Lesson 12: 音程 (Intervals), Part 2

This lesson will cover more advanced topics in "intervals".

Enharmonic (異符同音) intervals

It is important to note that the interval number is determined by how the two notes are spelled. E.g. the interval between D and F# is major 3rd, but the interval between D and Gb is diminished 4th. Even though F# and Gb are the same note on the keyboard, because they are spelt differently, they need to be written differently (F is a 3rd and G is a 4th in D major). This applies not only to the upper note, but to the root as well. E.g. the interval between F# and C is diminished 5th, but the interval between Gb and C is augmented 4th.

Inversion of intervals

To invert an interval, simply raise the lower note by one octave. That will bring it above the upper note, and making the upper note the root note. After the notes are inverted, the interval between the new root note and upper note can be determined the way described before.

There is also a shortcut to determine the inverted interval. The interval number of the inverted interval is always equal to 9 minus the original interval number. What about the quality of interval? Here is the rule for inverting intervals (try to verify it yourself!):

Major becomes minor, and vice versa
Augmented becomes diminished, and vice versa
Perfect stays perfect

E.g. the interval from C to A is major 6th, so the interval number of the inverted interval (from A to C) is 9 – 6 = 3. And using the rule above, the inverted interval should be a minor interval. Therefore, the interval from A to C should be minor 3rd.

Compound interval

Up to this point, we have only considered intervals that are not more than an octave. In reality, intervals can go beyond an octave. To determine any interval that is greater than an octave, simply follow the following steps:

1. raise the root note by one octave (or lower the upper note by one octave), so that the notes are now less than an octave apart
2. determine the interval between the notes as described previously
3. add 7 to the interval number to get the actual interval

E.g. to determine the interval between C and high E, we first determine the interval from C to E, which is major 3rd. So, the actual interval is major 10th after we add 7 to the interval number.

Lesson 11: 音程 (Intervals), Part 1

The term "intervals" (音程) refers to the distance between two notes. It can also be considered as the difference in pitches (or frequency) between two notes. The concept of intervals is very important, because they are the building blocks of chords.

There are two types of intervals in music: melodic interval and harmonic interval. Melodic interval is the interval between two notes when they are played one after another. Harmonic interval is the interval between two notes when they are played simultaneously (e.g. in a chord). In both cases, the lower-pitched note is called the “root”, and the interval is always defined as the interval from the root to the upper note.

Melodic interval:

Harmonic Interval:

Calculating intervals

To determine the interval between two notes, you always start from the root and count the number of steps to the upper note. Consider the root as the “doh” of the scale, and determine which note in the scale the upper note is. E.g. to determine the interval between F and A, we start with F as the “doh” of the scale (i.e. F major), then A is “mi” (the 3rd note) in F major.

The interval number is the number of degree of the upper note in the key of the root. So, in the previous example, A is a 3rd above F, or you can say that F and A are a 3rd apart. (doh = unison, re = 2nd, mi = 3rd, fa = 4th, so = 5th, la = 6th, ti = 7th, doh’ = 8th/octave)

But the interval number alone is not sufficient to describe an interval. We need to specify the quality (型態) of interval between F and A (quality of interval). If the upper note is actually IN the major scale of the key of the root, then the interval is either perfect (純音程) (unison, 4th, 5th, octave) or major (大音程) (2nd, 3rd, 6th, 7th). Let’s look at the example again. Since A is in the scale of F major, and it is the 3rd note of the scale, so the interval from F to A is major 3rd.

For a note that is NOT in the major scale of the key of the root, you can determine the quality of interval by counting how many semitone (or half step) it is above or below the note that is in the scale. Here are the qualities of interval that are not major nor perfect:
- augmented (增音程): one semitone larger than a major/perfect interval
- minor (小音程): one semitone smaller than a major interval
- diminished (減音程): two semitones smaller than a major interval, or one semitone smaller than a perfect/minor interval.

Can you tell the intervals between the following pairs of notes? (leave your answers in the comments)
- F and Ab
- F and A#
- F and Abb

In summary, just remember that unison, fourth, fifth, and octave can be (from low to high pitch) diminished, perfect, augmented; whereas second, third, sixth, and seventh can be diminished, minor, major, augmented.

Lesson 10: 三連音(Triplets)

In addition to the different note values introduced in Lesson 5 and Lesson 6, there is a special class of notes that occurs frequently in both classical music and contemporary music, called the triplets (三連音). As the name suggests, it is used when you want to divide a duration into 3 equal subdivisions in any simple time signature.

