Applied dim7 chords

I believe I have been requesting for this since ~6 years ago, and little progress has been made since then. Are there any plans to support viio7/ chords?

As I stated before this is the one important chord that is still unavailable in Hookpad after all these years. Take F♯dim7 - G in C for example:

  • ♯ivo7 is equivalent to viio7/V, but this chord and its inversions cannot be inputted without temporarily switching to a different relative key. It doesn’t help that the chord search database excludes supermodes of the harmonic minor scale.
  • viio/V (diminished triad) is not substitutable in case of F♯dim7/E♭ - G/D, as the diminished seventh is in bass position.
  • The tone set tool suggests (add6)(♭5), which is notationally wrong. These chords also miss a third inversion.

Hey @HertzDevil,

Sorry about this, it’s been on our list for a while but never materialized. We’ll make this happen now.

Probably we’ll just make viio7/x the default applied viio seventh chord, since I see no musical justification for the half diminished version. There are some theorytabs in the database which have analyzed ♯ivø7 as viiø7/V, so these will need to be swapped with ♯ivø7(lyd)

How many viiø7/ chords are there in current use? (The Trends page gives 40 results for viiø7/V alone, but there are probably more.) Can this replacement be automated on the server side before the fully diminished version rolls out?

In principle yes, this is possible, although we generally are hesitant to do any automated modification of theorytabs.

I took a look at the database and have counted the following:

viiø7/ii: 4 results
viiø7/iii: 1 result
viiø7/IV: 44 results
viiø7/V: 4 results
viiø7/vi: 6 results
viiø7/viio: 2 results

However, not sure if these are all correct. Also, not all of these chords have simple equivalents. It might be worth going through some of these analyses to double check the chords, at least for the analyses containing the chords that aren’t viiø7/IV

Even though it’s not common it’s still used. Just like how Locrian is not common but is still used. How about we have the ability to use both

Agree with you, but it’s not that these chords aren’t useful, it’s just that most of them can be spelled in different ways that are probably more accurate from a music theory perspective.

By far the most common of these, is viiø7/V, which in C major would be a F#m7(b5). However this can be spelled as ivø7 (lyd), which is probably more correct. The other common one is viiø7/IV, which can be spelled iiiø7(mix).

Functionally, viiø7/x does not have a tendency toward their x, it’s just kind of a hack to get a half diminished quality. Conversely viio7/x functions like viio/x and has an important role in many types of music.

@Ryan Sometimes viiø7/x does have tendency to x, e.g. in this theorytab. The E°7 and F#°7 are supposed to be Em7(b5) and F#m7(b5) respectively. They resolve to their target chords, F and G respectively

Another example:

The Cm6 (viiø65/V) resolves to V7

You’re completely correct, I shouldn’t have said there is no tendency, but according to our data, the two most common uses of half diminished 7th chords are in the minor turnaround iiø7 → V7 → i, and #ivø7(lyd) → I64 as a precadence to V (actually, a popular Christmas song device), the latter of which I think is a fine spelling of the progression.

While it’s true that the Mario song uses viiø7/V, I think this is more the exception than the rule. IMHO i’m guessing the reason the guitar is playing SDs 3 and 6 over the #4 bass is more of a finger holdover from the IV7 chord than by design. And the Fig Leaf Rag example actually has so many applied fully diminished sevenths, that I think this is evidence of how important this latter chord is.

Ultimately the way I see it there’s a tradeoff to be made, and we feel better about moving this direction.