Editing Altered chord (section)

==Background==
{{Image frame|content=<score sound="1"> {
\relative c' {
   \clef treble
   \time 4/4
   \key c \major
   <c e g>1 <bes d f> <aes c es> <bes d f> <c e! g> \bar "||"
} }
</score>|width=345|caption=Chord progression with chords borrowed from the [[parallel minor]]}}
"Borrowing" of this type appears in music from the [[Renaissance music]] era and the [[Baroque music]] era (1600–1750)—such as with the use of the [[Picardy third]], in which a piece in a minor key has a final or intermediate cadence in the tonic major chord. "Borrowing" is also common in 20th century [[popular music]] and [[rock music]].

For example, in music in a major key, such as C major, composers and songwriters may use a B{{music|b}} major chord, that they "borrow" from the key of C minor (where it is the VII chord). Similarly, in music in a minor key, composers and songwriters often "borrow" chords from the tonic major. For example, pieces in C minor often use F major and G major (IV and V chords), which they "borrow" from C major.

More advanced types of altered chords were used by [[Romantic music]] era composers in the 19th century, such as [[Chopin]], and by [[jazz]] composers and improvisers in the 20th and 21st century. For example, the [[chord progression]] on the left uses four unaltered chords, while the progression on the right uses an altered IV chord and is an alteration of the previous progression:<ref name="Erickson">[[Robert Erickson|Erickson, Robert]] (1957). ''The Structure of Music: A Listener's Guide'', p. 86. New York: Noonday Press. {{ISBN|0-8371-8519-X}} (1977 edition).</ref>

:{|
|<score sound="1">
   \new PianoStaff <<
      \new Staff <<
         \new Voice \relative c'' {
             \stemUp \clef treble \key c \major \time 3/4
             c4 c b c2.
             }
         \new Voice \relative c' {
             \stemDown
              e4 f d e2.
              }
            >>
     \new Staff <<
         \new Voice \relative c' {
             \stemUp \clef bass \key c \major \time 3/4
             g4 a g g2.
             }
         \new Voice \relative c {
             \stemDown
             c4_\markup { \concat { "I" \hspace #1.5 "IV" \hspace #1 "V" \hspace #3.5 "I" } } f g c,2. \bar "||"
             }
         >>
    >>
</score>
|<score sound="1">
   \new PianoStaff <<
      \new Staff <<
         \new Voice \relative c'' {
             \stemUp \clef treble \key c \major \time 3/4
             c4 c b c2.
             }
         \new Voice \relative c' {
             \stemDown
              e4 f d e2.
              }
            >>
     \new Staff <<
         \new Voice \relative c' {
             \stemUp \clef bass \key c \major \time 3/4
             g4 aes g g2.
             }
         \new Voice \relative c {
             \stemDown
             c4_\markup { \concat { "I" \hspace #1.5 "iv" \hspace #1.5 "V" \hspace #3.5 "I" } } f g c,2. \bar "||"
             }
         >>
    >>
</score>
|}

The A{{music|b}} in the altered chord serves as a [[leading tone]] to G, which is the [[root (chord)|root]] of the next chord.

{{Blockquote|The object of such foreign tones is: to enlarge and enrich the scale; to confirm the melodic tendency of certain tones...; to contradict the tendency of others...; to convert inactive tones into active [leading tones]...; and to affiliate the keys, by increasing the number of [[common tone (scale)|common tone]]s.<ref name="Goetschius"/>}}
{{Image frame|content=<score sound="1" override_midi="Franck - Symphonic Variations augmented seventh chord.mid">
    {
      \new PianoStaff <<
        \new Staff <<
            \relative c'' {
                \clef treble \key fis \minor \time 3/4
                r8. <g a cis eis>16 <g a cis eis>8. <fis d' fis>16
                <fis d' fis>4 r8. <d fis d'>16 <d fis d'>8. <a' c dis a'>16
                <a c dis a'>4
                }
            >>
        \new Staff <<
            \new Voice \relative c, {
                \clef bass \key fis \minor \time 3/4
                r8. <a a'>16 <a a'>8. <d d'>16
                <d d'>4 r8. <d d'>16 <d d'>8. <fis, fis'>16
                <fis fis'>4
                }
            >>
    >> }
</score>|width=390|caption=The augmented fifth often appears in the soprano [[part (music)|voice]], as here in [[César Franck|Franck]]'s ''[[Symphonic Variations (Franck)|Symphonic Variations]]''.<ref name="Harmony">[[Edward Aldwell|Aldwell, Edward]]; [[Carl Schachter|Schachter, Carl]]; and Cadwallader, Allen (2010). ''Harmony & Voice Leading'', p. 601. {{ISBN|9780495189756}}.</ref>}}

According to one definition, "when a chord is chromatically altered, and the thirds remain large [major] or small [minor], and is not used in [[modulation (music)|modulation]], it is an altered chord."<ref>Bradley, Kenneth McPherson (1908). ''[https://books.google.com/books?id=7ucsAAAAYAAJ&dq=%22altered+chord%22&pg=PA119 Harmony and Analysis]'', p. 119. C. F. Summy. {{pre-ISBN}}</ref> According to another, "all chords...having a major third, i.e., either triads, sevenths, or ninths, with the fifth chromatically raised or chromatically lowered, are altered chords," while triads with a single altered note are considered, "changes of form {{bracket|[[chord quality|quality]]}}," rather than alteration.<ref>Norris, Homer Albert (1895). ''[https://books.google.com/books?id=FMYPAAAAYAAJ&dq=%22altered+chord%22&pg=RA2-PA52 Practical Harmony on a French Basis, Volume 2]'', p. 48. H.B. Stevens. {{pre-ISBN}}</ref>

According to composer [[Percy Goetschius]], "Altered...chords contain one or more tones written with [[accidental (music)|accidentals]] ({{music|#}}, {{music|b}}, or {{music|natural}}) and therefore foreign to the scale in which they appear, but nevertheless, from their connections and their effect, obviously belonging to the principal key of their [[phrase (music theory)|phrase]]."<ref name="Goetschius">[[Percy Goetschius|Goetschius, Percy]] (1889). ''[https://books.google.com/books?id=Q_0sAAAAYAAJ&dq=%22altered+chord%22&pg=PA147 The Material Used in Musical Composition]'', pp. 123–124. G. Schirmer. {{pre-ISBN}}</ref> [[Richard Franko Goldman]] argues that, once one accepts, "the variability of the scale," the concept of altered chords becomes unnecessary: "In reality, there is nothing 'altered' about them; they are entirely natural elements of a single key system,"<ref>[[Richard Franko Goldman|Goldman, Richard Franko]] (1965). ''Harmony in Western Music'', pp. 83–84. Barrie & Jenkins. {{ISBN|0-214-66680-8}}</ref> and it is, "not necessary," to use the term as each 'altered chord' is, "simply one of the possibilities regularly existing and employed."<ref>Goldman (1965), p. 47.</ref>

[[Dan Haerle]] argues that only fifths and ninths may be altered, as all other alterations may be interpreted as an unaltered chord tone or, enharmonically, as an altered fifth or ninth (for example, {{music|#}}1 = {{music|b}}9 and {{music|b}}4 = 3).<ref name="Haerle" /><ref name="Alfred">Alfred Music (2013). ''Mini Music Guides: Piano Chord Dictionary'', pp.  22–23. Alfred Music. {{ISBN|9781470622244}}</ref>