C#min7

Construction

Built from these intervals: 1-b3-5-b7. The b3 sets the minor quality. The b7 -- ten half steps above the root, or two half steps below the octave -- adds warmth without creating a tritone (the interval of six half steps). No tritone means no pull toward resolution; this chord settles rather than drives. The absence of a tritone is exactly why min7 cannot function as a dominant chord. Min7 is the minor triad with a b7 added.

Harmonic Function

In Roman numeral analysis (uppercase = major, lowercase = minor):

• ii7 in major keys -- the most common role, launching the ii7-V7-I progression that runs through virtually every jazz standard. As a ii chord, min7 is built from Dorian (a minor scale with a natural 6th).
• iii7 in major keys -- mediant (the chord built on the third degree), often a passing chord between IV and ii.
• vi7 in major keys -- relative minor with added color, deepens the emotional weight of major-key progressions.
• i7 in minor keys -- tonic in minor, stable enough to rest on, though min(maj7) sometimes replaces it for harmonic minor flavor.

Character

As a member of the minor seventh chord family, min7 is warm and relaxed. Where dom7 creates tension through its tritone (between 3 and b7), min7 has no such friction -- the b3 and b7 produce an interval of a perfect fifth, not a tritone. Compare to dom7: the only structural difference is b3 versus natural 3, but that one interval eliminates the tritone and transforms the chord from restless to settled. Min7 is contemplative rather than urgent.

Related Sounds

These chords are closely related -- each modifies one interval from the min7 foundation:

• dom7 (1-3-5-b7) -- natural 3 instead of b3, creates the tritone that min7 lacks
• min6 (1-b3-5-6) -- 6 instead of b7, implies Dorian specifically and feels more stable
• min9 (1-b3-5-b7-9) -- adds the 9 for openness
• min11 (1-b3-5-b7-9-11) -- spacious, modal jazz sound
• min7b5 (1-b3-b5-b7) -- half-diminished, darker and more tense due to the b5

Voice Leading

Voice leading tracks how individual notes move from one chord to the next. Min7 chords flow naturally in descending-fifth motion, making them the connective tissue of jazz progressions.

• ii7 to V7: The b3 of ii7 stays as the b7 of V7 -- a common tone. The b7 of ii7 moves down a half step to the 3 of V7. The 5 steps down to the root of V7. This half-step motion is the engine of ii-V.
• vi7 to ii7: The root of vi7 holds as the 5 of ii7, and the b3 holds as the b7 -- two common tones. The b7 of vi7 moves down to the b3 of ii7. The 5 steps down to the root of ii7.
• iii7 to vi7: The root of iii7 holds as the 5 of vi7, and the b3 holds as the b7 -- two common tones. The b7 of iii7 moves to the b3 of vi7. The chain of descending fifths feels inevitable, which is why it drives jazz harmony.

These movements apply in any key -- the intervals are the same regardless of root.

Practice Seeds

ii-V-I drilling. Practice ii7-V7-Imaj7 in several keys. This is the most important progression in jazz -- make the voice leading automatic and listen for the common tones connecting each chord.

Compare to dominant. Play min7, then dom7 on the same root. The only difference is b3 versus natural 3, but dom7 has a tritone and demands resolution while min7 rests. This comparison isolates what a tritone does.

Voice the seventh. Play min7 with the b7 in different positions -- low, middle, high. Notice how placement changes the warmth and darkness of the chord.

Track through changes. In a jazz standard, find every min7 chord. Is it functioning as ii, iii, vi, or i? Context determines its role -- the same chord sounds different in each position.