**THIS ARTICLE IS UNDER SOME SERIOUS CONSTRUCTION! A lot of the time, you'll hear people that claim music theory is not important, or maybe even that it stifles creativity. Often cited are case examples such as Paul McCartney's inability to read sheet music. While it is absolutely true that music theory is not required to write great music, for some people, it can help greatly, and introduce new ways to express oneself through music. Music theory is a set of concepts and a language you can use to communicate ideas about music with other people. The main benefits of learning about music theory are that you will be able to express musical ideas in a concise and accurate manner and be able to think about music in a structured way. '[t[4]I. The Notes and Keeping Time'[/t] A '[b]pitch'[/b] is a specific frequency of sound. This frequency may be expressed in '[b]Hertz'[/b] (Hz), a unit that measures cycles per second--in this case, oscillations per second of a pressure wave. Because of way the human ear and mind perceive sound, a pitch with a frequency that is an integer multiple of another pitch's frequency will sound very similar to it--for example, 440 Hz and 880 Hz. The pitches are clearly distinguishable, but seem to share a certain quality. Because of this effect, music has the concept of a '[b]pitch class'[/b]: a set of pitches with the same name that are considered more or less equivalent for the purposes of harmony (for example, "C"). In music, the most common way to refer to a pitch is by a combination of its pitch class and octave, such as "A4", a pitch of 440 Hz in modern tuning. The pitch classes are as follows: A, A♯, B, C, C♯, D, D♯, E, F, F♯, G, G♯ '[t[2]Note Value'[/t] The '[b]value'[/b] of a note is an expression of how much time it occupies. A '[b]quarter note'[/b] is a quarter of a common time measure (see below). As an example, a 7/4 measure can hold seven quarter notes, while a 2/4 only two. An '[b]eighth note'[/b] simply takes up half the time of a quarter note. A '[b]half note'[/b] is twice the length of a quarter note. A '[b]whole note'[/b] takes up an entire common time measure. In sheet music, adding a single dot after a note increases its duration by half; thus, a '[b]dotted quarter note'[/b] means a note with a length or '[b]value'[/b] of a quarter note plus an eighth note. '[t[2]Time Signatures'[/t] A '[b]measure'[/b] is a unit in music which defines the length of an arbitrary phrase, sort of like a coherent musical statement. Measures are subdivided into equal time intervals called '[b]beats'[/b]. A '[b]time signature'[/b] is the way to express the number of beats in a measure. The time signature most often used in Western popular music is 4/4, also called '[b]common time'[/b]. The top number in a time signature tells how many beats are in a measure, and the bottom tells what note value makes up a single beat (ordinary a quarter, eighth, or sixteenth note). A time signature is '[o]NOT'[/o] a fraction--3/4 are 6/8 denote two different meters (by convention, 3/4 denotes a measure split into 3 quarter-note pulses, and 6/8 denotes a measure split into 2 dotted-quarter-note pulses). '[t[4]II. Intervals and The Ionian (Major) and Aeolian (Minor) Modes'[/t] Now that we have our 12 notes, we have to figure out how they work relative to each other. A way of looking at relative pitch is examining '[b]consonance'[/b] and '[b]dissonance'[/b], which are respectively defined as when notes, when played simultaneously, either work 'well' together, or 'clash' with each other. As a rule of thumb, the closer notes are together, the more they clash, until the difference becomes null to our brain. Notes that are one or two semitones apart are generally said to be dissonant. This has to do with frequency intervals and ratios (see Section VI). The intervals relative to a base (or '[b]tonic'[/b]) are displayed below. Those '[o]italicized'[/o] are relatively important! 0 semitone difference = unison (the same note) 1 semitone difference = '[o]minor second'[/o] 2 semitone difference = '[o]major second'[/o] 3 semitone difference = '[o]minor third'[/o] 4 semitone difference = '[o]major third'[/o] 5 semitone difference = '[o]perfect fourth'[/o] 6 semitone difference = augmented fourth 7 semitone difference = '[o]perfect fifth'[/o] 8 semitone difference = minor sixth 9 semitone difference = major sixth 10 semitone difference = minor seventh 11 semitone difference = major seventh 12 semitone difference = '[o]octave'[/o] This is rather confusing at first glance. However, there seem to be recognizable patterns. For example, a minoris always closer to the tonic than a major . The perfect intervals are the most consonant intervals, other than the octave! '[t[4]III. Chord Theory'[/t] Now that we've learned the two most widely-used scales, we can assign '[b]chords'[/b] to them. A chord is three or more notes played either simultaneously, or sequentially. A chord played sequentially is called a '[b]broken chord'[/b] or an '[b]appergio'[/b]. A chord consisting of a scale's note, that note's minor/major third, and its perfect fifth (usually, at least, the fifth can be flatted or sharpened) is known as a '[b]triad.'