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<u>'''Rhythm</u> ''' is a pattern of sound over time. This can be a single note sustained infinitely, a drum beat, dynamic accents in a melody, etc. The vast majority of compositions seek to establish some sense of order in rhythm. Thus, most songs are locked to a specific ''tempo'' and ''time signature''.
<u>'''Tempo</u> ''' establishes how many regular intervals of time (or <u>'''beats</u>''') should occur within a certain period of time, usually a minute. A common tempo is 120 beats per minute (bpm). This means there are 120 equal intervals of time per minute. Each beat will contain the standard minumum of controlled sound. For example, a drummer may play one stroke per beat, or a guitarist may strum a chord once per beat. Of course, doing the same thing every beat is boring. Master musicians know how to play "around" the beat, "off-beat", across several beats, or even subdivide a beat. But the point is that ''tempo provides a framework in time to create order'' - the listener does not feel lost, and a band or orchestra consisting of numerous instruments can simultize their playing to create a unified whole.
<u>'''Time signatures</u> ''' describe the number of beats per measure, where each <u>'''measure</u> ''' is basically a musical idea, although this is a very loose concept. The time signature consists of a pair of numbers with a slash dividing them. The top number is the number of beats per measure, and the bottom number defines what type of note corresponds to 1 beat. Most modern music is 4/4. That's 4 beats per measure with each beat represented by a quarter note. 13/8 would indicate 13 beats per measure with an eighth note lasting 1 beat. A guitarist may play each chord for one measure, strumming each beat. A drummer may play a repeating pattern every measure, with at least one stroke per beat.
<u>'''Harmony</u> ''' is the pattern of how frequencies interact. Most instruments are designed to sound distinct frequencies, called <u>'''pitches</u>''', which correspond to certain [[#Notes and Movement|<u>'''notes</u>''']]. '''Rather than deal with everything in absolute frequencies, note names are used to keep things from becoming complicated.''' Harmony is concerned mostly with the interaction of multiple notes - 2 or more notes combine to form a unique waveform, which we can perceive.
<u>'''Melody</u> ''' is very similar to harmony, but more concerned with sequences of single notes over time than with the combination of multiple notes. Again, it is very difficult to conceptualize harmony and melody as completely separate entities. Melodies are the lines to our favorite songs we sing - a melody can tend in a particular direction, finding resolution, and having its own rhythm (meter, accents). It doesn't require harmony, although harmony often gives it its context.
<u>'''Timbre</u> ''' is the quality of a particular sound. It is why a horn sounds like a horn and a violin a violin, even when playing the same notes. Musical instruments tend to focus on sounding particular frequencies, but not necessarily. For example, drums are not designed to focus as much on frequency as the general sound they create. Some instruments are noisier than others. Some can have a soft attack or even swell slowly louder until reaching full volume, while others might have a very noticeable, percussive attack. Some may sustain forever (synth). Some may decay immediately (sitar).
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The time signature often suggests a certain <u>'''meter</u>''', which is a repeating pattern of <u>'''accents</u>'''. Consider a common drum pattern in 4/4 - boom ssss taah ssss boom ssss taah ssss. The musical idea repeats every 4 beats, with accents on both the 1st and 3rd beats but the 3rd being a bit stronger (> - ^ -). ''(- is a normal hit, > is an accent, and ^ is a strong accent.)'' Here's a similar pattern in 3/4 - boom ssss taah boom ssss taah (> - ^). The musical idea repeats every 3 beats. We could play the first pattern in 3/4 or the 2nd in 4/4, but the pattern won't fit neatly inside each measure, appearing more complex than it actually is.
pattern 1
4/4 |> - ^ -|> - ^ -|> - ^ -| - same every measure
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''Note: popular instruments do not create a pure, single frequency, but a multitude of frequencies (and noise) when trying to sound a note. However the lowest frequency produced is called the fundamental frequency and usually the strongest. The additional frequencies are "overtones" of the fundamental frequency. This is discussed further in [[#Timbre|timbre]] below.''
