Does 5/8 = 5/4 = 5/2 ? The Definitive
Guide.
Not! First let me state that this is
in no way a definitive, nor even an authoritative statement on the
differences between 5/8 and 5/4, they are my interpenetration of the
differences and my use of them in my compositions.
On the surface one can say that they
are mathematically equivalent. By this we mean that by setting the
eight note in 5/8 time and the quarter note in 5/4 time to the same
BPM (metronome mark) both bars would move through time at the same
rate. Thus one could argue that they are equivalent and that there
no real difference between them. But ask your self this is a there a
difference between 6/8 and ¾ time? We can set their eight note BPM
to the same value, and both bars would move through time at the same
rate; but would they have the same feel? How about 6/8 and 6/4 ?
Part of the issue is how do we define
rhythm?
So what is the difference (from my
perspective)? It is one of “pulse”. In 5/4 time one would
“feel” five pulses in the bar, no matter the BPM. In 4/4 time
one feels four pulses in each bar. (I feel a lot of 4/4 music might
be better notated as 2/2, but that is another discussion.) In 5/4
there might be an emphasis on particular pulses (beats), but there
would be five even beats to the bar. In 4/4 there are 4/4 even pules
(beats) to the bar with perhaps (given the gene of music) bit more
emphasis on the first and third beats, or as some have explained; a
pattern of a Strong, Weak, Strong, Weak emphasis in the bar with the
third beat a little less strong than the first beat. In 5/4 time we
might have a pattern of Strong, Weak, Weak, (Less) Strong, Weak.
So let us go back and examine 6/8, ¾
and 2/4. In 6/8 and ¾ we have the same number of eight notes but
one is “felt” in two and one is felt in three. In 6/8 time one
has two even “pulses”, where the ¾ time has three pulses. [Yes
at extreme tempos, the ¾ could turn into more of a single pulse].
Are you familiar with Bernstein's “America” from West Side
story? It is in alternating 6/8 and ¾ bars. The “tempo” of the
eight notes remain constant, but the pulse, or beat, changes from one
bar to another. So what is the difference between 6/8 and 2/4?
They both are felt in two, but one has a base sub-division of three
eight note and one has a basic sub-division of two notes. But in both
the pulse remains constant.
Now onto 5/8 (and by extension 7/8,
9/8 divided asymmetrically, 11/8, 13/8, 14/8, et cetera). My
approach to 5/8 is that (when divided 3+2 or 2+3) it has TWO pulses
or beats per bar. But unlike 6/8 or 2/4 that also have two pulses
per bar, the two pulses in 5/8 are uneven in length; asymmetrical!
In a 3+2 division the first pulse of the bar would be 50 percent
longer than the second pulse. If you where to tap your toes to the
pulse in 5/8 the tapping would be asymmetrical, Does 5/8 = 5/4 = 5/2 ? The Definitive
Guide.
Not! First let me state that this is
in no way a definitive, nor even an authoritative statement on the
differences between 5/8 and 5/4, they are my interpenetration of the
differences and my use of them in my compositions.
On the surface one can say that they
are mathematically equivalent. By this we mean that by setting the
eight note in 5/8 time and the quarter note in 5/4 time to the same
BPM (metronome mark) both bars would move through time at the same
rate. Thus one could argue that they are equivalent and that there
no real difference between them. But ask your self this is a there a
difference between 6/8 and ¾ time? We can set their eight note BPM
to the same value, and both bars would move through time at the same
rate; but would they have the same feel? How about 6/8 and 6/4 ?
Part of the issue is how do we define
rhythm?
So what is the difference (from my
perspective)? It is one of “pulse”. In 5/4 time one would
“feel” five pulses in the bar, no matter the BPM. In 4/4 time
one feels four pulses in each bar. (I feel a lot of 4/4 music might
be better notated as 2/2, but that is another discussion.) In 5/4
there might be an emphasis on particular pulses (beats), but there
would be five even beats to the bar. In 4/4 there are 4/4 even pules
(beats) to the bar with perhaps (given the gene of music) bit more
emphasis on the first and third beats, or as some have explained; a
pattern of a Strong, Weak, Strong, Weak emphasis in the bar with the
third beat a little less strong than the first beat. In 5/4 time we
might have a pattern of Strong, Weak, Weak, (Less) Strong, Weak.
So let us go back and examine 6/8, ¾
and 2/4. In 6/8 and ¾ we have the same number of eight notes but
one is “felt” in two and one is felt in three. In 6/8 time one
has two even “pulses”, where the ¾ time has three pulses. [Yes
at extreme tempos, the ¾ could turn into more of a single pulse].
Are you familiar with Bernstein's “America” from West Side
story? It is in alternating 6/8 and ¾ bars. The “tempo” of the
eight notes remain constant, but the pulse, or beat, changes from one
bar to another. So what is the difference between 6/8 and 2/4?
They both are felt in two, but one has a base sub-division of three
eight note and one has a basic sub-division of two notes. But in both
the pulse remains constant.
Now onto 5/8 (and by extension 7/8,
9/8 divided asymmetrically, 11/8, 13/8, 14/8, et cetera). My
approach to 5/8 is that (when divided 3+2 or 2+3) it has TWO pulses
or beats per bar. But unlike 6/8 or 2/4 that also have two pulses
per bar, the two pulses in 5/8 are uneven in length; asymmetrical!
In a 3+2 division the first pulse of the bar would be 50 percent
longer than the second pulse. If you where to tap your toes to the
pulse in 5/8 the tapping would be asymmetrical, uneven, but not
random. The underlying eight note “rate” (temp) would remain
constant, but the pulse would fluctuate (in a precise manner). In
5/4 time the pulse would remain “constant”; id est two eight
notes for every beat/pulse. 10/8 time and 5/4 time that both had the
same BPM would be mathematically equivalent, but each would be felt
differently. In 10/8 time we would normally have four (un-even)
pulses to the bar (3+3+2+2 for example) where in 5/4 we would have
five even pulses (2+2+2+2+2). 7/8 time would have three pulses, 9/8
(divided 2+2+2+3) would have four pulses, 11/8 (3+3+3+2) would be
four pulses (Don Ellis once called it 3 and 2/3 time). Et cetra.
At extreme tempos these feelings of
pulse can break down or blur, and I am sure there are examples in the
literature that do not follow these guild-lines; as I stated this is
my working model on the use of 5/8 vs 5/4 in my music.
Questions?
Ursus Demens
