MUSIC MODULATION DEFINED
In music, a modulation is a key change.
It's often signaled by one or more melody
or harmony notes not in the current key
("accidentals"), found in the measure
before the new key.
There are several modulation formulas:
change of a half step, whole step, etc.
The purpose of a modulation is usually
to add variation to a song or tune, or
to change a mood, or to create tension,
or as a lead-in to a third key.
Multiple consecutive key changes can
be used to set a new harmonic chord
progression, (new chords, diads, triads,
etc.), or other functions.
GENE: Your modulation in half steps
(G-Ab-A-Bb) would serve as an
example of increasing tension.
At least, to my ears.
Try other key modulations, such as:
MAJOR KEY CHANGES:
(all major keys)
G(G scale)-D(D scale)-G-A-D-G;
or others, experiment.
There are many other modulation
formulae not listed here. Try the
listed chord progressions of a tune,
as a modulation formula. The chord
symbols are normally found above
the melody in a tune.
Best Regards, Modulations to You
JB