User:RonniL/sandbox

An important skill in music theory is common practice part writing. While common practice is not incorporated into modern law, its rules are still helpful in understanding and analyzing music. Common law is based on the rules of counterpoint, which is the set of rules that were popularized in the 18th and 19th centuries. Counterpoint aims to create harmonies and progressions that were considered acceptable and enjoyable during that time period.  Users of counterpoint included Bach, Handel, Mozart, Beethoven, and Brahms. This style of writing is often practiced using two parts and divided into different species: 1st, 2nd, 3rd, and 4th, each one encompassing different ways that parts interact with certain rhythms.This practice is best represented in four-part writing, usually chorale style with two voice parts per clef. This writing centers around bass, tenor, soprano, and alto voice parts, the bass and tenor notes being written in the bass clef, and the alto and soprano in the treble. These four voices are used to create chordal progressions. Common practice does not just apply to four part writing; this can apply to a two part piece as well. There are, however, many rules to how these progressions must move.

At the beginning of writing, a composer must concentrate on voice or instrument range and spacing. Whether it is an instrument or a voice, it is important to try to not stretch the range of a part higher or lower than an instrument is usually used to. Spacing is also an important aspect of part writing. Voice crossing, which is when a part goes higher or lower than the part that is above and below them, is forbidden in common practice part writing. An example of this would be the soprano part going lower that the alto part. A subset of this rule is voice overlapping, in which instead of crossing in tandem a voice will go higher and lower than their neighbor just was. For example, the soprano going lower than the alto was the beat immediately before it.

In part writing, the usage of Conjunct Melodic Motion is important, in which the parts generally move in stepwise motion, and in counterpoint, if there is a leap (a jump of a fourth or above), the part will progress the opposite direction it just leapt in stepwise motion. Parts also must progress together in contrary motion, meaning the parts are going in different directions. This is preferable to parallel motion, where the parts move together, or oblique motion, where one part doesn’t move and another does. Parallel motion can be used, but it is important to pay attention to intervals in order to avoid breaking counterpoint rules. Dissonant intervals, both melodic and harmonic intervals are not preferable in most cases. This includes augmented or diminished intervals, tritones, and seventh chords, simply because they sound very jarring in a piece that is meant to sound pleasant to the ear. Parallel intervals, which occur when two parts move the same distance creating the same interval twice in a row, are also important to be aware of. However, this is only a problem when the intervals are either a perfect fifth or a perfect octave. These also can sound uncomfortable to the ear as they tend to have an open or hollow sound.

While consonant intervals (intervals of a third or sixth) and perfect intervals (intervals of a fourth, fifth, eighth) are greatly important, dissonant intervals can occur within music, which is why resolutions are vital. The most basic rule of resolution is to always resolve the leading tone upwards (the leading tones being the 7th scales degree of the key that the piece is in). When resolving the seventh scale degree to the topic, it creates a sense of satisfaction and completion, relieving the tension that it created. Tritones also must be resolved correctly. These can occur in triads or seventh chords that are based on scale degree seven, and they must be resolved correctly. A tritone can either be an augmented fourth intervals or a diminished fifth based on the voicing that the composer uses. In common practice, an augmented fourth must resolve out, meaning the top voice resolves up and the bottom voice resolves down, creating a sixth Opposite of that a diminished fifth must resolve in, where the top voice resolves down and the bottom voice resolves up, creating an interval of a third.