Triplets are used whenever you want to divide any duration into 3 equal parts in a simple time signature, because in any simple time signature, the beats can only be divided into 2, 4,... equal subdivisions (power of 2, basically).

In a simple time signature, usually two quarter notes equal to one half note; and three triplet quarter notes equal to one half note (two normal quarter notes). Similarly, three triplet eighth notes would be equal to one quarter note (i.e. two normal eighth notes). Triplets are usually written with a number '3' above or below the notes. Sometimes, you will see a square bracket or a slur across the triplet, and sometimes only the number is seen. Rests and dotted notes can be used as needed in triplets. This is one of the common ways to write triplets:


Triplets can also be considered the building blocks of compound time signatures, because all beats in compound time signatures are divided into 3 equal subdivisions. E.g. in the common time signature (4/4), if all four beats are written as triplets, it will be equivalent to the compound key signature 12/8. Since all beats in compound time signature are triplets, they will not be labeled as triplets, and therefore, a beat in a compound time signature is a dotted quarter note, instead of a quarter note.

Optional:
There may be circumstances where we want to divide one beat (a dotted note) in a compound time signature into 2 equal subdivisions. To achieve that, a duplet is used. Two duplet eighth notes equal one dotted quarter note (i.e. 3 compound eighth notes). Theoretically, one beat can be divided into n equal subdivisions, by the use of tuplets (the general term for notes like duplets and triplets).

Lesson 9: 拍號 (Time Signatures)

Time signatures typically consist of 2 numbers like in a fraction. It is always written after the key signature at the beginning of a piece, and will not be written again unless the time signature changes halfway in the piece (see Lesson 8). There are 3 types of time signatures: simple, compound, and complex. Each type of time signatures will be disccused below.

The two numbers in a simple time signature tell you the following information:

• Top number: how many beats there are in a bar/measure.
• Bottom number: what the value of one beat is, or the beat value.

E.g. Consider the time signature . The bottom number is 4, which means that each beat is a quarter note; the top number is 2, which means that there are 2 quarter notes in each measure. Similarly, the time signature means that there are 3 beats in each measure, and each beat is an eighth note. An important concept in simple time signature is that each beat can be divided into two subdivisions.



The most commonly used simple time signature is . Because it is so commonly used, it is sometimes written as 'C', which denotes 'the common time'.

In the second type of time signatures: compound time signatures, the numbers are read a little differently.

• Top number: how many subdivisions there are in a bar/measure.
• Bottom number: what the value/duration of one subdivision is.

So what is 'one beat' in a compound time signature? In compound time signatures, each beat is divided into three subdivisions (instead of 2 in simple time signatures). In other words, 'one beat' would be 3 times of a subdivided note in a compound time signature. This also implies that in all compound time signatures, the top number should be divisible by 3 (except for cases like 3/4 or 3/8, because technically it is pointless to have only 1 beat per measure). This is how you can distinguish between simple and compound time signatures.

E.g. The time signature means that each subdivision is an eighth note (bottom number), and there are 6 subdivisions in each measure, meaning there are 6/3 = 2 beats per measure. One beat in this time signature would be a dotted quarter note, because it is 3 times of an eighth note. Similarly, the time signature means there are now 9 subdivisions per measure, which means there are 9/3 = 3 beats per measure. Note that in all compound time signatures, 'a beat' will always be a dotted note.

The third type of time signatures, complex time signatures, are a lot less encountered than simple and compound time signatures. It typically involves a prime number (other than 2 and 3) on the top. E.g. 5/4 or 7/4. In these complex time signatures, a measure can be interpreted differently according to the composer. E.g. for the case of 5/4, the 5 beats can be played as 3+2 or 2+3, and in the case of 7/4, a measure can be divided into 4+3 or 2+3+2, etc.

Things to learn in this lesson:

1. What do the numbers in a time signature stand for?
2. Be able to differentiate between simple, compound, and complex time signatures.
3. What are the differences between simple and compound time signatures?

Lesson 8: 如何讀譜 (Reading piano scores)

The few most important things that you will need to pay attention to when playing songs/pieces are those illustrated in the following diagram:

• Clefs: Most worship songs that you will encounter will have treble clef on top and bass clef at the bottom. However, in classical music, it is not uncommon to have either all treble clefs or all bass clefs for both hands, so it is always good to check.
• Key signature: This tells you what key the song is in. The key signature is shown on all the staffs throughout the piece. The key of a song can change in the middle of it, so it is important to pay attention to such changes.
• Time signature: This tells you how many beats are there in each measure (or bar). However, this is completely unrelated to the tempo (speed) of the piece. A more extensive explanation on how to read time signature will be covered in later lessons.
• Bar lines: A bar line is drawn to separate measures. E.g. each bar has 4 beats in a given song, then a bar line will be drawn every 4 beats.

