari/Iyesa].
There is also a whole mess of music that does not fit into the duple/triple-simple/compound formula.
This music is usually just classed under the huge umbrella of Multi-meter music. [Paul Brady- Out the
Door and Over the Wall].
Loudness- music can change volume, duh, gets louder, gets softer. In music, this is called Dynamics.
Getting louder is called a crescendo, getting softer is a decrescendo. In scientific terms, loudness is
called Amplitude and is measured in Decibels (dB). Amplitude is a measurement of the distance from 0
(silence) in both directions, positive and negative. So a soft A440 tone would have a low amplitude,
while a loud A440 would have a higher amplitude, greater distances from Zero. Same pitch/frequency,
different amplitude/volume/loudness.
There are several reasons why a piece of music might change volumes- the primary one is for contrast.
Contrasts in music highten the effectiveness of the expression, dramatic or otherwise, and can also
highlight structural differences between different sections of music. This can be done not only through
individual players playing louder/softer, but also through texture and orchestration (adding/taking away
how many and what kinds of instruments are playing, more on that later).