When different notes are combined, they produce different waveforms. Two different notes played simultaneously is known as an <u>'''interval</u>'''. Three or more is known as a <u>'''chord</u>'''. Some intervals and chords are perceived as being more harmonic than others. This is driven by the ratio of the fundamental frequencies involved. We have already mentioned that a 4th interval is 4/3 higher than the base frequency. A 5th interval is 3/2 the base frequency. Basically, the simpler the ratio between the frequencies can be represented, the more harmonic the two notes are. The simplest ratio is an <u>'''octave</u> ''' - which contains 2x (2/1) the original pitch.
Because the octave is so harmonic, it is treated harmonically equivalent. Once the octave is reached, the note names repeat, and for harmonic purposes they are treated identically. In common Western music, there are only 12 possible notes in one octave. And most music only uses 7 of those notes in any particular musical idea. Such limited sets of notes are known as <u>'''scales</u>''', which drives the harmonic possibilities. This does not mean the composer/performer is strictly limited to those fundamental frequencies. It is simply used to provide an easily-understood framework to build upon, like tempo. Later we will explore why Western music uses the 12 tones per octave.
Harmony describes both the interactions of multiple simultaneous notes (chords) as well as the sequence of different chords, which is called a <u>'''chord progression</u>'''. Harmony often becomes synonymous with the chords that an accompaniment instrument plays, but it's important to realize this is only a part of harmony. The interaction of all the instruments, including those playing melody as well as accompaniment, is what truly forms harmony. But while melody is concerned with every note, harmony is only concerned with larger chord changes. While a melody may have quite a few different notes per measure, generally there is only one or two perceived chords per measure. We could consider harmony slower than melody, or at least requiring greater time for our minds to perceive it.
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Again, melody can get insanely complex...so what's our simple framework? Really, it's the same frameworks as harmony and rhythm. We take a subset of all possible frequencies and give them note names, and restrict them to 12 possibilities, with only 7 being "active" for a particular key or scale. Note duration is restricted to a common set, based around beats.
The big divergence from harmony is that pitch between octaves has signfigance. So, for example, if we take a common A minor ascending scale starting at A2 (110 HZ) as our melody; our last note should be A3 (220 HZ). Here is the example melody: A2, B2, C3, D3, E3, F3, G3, A3. This makes sure each note has an ascending pitch compared to the prior note's pitch. Similarly, A2, B3, C4, D5, E6, F7, G8, A9 is not the same melody, despite having all the same note names. It will sound much different to the listener. Ranges of notes grouped by pitch are called <u>'''registers</u>'''.
The melody stands out from the harmony by having louder volume or by being played in higher pitches. It typically has a less uniform or more complex rhythm than the rhythm accompaniment (consider a vocal melody compared to a drum beat).
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Some have more overtones than others. <u>'''Overtones</u> ''' are frequencies above the fundamental at an integer multiple of the fundamental (2x, 3x, 4x ...). Like harmony, the fundamental and overtones combine to make a distinct waveform; however, since the overtone frequencies are extremely harmonic, they are often perceived as a single pitch - the pitch of the fundamental frequency. Thus, we call these overtones part of the instrument's timbre, worrying only about the fundamental frequency for harmonic and melodic purposes.
Another topic for the composer is ''arrangement''. Arrangement describes applying some musical idea into a selection of instruments. Each instrument has a range of notes it is capable of playing, as well as their individual timbres. A composer desiring the use of a certain instrument for a certain part will compose that part within the range of the instrument. For example, if you were arranging a piece for flute, piano, and bass, you would likely have the flute play the melody, the piano playing chords, and the bass usually playing the root note of the chords. Naturally, melody is usually given a higher-pitch than the other instruments, and the root note of chords is usually played in the lowest-frequencies. We could come up with different arrangements that are harmonically equivalent; however, they would likely be less enjoyable to listen to.
