Difference between revisions of "Rock"

Revision as of 16:31, 28 April 2014

Rock and Roll quickly became the dominant style of music in the late 20th century. This page lists many of its aspects.

Arrangements

A large part of the rock style emerges from its arrangements. Generally, rock features a drummer, a bass player, a guitarist, and a vocalist. Many artists incorporate far more instruments, often to pull-in influence from other styles. For example, some artists will use string sections in ballads, world percussion for a primitive or latin feel, or samplers/synths for an electronica feel.

Often, the guitar is distorted, allowing it to cover a wider range of frequencies at the expense of note clarity. This also reduces the guitar's dynamic range.

Usually dynamics are eschewed altogether, using compression on the vocals, guitars, and bass to provide a consistent "loudness" to the music. The drums are used to emphasize accents and can also perform occasional build-ups by using dynamics; however, they often use different parts of the kit for accents rather than simply altered dynamics.

Drums are used much differently in rock than classical music. Rather than being used exclusively for dynamic build-ups or strong accents, the drums play on almost every beat. They serve as a time-keeper, sometimes doing so directly by riding the hi-hat or ride cymbals; other times through a repetitive pattern or groove. The bass drum, snare, and crash cymbal are often used for accents, while the toms, hi-hat, and ride cymbal are used to keep time or embellish a groove.

Vocals are usually contained within a single octave or even smaller range of notes, with a focus on simple melodies that most people can easily sing. A wide timbre of vocals is emphasized, with some styles featuring screaming, processor-based distortion, or even pitchless singing (rap, spoken word).

Harmony

Rock tends to avoid strong cadences (V - I) and complex harmonies (long progressions, 4+ note chords). Dominant 7th chords are somewhat rare, but are the most common 4+ note chord seen. Suspended chords actually appear somewhat frequently; however, they are usually used in and of themselves rather than as a means to prolong a harmonic resolution. Augmented and diminished chords almost never appear.

Rather than use complex progressions, rock focuses typically focuses on riff-based grooves or shuffles (that have a static harmonic fingerprint) or repeating 3 or 4 chord progressions.

Riffs

Rock guitar playing often employs riffs instead of chords. A riff is a repeating phrase, composed mostly of single notes or simple intervals. A riff may imply a tonality or a harmony given the notes it uses.

Movement in Parallel Fifths

In classical composition, voice leading avoided moving two voices in parallel 5ths, which could feel more melodic as though the pitches were more important than the harmonies. Rock embraces parallel fifths. It tends to use simpler harmonies and less voices in general. Thus it uses movement in parallel fifths to emphasize harmonic changes.

Power Chords

Rock tends to use distorted guitar, which introduces lots of overtones above the fundamental pitch along the harmonic series, which adds in an ascending order octave, 5th, octave, major 3rd, 5th, minor 7th, and more. This means complex chords can sound quite noisy and dissonant, as not only will the fundamentals have some dissonance but also all their overtones. Even a simple minor chord can sound a bit too much for some people. Rock tends to use power chords instead.

Power chords aren't actually even chords - they consist only of root and 5th; they are intervals. Typically, power chords are voiced root - 5th or root - 5th - octave. Rarely, you will see them as the 4-string root - 5th - octave - 5th or the inverted 5th - root.

    1  2  3  4  5
g---------7-----12--
d------5--5--5--12--
a---5--5--5--5--10--
e---3--3--3-----10--

1. 2 string
2. 3 string
3. 4 string (2 octave)
4. inverted
5. inverted 4 string (2 octave)

|-|-|-|-|     |-|-|-|-|     |-|-|-|-|     |-|-|-|-|     |-|-|-|-|-|     |-|-|-|-|     |-|-|-|-|  
|-|-|-|-|     |-|-|-|-|     |-|-|-|-|     |-|-|-|-|     |-|-|-|-|-|     |-|-|-|-|     |-|-|-|-|  
|-|-|-|-|     |-|-|-|-|     |-|-|-|-|     |-|-|-|-|     |-|-|-|-|p| 5   |-|-|-|-|     |-|-|p|-| R
|-|-|-|-|     |-|-|-|-|     |-|-|p|-| R   |-|-|p|-| R   |-|-|r|-|-| R   |*|-|-|-| R   |-|-|r|-| 5
|-|-|p|-| 5   |-|-|r|-| 5   |-|-|p|-| 5   |-|-|r|-| 5   |-|-|m|-|-| 5   |*|-|-|-| 5   |i|-|-|-| R
|i|-|-|-| R   |i|-|-|-| R   |i|-|-|-| R   |i|-|-|-| R   |i|-|-|-|-| R   |-|-|-|-|     |i|-|-|-| 5

Here's the common fingerings for these chords. *'s are used for the 2-string inversion, because any finger can be used, as well as combinations of any two adjacent fingers.

