Editing Music theory (section)

===Harmony===
{{Main|Harmony}}
[[File:US Navy 080615-N-7656R-003 Navy Band Northwest's Barbershop Quartet win the hearts of the audience with a John Philip Sousa rendition of.jpg|thumb|[[Barbershop quartet]]s, such as this US Navy group, sing 4-part pieces, made up of a melody line (normally the second-highest voice, called the "lead") and 3 harmony parts.]]
In music, harmony is the use of simultaneous [[pitch (music)|pitches]] ([[timbre|tones]], [[note (music)|notes]]), or [[chord (music)|chords]].{{sfn|Malm|1996|}}{{rp|p. 15|quote=Homophonic texture... is more common in Western music, where tunes are often built on chords (harmonies) that move in progressions. Indeed this harmonic orientation is one of the major differences between Western and much non-Western music.}} The study of harmony involves chords and their construction and [[chord progression]]s and the principles of connection that govern them.{{sfn|Dahlhaus|2009}} Harmony is often said to refer to the "vertical" aspect of music, as distinguished from [[melody|melodic line]], or the "horizontal" aspect.{{sfn|Jamini|2005|loc=147}} [[Counterpoint]], which refers to the interweaving of melodic lines, and [[polyphony]], which refers to the relationship of separate independent voices, is thus sometimes distinguished from harmony.<ref>{{cite web |url=http://sites.fas.harvard.edu/~lab51/theory/html/struct8.html |title=Pitch Structure: Harmony and Counterpoint |author=Faculty of Arts & Sciences |work=Theory of Music – Pitch Structure: The Chromatic Scale |publisher=Harvard University |access-date=2 October 2020 }}</ref>

In [[popular harmony|popular]] and [[jazz harmony]], chords are named by their [[root (chord)|root]] plus various terms and characters indicating their qualities. For example, a [[lead sheet]] may indicate chords such as C major, D minor, and G dominant seventh. In many types of music, notably Baroque, Romantic, modern, and jazz, chords are often augmented with "tensions". A tension is an additional chord member that creates a relatively [[Consonance and dissonance|dissonant interval]] in relation to the bass. It is part of a chord, but is not one of the chord tones (1 3 5 7). Typically, in the classical [[common practice period]] a dissonant chord (chord with tension) "resolves" to a consonant chord. [[Harmonization]] usually sounds pleasant to the ear when there is a balance between the consonant and dissonant sounds. In simple words, that occurs when there is a balance between "tense" and "relaxed" moments.<ref>{{cite web|url=https://shodhganga.inflibnet.ac.in/bitstream/10603/14206/6/06_chapter%202.pdf|title=Chapter 2 Elements and concepts of music (With reference to Hindustani and Jazz music)|website=Shodhganga.inflibnet.ac.in|access-date=3 March 2022}}</ref>{{unreliable source?|date=November 2019|reason=Self-contradictory, self-published?}}