=== Semi-tones and Whole-tones ===
In terms of melody, playing one tone then another is called <u>'''movement</u> ''' - it is as if the pitch moved rather than being two distinct, unrelated pitches. The proximity between two notes in the 12-tone scale is called the <u>'''distance</u> ''' between them. The distance between two consecutive notes is called a <u>'''semi-tone</u> ''' (also called a <u>'''half-tone</u> ''' or <u>'''half-step</u>'''). A <u>'''whole-tone</u> ''' (also called a <u>'''whole-step</u>''') is the distance of 2 semi-tones.
In general, the named notes are 1 whole-step in distance from each other. A is a whole-step from B, C is a whole-step from D, etc. '''The only two exceptions are B to C and E to F, which are defined as half-steps.''' This changes nothing about how they work - it just presents a simple naming convention for the keys of A Minor and C Major to avoid using [[#Sharps and Flats|sharps and flats]].
=== The Chromatic Scale ===
The <u>'''chromatic scale</u> ''' is the ordered set of the 12-tones:
{|class="wikitable"
=== Sharps and Flats ===
{{sharp}} or '#' means <u>'''sharp</u>'''. {{flat}} or 'b' means <u>'''flat</u>'''. These terms indicate the named note is raised or lowered one semi-tone, respectively. Looking back at the chromatic scale above, we now see that either a sharped version of the note below or the flatted version of the note above fills in the gaps between the notes without such symbols.
Multiple sharps and flats can be used. For example, A{{flat}}{{flat}} is 2 semi-tones below A. A{{flat}}{{flat}} corresponds to the same pitch as G. Similarly, G{{sharp}} is the same pitch as A{{flat}}, and B{{sharp}} is the same pitch as C. For our purposes, we are unlikely to deal with double (or more) sharps or flats. But it's important to understand what they are to remove some of the mystique from them.
==== Enharmonic Notes ====
Two notes are <u>'''enharmonic</u> ''' if they have the same pitch but are spelled differently. For example, B and C{{b}} are enharmonic, as are B{{s}} and C. As noted above, notes can have multiple sharp/flat symbols, which gives us a wide variety of enharmonic notes.
* C = D{{b}}{{b}} = E{{b}}{{b}}{{b}}{{b}} = G{{b}}{{b}}{{b}}{{b}}{{b}}{{b}}{{b}}
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A <u>'''scale</u> ''' is a set of notes, ordered from lowest to highest pitch, typically spanning one octave. This provides a framework for melodies, as well as harmony. The most common scales are the 7-note major and minor scales, which is why we refer to note that is 2x the pitch of another note as the ''oct''ave - it is the 8th note in the sequence. Scales often imply <u>'''tonality</u> ''' - melodies and harmonies seem attracted to a certain note in the scale (usually the first note), called the <u>'''tonic note</u>'''.
The chromatic scale featured above is a special scale - it features all 12 tones that most instruments are capable of sounding, and each note is the same distance from its neighboring notes. This means it has poor tonality - the relationship between any note and the others is the same for every note of the scale. No note sounds unique, with little or no attraction to any particular note.
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The ''major scale'' is composed of the following <u>'''whole/half step pattern</u>''': (w w h w w w h). So we start on the root note. We add +1 whole step to get the 2nd note, another +1 whole step for the 3rd note, +1 half step for the 4th, +1 whole step for 5th, +1 whole step for 6th, and +1 whole step for the 7th. Another +1 half step gets us to the octave of the root note (the octave is the 8th note in the common 7 note scales). Again, that's 2 whole steps, 1 half step, 3 whole steps, and another half step. Below is the chromatic scale starting on C, then the C Major scale. The h's represent half steps (semi-tones) and the w's represent whole steps. The chromatic scale consists of 12 semi-tones.
Chromatic |-h|-h|-h|-h|-h|-h|-h|-h|-h|-h|-h|-h|
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A <u>'''key</u> ''' is a scale assigned to certain notes. The key of C Major uses the note C as the first note of the major scale.
Notice how C Major has no sharp/flat notes. Again, this is just a naming convention to simplify things. C Major is usually the first key learned on any instrument. On a piano, it represents the white keys (no black keys). Some instruments are designed around C Major. Guitar, unlike piano, is very key-neutral. It is equally simple to play in C Major as any other key.