Transposition [Light] [Beginner] [Professional] [Notation] [Composition Light] [Composition Pro] [Drums and Percussion] [Guitar] [Choir] [Keyboard] [Soloist]
The idea is to modify a melody or a whole passage of a musical
work in order to play it higher or lower in the sound scale. In
the lesson on key signatures, we had listened to a melody
starting with C and then to the same melody starting with E. It
is an example of transposition. The melody was
transposed two notes higher.
It is frequent to use transposition when
composing a musical work. You can transpose a whole melody or
some notes. It is a current composition tool because you can
express several times the same thing while adding a change to it.
The simplest transposition is an octave change.
For example, all notes are played one octave higher. They keep
the same name. Open Ex027. The first two measures
contain a small melody which is transposed one octave higher in
the next two measures:

Listen to the sound difference. The second
melody is easily recognized as being the same one as the first,
but it is played higher.
Intervals [Light] [Beginner] [Professional] [Notation] [Composition Light] [Composition Pro] [Drums and Percussion] [Guitar] [Choir] [Keyboard] [Soloist]
To specify a transposition, intervals are defined. The example above is a transposition
of one octave, because there are 8 notes on the patch from
the original melody to the transposed melody (C, D, E, F, G,
A, B, C). Here are the names of intervals with the number of
notes contained in each:
Speaking about a third for example, one
counts the note names contained in the interval, without
taking into account the number of half tones. C and E form a
third, because there are three notes in the interval: C, D
and E. By counting the black and white keys, there are 4 half
tones:

Similarly, D and F form a third, but by
counting the half tones on the keyboard, there are only
three:

To qualify the exact content of an
interval, an adjective is added to it. They are specific for
each interval. Here is a table showing the interval names,
the adjectives qualifying them and the half tones contained
in them:
A minus sign "-"
shows that the adjective is not used for this interval. The
underlined numbers are the intervals separating the first
degree of a major scale from each other degree. They are
either major (as the scale) either perfect.
The interval separating C and E has 3 notes
and contains 4 half tones, it is thus a major third. The
interval separating D and F has 3 notes and contains 3 half
tones, it is thus a minor third.
You can precisely name an interval starting
from this table. What is the interval separating C sharp from
B flat ?
By counting the notes, C #, D, E, F, G, A,
B flat, it is a seventh. On the keyboard, you will count 9
half tones. According to the table, it is thus a diminished
seventh.
Diatonic and chromatic transposition [Light] [Beginner] [Professional] [Notation] [Composition Light] [Composition Pro] [Drums and Percussion] [Guitar] [Choir] [Keyboard] [Soloist]
Chromatic transposition respects the exact
number of half tones for each transposed note. The melody thus
keeps its original colour. Accidentals must sometimes be added to
notes so that the intervals of the melody remain the same.
To characterize a chromatic transposition, an
interval must be given with its content as well as the direction
of transposition (higher or lower). Open the Ex028 file.
It contains a small melody on 2 measures which is transposed a
major third higher in the next 2 measures:

Considering the first 2 notes of the melody (C
and E), they are separated by an interval of 4 half tones. By
going up a third, you obtain E and G but between these two notes
there is only 3 half tones. A sharp is placed in front of G to
correct the interval, adding the missing half tone.
Diatonic transposition only considers the
number of the interval notes and not its real content. To specify
it, the direction and the interval name are sufficient, no
capacity adjective is needed. Open the Ex029 file which
contains the same example as above, but transposed a third higher
in a diatonic way:

It is even simpler to do, because the intervals
do not need to be corrected. The two sharps were not added.
Listen to this example. In the last two measures, the melody has
a different colour. It is sadder and more resigned than the
first.
Diatonic transposition modifies the melody
colour. This aspect can be used to create for example a second
voice which will accompany the main melody. Open the Ex030 file
now and listen to the effect obtained. It gives you an example of
this same melody which is accompanied by a second voice
transposed a sixth higher in a diatonic way :

The diatonic transposition respects the
original tonality. This melody written in C major remains in C
major even when transposed, because no accidental is added. This
was not the case with the chromatic transposition example.