While reading up on four-way close voicing (part of Evan Rogers' Big Band Arranging series), I have encountered something I cannot quite understand, so maybe there is a typo in the article?

The picture below is four-way close voicing; the green notes are approach notes:

enter image description here

With regards to the second chord under which "DOM." is written, I first thought it was B D F Ab (B fully diminished chord) without knowing it was dominant function, resolving to C/A.

After seeing the "DOM." written under it, I presumed the author meant a rootless G7(b9), Ab B D F. But as you can see above the author adds an explanation beneath "I substitute the root of the chord (E) for the b9 (F) ..." implying it is rootless E7(b9). Is this a typo or have I not yet understood it properly?

And with regards to the fourth chord under which "DIM." written, in order to be a fully diminished chord, A has to be Ab, forming B D F Ab. I also wonder why A is sustained?

  • What book or web site is this from? Seems strange to say there's an E chord of some sort when there's no chord symbol for it. Commented Jul 8 at 2:26
  • The same paragraph says "We don't want an awkward repeated E in the same voice", which substituting E for F in the culprit chord creates. I think the author mixed something up.
    – Dekkadeci
    Commented Jul 8 at 4:49
  • 1
    What on earth is Ab supposed to be doing in an E chord?
    – Divizna
    Commented Jul 8 at 5:47
  • 2
    @Divizna enharmonic equivalence, diminished seventh chord symmetry, harmonic ambiguity.
    – phoog
    Commented Jul 8 at 6:23
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    It's possible that what the author really means is that they substitute the b9 (F) for the root (E) of the "dominant" approach chord, changing it from E7 to Bdim7 (or poorly spelled G#dim7). Thing is, G#dim7 makes the most sense if the chord following it is Amin7, while Bdim7 makes the most sense if the chord following it is C6. Amin7 and C6 use the exact same notes, so the headaches continue...
    – Dekkadeci
    Commented Jul 8 at 6:45

3 Answers 3


If this is truly a dominant approach then the chord is G7 and you are right. The root is G and he replaced the root (G) with the b9 (Ab) so E and F in the text must both be typos.

The thing is by replacing the root with the b9 you actually end up with a rootless G7b9, which is actually a Bo7. That actually makes it a diminished approach, Bo7-C6 so you can also call it a diminished approach.

As for the next diminished approach, as written it is a Bm7b5, or half diminished, which happens to be diatonic to C. It could be that in this system a half diminished chord can be considered a diminished approach. However, based on his reasoning of avoiding repeating notes and having it be a true diminished approach, this chord SHOULD be a Bo7 and have an Ab like you said. It is possible the Ab accidental on that chord is also a typo, an omitted flat sign on the A note.

That is two significant mistakes in just one bar…

  • 3
    Also the backward use of "substitute": it's too widespread now to be wrong, but it confuses me every time.
    – phoog
    Commented Jul 9 at 13:40
  • @phoog Now that you mention it, you’re right about “substitute”. It didn’t seem right to me but I didn’t give it much thought when I answered. Commented Jul 9 at 13:53
  • @phoog Could you enlighten me what you meant by "backward use of 'substitute'" ? Commented Jul 9 at 14:05
  • @GratefulDisciple I think I can. If you substitute X for Y then Y is the original and X is the substitute, in this case X is used as the original. Commented Jul 9 at 14:50
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    @JohnBelzaguy Oh, a matter of English language, I thought it's some esoteric jazz theory :-) . Commented Jul 9 at 14:51

Based on some of your previous harmony question, I would suggested using different sources for study, and probably not jazz but "classical" sources, because those tend to provide stricter definitions, and your questions dig into those fine details. I don't mean completely abandon jazz harmony study. I only mean you should definitely get a good, classical harmony book to learn standard definitions and functions. That can help you understand the idiosyncrasies of some jazz teaching.

In your example the labels are simply DOM and DIM, and there really isn't much in the textual part to explain any special meaning for those labels. Without any such explanation, I take those labels to mean any dominant function and any kind of diminished chord.

The first, labelled DOM, is a full diminished seventh chord rooted on the leading tone, and that chord is certainly a type of dominant. Also, check your spelling of that chord, you mis-identified the B♮ leading tone as B♭.

The second, labelled DIM, is a half diminished chord, which is a type of diminished chord, given the normal meaning of a diminished chord is one where the interval between root and fifth is a diminished fifth.

It's hard to say more about an isolated example. To me, it looks like a kind of catalog of types of passing chords.


First of all, you should have linked the article for the whole context, which is part 10 | Voicings (Part 1) of Evan Rogers' Big Band Arranging series.

Yes, I think he has a typo in the sentence

"I substitute the root of the chord (E) for the b9 (F) ..."

The dominant 7 chord is G7, so he should have said

"I substitute the root of the chord (G) for the b9 (A-flat) ..."

Then in the notes, you are right again. He forgot to add a flat to the bottom A of the 4th chord, to make it a fully diminished 7 chord, as you can hear it in the sound clip. Then of course he needs to add a natural sign for the bottom A of the 5th chord.

When those typos are corrected, the labels "Dom" and "Dim" will make sense, but see @JohnBelzaguy's answer for an argument that the first transition should also be a Dim, in addition to affirming your 2 findings as well. (I wrote this answer before I read his.)

P.S. You may want to contact Evan Rogers to correct his typos so other students wouldn't get confused.

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