I'm harmonising a tune I've written, in C major, and one chord which resolves to C major consists of B, Db(or C#), F and A. It seems to be a sort of tritone substitution, but I am struggling to come up with an appropriate name for it. There are several options, but their names all sound quite ugly. What would be the best name for the chord? What would be the reasoning behind your answer?

How embarrassing ! Don't know why A got morphed into another note. SORRY !!

  • Can you maybe give the preceding and the following chord? That might help determine the name/role of the chord – Shevliaskovic Oct 27 '14 at 17:41
  • The following chord, as stated, is Cmaj. – Tim Oct 27 '14 at 18:35
  • This underscores the conventionally ignored shortcomings of how chords are usually named in most Western music. We end up doing nutty contortions to name a chord which could just be named by its chromatic intervals as Db 4 9 10. I'd go with Db Aug 7 if pinned down. – Epanoui Nov 12 '17 at 0:17

It's not really in the key but you could call it a Db7#5 since the notes you have can be arranged as Db, F, A, and Cb. It is the simplest name and you could look at it as an altered chord borrowed from the Phrygian mode thus fitting in with resolving to C.

  • 2
    This chord is not borrowed from the Phrygian mode, as the note A natural is not part of C Phrygian (should be Ab). – SeuMenezes Oct 27 '14 at 15:21
  • 1
    @SeuMenezes It can be borrowed and altered (i.e. the 5th is raised the 7th is lowered) – Dom Oct 27 '14 at 15:25
  • @Dom I see, but in this case it could be easier to think of the chord as a substitute dominant. The altered chord loses a lot of its aural association with Phrygian overall sonority. Furthermore, Greek modes do not have intrinsic harmonic functions or chord formations (at least not naturally); OTOH a substitute dominant is sufficiently abstract and bound to the tonal system (the OP states that the chord "resolves into C", hence my reasoning). – SeuMenezes Oct 27 '14 at 15:33
  • Modes have very distinct motions and functions. Ever here of a Phrygian cadence? There's a reason why it's called that. Tritone substitutions are modal in nature and can be traced back from the traditional modes and typical progressions for them. They are not exactly them and are typically altered, but it's much more succinct information to say what mode exactly it's from the just saying it's a tritone substitution. – Dom Jul 25 '15 at 13:42
  • If the B is the lowest note, then one could write D♭7#5/B. – MC Emperor Jul 25 '15 at 14:50

This chord could be named Db7(5+)/B (Db7(5+) with B in the bass). It is a substitute dominant chord (a tritone away from G7, and sharing a tritone with G7 -- that is, F <-> B), altered in its fifth degree, and played in the third inversion (the 7th degree is used in the bass). Its best enharmonic spelling is B-Db-F-A, as Db and A are made to explicitly be a minor second and a major second away from C and G, respectively (C# would be an augmented unison away, which could be at least misleading).


It is indeed a tritone sub of V. I hear it as a G9(b5) with the root (G) replaced by the b5 (Db). So as a chord with root Db it is a Db7/#5, as already pointed out in the other answers. Since it is a tritone sub I wouldn't look at it as "borrowed" from some other mode. Possible scales to play over it are the whole tone scale (of course the one including a G and a Db), and the Db altered scale. Note that the latter scale is (enharmonically) equivalent to a C major scale with the root shifted up by a half tone to Db.

  • Can one call a chord by its root name, but not include that note in the chord? – Tim Oct 27 '14 at 19:58
  • @Tim: I'd say yes, and it's done a lot on the guitar where - depending on context - the root can be left out in order to be able to play extra tension. But in this case there's not need for that, and it's more natural to call it Db7/#5, as suggested. This does not change the fact that I hear it as a V chord, which it is in any case. – Matt L. Nov 3 '14 at 14:10
  • L - I'm happy leaving out a root, provided there's a bass or suchlike to put it in instead. Still deciding whether the 'A' is a #5 or a b13, though... We all seem to agree that it is a tts., I'm just looking for the best name. – Tim Nov 3 '14 at 14:21
  • @Tim: b13 if you prefer to hear the Db altered scale as the chord scale, #5 if you hear the whole tone scale as the chord scale. – Matt L. Nov 3 '14 at 14:33
  • L - Tricky - there's only 3 or 4 notes in that bar, and, obviously, they could belong to either... – Tim Nov 3 '14 at 14:46

As others have suggested, a tritone substitution is probably the best way to look at it. As an additional point of interest, it could also be seen as a form of Augmented Sixth chord on the b2 scale degree. The Db and B form the interval of an augmented sixth, and adding the F makes it an Italian augmented sixth. The French and German aug6th chords would include a G or an Ab respectively. AFAICT, there's no special name for your version of the aug6th chord (where an A is added).


It could be construed as Db7b13 (or C#7b13). The 5 is missing, but it often is in more complex chords, and would clash with the b13 if left in. That chord would be Db, F, (Ab), Cb, no 9th or 11th, but they don't HAVE to appear in 13 chords,and it's not strictly a 13 chord anyway - just a dom 7 with a b13; and Bbb.I'm going for Db rather than C# as the key is C.

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