- Hi.
In this video, I'm just going to show you
this particular resource
for making the calculation
of intervals easier.
And apart from any questions
you might have to face
on intervals, it might also help you
with things like transposition.
So, it works like this.
But basically, if we
start on the assumption
that an interval is
either perfect or major,
and if it's something else,
it kind of starts life as perfect or major
and goes from there.
You'll see the purpose
of what we're doing here.
So, you can download this as a PDF,
but let me just show you how to do it.
So, we have intervals that are perfect.
So, let's just stick that word here.
And the perfect intervals are the fourths,
the fifths,
and the octaves.
Okay, so, if a perfect interval becomes
a semitone bigger than perfect,
then it becomes augmented.
So, this is not a crescendo sign,
it's a mathematical sign,
lesser than, greater than.
And each one of these
is a semitone's worth.
All right?
So, if an interval is a semitone bigger,
in other words the notes
are a semitone further apart
than a perfect interval should be,
then it must be an augmented interval.
If, by the same token, a perfect interval
is actually no longer perfect
because it's a semitone
smaller than it should be,
then it becomes diminished.
So, it's quite useful, you see,
because if you know that the fourths,
the fifths, and the octaves
are the perfect intervals,
and you know that a perfect
interval is either perfect
or it gets changed to
augmented or diminished,
it stops you dealing with
calling things minor fifths
and things, because
there's no minor in sight
when you're dealing
with a perfect interval.
Okay, so, for example, C
to G is a perfect fifth
because C, D, E, F, G is a fifth.
You work in the major
scale of the lower note.
And the fifth note of C major is G.
Because G is the fifth note of C major,
that is a perfect fifth.
So, C up to G.
Perfect fifth, because G is
the fifth note of C major.
And this helps you to remember
that because it's a fifth,
it must be perfect.
So, anything that's a
fourth, a fifth or an octave
is a perfect interval.
Now, instead of it being
C up to G,
if it was C up to G-sharp,
you can see that I had C to
G, now I've got C to G-sharp.
It's now a semitone bigger.
My hands are now a semitone,
as it were, further apart.
So, the intervals got bigger.
The distance between the two notes.
So, if I go C to G-sharp,
it must be an augmented fifth.
If, however, I go C to G-flat,
then that's one semitone
smaller than a perfect fifth,
isn't it?
So, there's my perfect fifth, C to G.
C to G-flat, semitone smaller.
So that must be a diminished fifth.
Okay, so that's how the
perfect intervals work.
Now, the fourths, fifths,
and octaves are perfect.
Everything else is major.
So, as long as you can remember
four, five, eight, perfect.
Everything else is major.
Then this table works very nicely.
If you make a major
interval a semitone bigger,
just as before, it becomes augmented.
If you make a major
interval a semitone smaller,
this time, it becomes minor.
So, this is where the minors come in.
And if you make a minor
interval a semitone smaller,
then that's when it becomes diminished.
Okay.
So, that's how the table actually works.
So, if I've got, say, a third, C to E.
So, C, D, E, it's a third.
If E is the third note of C
major, this is a major third.
And it is.
So, that's why it's major
because it's not a fourth,
a fifth, or an octave.
So, it's not perfect.
So, it must be major.
So, seconds, thirds, sixths,
and sevenths will be major.
C to E, major third,
because E is the third note of C major.
But, if I made it C to E-sharp,
then it will become an augmented third
because it's got a semitone bigger.
If, instead of C to E,
it was C to E-flat, it's
got a semitone smaller,
so it's minor.
If it gets another semitone smaller
because it's C to E-double-flat,
then it's a diminished third.
So, that's the use of this interval chart
and it's why, great idea,
if you were to get into a theory exam,
you could very quickly
write out that chart.
Perfect, major.
Augmented, diminished.
Augmented, minor, diminished.
And then, when you're
calculating intervals,
you can just use that chart.
So, the few seconds that
it takes to write it down,
will be regained with extra bonus time
just for having that there
and helping you to
calculate what you're doing,
and making sure that you don't
muddle up perfect with major,
that you don't get minor involved up here.
It clarifies all that for you.
So, a very useful thing
to do at the beginning,
just to scribble that down
to sort out intervals.