[/b] In '[b]Roman relative chord notation'[/b], all chords are represented by a Roman numeral. The '[b]major chords'[/b] (which use a major third) are represented by capitalized numerals, while '[b]minor chords'[/b] (which use the minor third) and '[/b]diminished chords'[/b] (which uses a minor third and flats the fifth to an augmented fourth) are represented by a lowercase, with the diminished chords differentiated with a small circle next to the numeral. In a major scale, the '[b]tonic chord'[/b] is represented by a Roman numeral I. The chords are named as follows: I = tonic II = supertonic III = mediant IV = subdominant V = dominant VI = submediant VII = leading We will get into how each chord is used shortly. The major scale has the following chords: I ii iii IV V vi vii° The minor scale has the following chords: i ii° III iv v VI VII As you can see, both of these (and all other modes of the diatonic scale) have three major chords, three minor chords, and a single diminished chord. The order is even the same! The only difference is which chords take prevalence in the mode. This leads us to one of my favorite revelations in all of music theory. A '[b]relative key'[/b] is a key that has the same notes and chords as another key, but the parallel key is just shifted to become major or minor! Case example: C major consists of C, D, E, F, G, A, and B. Therefore, its chords are: I - C ii - Dm iii - Em IV - F V - G vi - Am vii° - B° Now, shifted forward so that vi becomes i, we get A minor! i = Am ii° = B° III = C iv = Dm v = Em VI = F VII = G It's almost magic to me! And you can do this with any mode, even into modes that are not major or minor! (See Section V) A '[b]parallel key'[/b] is a key that has the same root note as another key, but has different notes, and therefore, different chords! C major and C minor are parallel keys! '[t[2]Chord Progressions and Cadences'[/t] '[t[2]Seventh and Extended Chords'[/t] A '[b]seventh chord'[/b] is a triad that has had a seventh tacked on to it. There are three main types of seventh chords: A '[b]dominant seventh chord'[/b] adds the minor seventh of the key to a major triad. A '[b]minor seventh chord'[/b] adds the minor seventh to a minor triad. A '[b]major seventh chord'[/b] adds the major seventh to a major triad. There are also lesser-used seventh chords. '[t[2]Other Chords of Note'[/t] '[t[2]Borrowed Chords and Harmonic Dissonance'[/t] You don't just have to use the triads provided to you by a key! A '[b]borrowed chord'[/b] is a chord that is not in the key, but is instead borrowed from another, usually closely-related key. A '[b]related key'[/b] is a key that shares many similar chords to another key. For example, in A major, C and G are not chords in that key! Borrowed chords are represented one of two ways: With a flatted Roman numeral (such as ♭III, which means it is a semitone lower than the III chord) Or with a slash, representing which key the chord was taken from! (such as IV/V, which means you have taken the IV chord from the key in which the V chord is the I chord) Dissonance can be used in a number of ways in harmony, such as creating emotions of suspense, dread, or horror, or simply as a transition to a more consonant chord. '[t[4]IV. Melody'[/t] Take a note. I will take C, and name it Do in '[b]solfege'[/b] notation. Let's also give it the number it corresponds with in its major mode. With this information, we can conclude we are working in C Major. Do = 1 = C Re = 2 = D Mi = 3 = E Fa = 4 = F Sol = 5 = G La = 6 = A Ti = 7 = B '[t[4]V. Uncommon Modes'[/t] We know by now two scales! You may have been wondering that if we can shift the major scale a certain amount to become the minor scale, can't we shift it different amounts to become different scales? And indeed, we can! These other modes are listed below, by the chord from the major scale that becomes I. ii - Dorian iii - Phrygian IV - Lydian V - Mixolydian vii° - Locrian These modes are not as commonly used as their major/minor counterparts, but are more common than one may think, and are often confused by novices for major/minor in various pieces. In other styles of music such as jazz, modern classical, and traditional music from other cultures, other scales may be used in addition to or in place of the diatonic scale. One common example is the '[b]harmonic minor scale'[/b], equivalent to a minor scale with a major seventh instead of a minor seventh. By changing the root of this scale, we can create new modes such as '[b]Phrygian dominant'[/b] (equivalent to the diatonic Phrygian mode with a major third). '[t[4]VI. The Science of Sound'[/t] '[t[4]VII. Timbre and Sound Design'[/t] '[t[4]VIII. Miscellaneous Tips and Tricks'[/t] '[t[4]IX. Helpful External Links and References'[/t] http://www.youtube.com/watch?v=i_0DXxNeaQ0 http://hooktheory.net http://musictheory.net