Pentatonic Scales

Rock often uses a major or minor Pentatonic or 5-note scale, which is a variation of the classical 7-note major or minor scale. This is used for melodic reasons, not harmonic. Rock music tends to use traditional diatonic harmony for the major or minor scale, including chords that contain notes not found in the penetatonic variation.

The major pentatonic scale simply drops the 4th and 7th from the major scale. The C Major Pentatonic Scale is thus, C - D - E - G - A - C. This drops all half-steps from the scale, including the leading tone.

e--------------------------------8--10--
b--------------------------8--10--------
g--------------------7--9---------------
d--------------7--10--------------------
a--------7--10--------------------------
e--8--10--------------------------------
   C  D  E  G  A  C  D  E  G  A  C  D

The minor pentatonic scale drops the 2nd and 6th from the minor scale. The A Minor Pentatonic Scale is thus, A - C - D - E - G - A. Again, this drops all half-steps from the scale.

e--------------------------------5--8--
b--------------------------5--8--------
g--------------------5--7--------------
d--------------5--7--------------------
a--------5--7--------------------------
e--5--8--------------------------------
   A  C  D  E  G  A  C  D  E  G  A  C

Notice, like the C Major and A Minor, C Major Pentatonic and A Minor Pentatonic consist of the same notes - they are relatives.

These pentatonic scales avoid the tension associated with the leading tone as well as the other half-step normally found in the major/minor scales; yet they clearly have their own tonality which emphasizes the tonic note. The decreased tension follows the general theme in rock which is to avoid strong cadences or resolutions in favor of keeping a musical flow.

Note: there are more pentatonic scales than the two listed above. These are simply the most common for rock music.

Song Structure

Rock songs are typically quite simple, some containing no more than two sections of verse and chorus. Some even use the same harmonic progression for the chorus as the verse. Most do not use modulation, keeping the song in the same tonality, although it might not fit perfectly neatly into a major or minor key. Sometimes, a brief pre-chorus section is used between verse and chorus to create tension or build-up that the chorus will relieve.

The verse is typically more calm than the chorus section, used to establish the tonality, a lyrical theme, and a general mood. It usually does not create musical tension in the harmonic sense but may present a lyrical idea that requires elaboration or resolution. Harmonically, the verse may do nothing or very little. Basically, it is the "calm before the storm" that is the chorus. That doesn't mean it needs to be purposefully boring, only that it doesn't give the listener a sense of completeness.

The chorus is generally shorter than the verse, consisting of a single progression. If the progression repeats it is often only to use a different ending with a stronger resolution. The chorus usually employs larger sonic textures than the verse - "bigger" chords covering more octaves, louder and more resonant cymbals, and background vocals to name a few.

Where modulation occurs in rock music is often to the IV or iv key on a repeat of the chorus. This increases the impact of the chorus without changing its content. In some cases, the verse and chorus will be written in different (but highly-related) keys.

A non-repeating bridge section often occurs between a repetition of the chorus and the final repetition of verse-chorus or the chorus. These are designed to create contrast with the rest of the song but can take a variety of forms. Sometimes it continues the intensity of the chorus but uses a different harmonic theme that builds tension which is released by the ensuing chorus. Sometimes it is completely slow and boring, a kind of super-verse to serve as calm before the intensity of the chorus. Sometimes it is its own complete, yet somewhat brief, musical statement, serving as the climax of the song.

Guitar solos are usually performed during the bridge. Other common placements are over instrumental repetitions of the chorus (or verse (and prechorus) and chorus).

Some songs have intro's or outro's played at the beginning or ending of the song but nowhere else.

Blues Influence

Rock is strongly influenced by Blues. If you notice, the minor pentatonic scale is the same as the blues scale but missing the tritone. Rock is historically an outgrowth of African-American blues merged with swing, country, folk and other genres.

This blues influence has never been completely separated from rock - even modern heavy metal often incorporates some aspects of blues playing. Melodic conventions, blue notes, I - IV - V - I modulations, slow-moving or static harmonies, are all derived from blues backgrounds.

The main technical difference between blues and rock is rock is more energetic and dance-oriented than blues. Following this, rock is more up-tempo and incorporates a back-beat with the snare. Vocal timbres are often more lively or outright screams.

Four Chord Songs: I - V - vi - IV

A simple 3 or 4 chord progression is typical for rock songs, and often strong cadences such as the (V - I) are avoided. One of the more popular progressions is I - V - vi - IV. Remember that one of our example progressions when discussing harmonic function was I - vi - IV - V, which moves from tonic to pre-dominant to dominant function, before resolving back to the I. The I - V - vi - IV progression on the other hand, moves basically in reverse: tonic, dominant, pre-dominant. Its transitions are natural but do not present a strong resolution. When the progression repeats, there is not a strong resolution when returning to I, and the progression seamlessly repeats over and over.

Axis of Awesome's "4 Chord Song" uses this progression. Check out the song - you can hear the effect I'm talking about above. And you can see its popularity, being used in dozens and dozens of recognizable songs.