In addition to the components mentioned above, there are also other components that define the song/piece. For example,

• the tempo of the piece is typically written at the beginning of a piece, above the 1st line.
• the dynamics (relative loudness) of the piece can be written anywhere in the piece and changes as the piece goes.
• there are also a wide variation of words used in music to mark the mood in the piece.

Lesson 7: 調號 (Key Signatures)

In Lesson 4, we learnt that the black keys can be represented on the staff using sharps (#) or flats (b). And the reason for having sharps and flats is that white keys alone cannot be used to represent all the scales in different keys.

So, how many different keys are there in total? By looking at the keyboard again, we see that there are 7 white keys and 5 black keys in each octave. Therefore, there are 7+5=12 different keys in total. Each of these keys are named by the note it starts with. E.g. the key that starts with C is called C Major.

Each major (大調) key has a unique key signature (調號), with a unique number of sharps or flat. By "unique", it means that e.g. A major's key signature has 3 sharps, so whenever you see 3 sharps, it must be A major and nothing else. This will be slightly different when we learn about the minors (小調), but let's not worry about them yet.

In order to tell how many sharps/flats each of the 12 keys have, we have to construct their scales.

• Starting with C major (C大調), which has no sharp nor flat. To construct the next scale, we go to the 5th note in the scale of C major: G.
• The key that starts with G is G major (G大調), and you will find that it will have one sharp (F#) if you construct its scale using the pattern shown in Lesson 4.
• To construct the next scale, we, again, go to the 5th note of the scale of G major: D.
• Repeat this process and you will find that all 12 keys will be constructed. (It is easier to do this exercise at a keyboard/piano.) Some of them will have sharps in their key signatures, and some will have flats.

The process of constructing scales can be summarized by the Circle of Fifths (調的五度循環):

The logic behind the Circle of fifths is that when you go clockwise, the next key is always a perfect 5th from the current key. This is the more technical way of saying that the next key always starts on the 5th note of the current key. Note that the keys on the right of the Circle of fifths are the keys with sharps in their key signatures, and the ones on the left are those with flats in their key signatures. As you may notice that F# (or Gb) major is at the bottom of the circle, because its key signature can be either 6 sharps or 6 flats. This is the theory behind differnt keys, but the most important thing is to remember ALL the key signatures, which are summarized below:

Questions that you should be able to answer by the end of this lesson:

1. Can you name the associated major key by looking at the key signatures?
2. Can you write the key signatures for any given majore key?
3. Can you remember how many sharps or flats each of the major key has?

Lesson 6: 音符時值...續集 (Note duration, cont'd)

Having just the whole note, half note, quarter note, eighth note, etc. are not sufficient for expressing more complicated rhythm in most classical or contemporary music. E.g. how do you write 3 beats? There must be a way in music to do that. In fact, there is more than a way!

Dotted Notes

When you add a dot to a note, you add half of its value to the note. E.g. a quarter note is normally 1 beat, so a dotted quarter note would last 1.5 beats. Similarly, a half note is typically 2 beats, adding a dot to it (dotted half note) would make it 2 + 2/2 = 3 beats!

Tie

A tie can occur between two or more notes to add all their values together. E.g. when a quarter note is tied to a half note, then the result would be 2 + 1 = 3 beats. When a quarter note is tied to a sixteenth note, the result would be 1.25 beats. The tie is also used when a note is being stretched across measures.

There are also times in music when nothing is to be played. These periods of silence need to be properly notated as well, thus the need for another class of symbols: rests (休止符).

Just like the notes shown in Lesson 5, there are whole rest, half rest, quarter rest, etc... the duration of which corresponds to their respective notes.

Whole rest

Half rest

Quarter rest

Eighth rest

Sixteenth rest

Rests are also similar to notes in the way that both rests and notes can be dotted. E.g. a dotted quarter rest stands for a rest of 1.5 beats. However, ties cannot be used on rests.

Questions for this lesson:

1. Do you know how to write all the notes/rests presented in this lesson?
2. Can you name all the different notes/rests at sight?
3. Can you calculate the total duration of a string of notes/rests?