Major b6 substitute?

[derek]

I ran across a tune last night with a student that blatantly used a major7th chord a b6 from the key. The sig was in F, and it alternated between ii V in Bb, and ii V in F, but each time the ii V's would resolve to a Dbmaj7, not Bb or F. I have not run across this before, and was hoping for some enlightenment. Thanks.

[JohnW400]

Well,

Dbma7 resembles Bbmi7 and it also resembles Fmi. So I'm guessing that's why it sound's ok.

If he made it Dbma7#5 I could see it as closer to the Fma.

It could be "borrowed" from some classical theory like a Neopolitan 6 or such but I can't remember much about all those ethnic 6th's and such.

Maybe Randall might know.

[derek]

Just heard back from Tony DeCaprio. He called this a b6 major sub, or a deceptive cadence using a flat sub-mediant major. The b6 and tonic share the root and 5th, which I guess are the strongest tones other than 3rd and 7th.

[randalljazz]

what was the tune?

[derek]

Originally Posted by randalljazz

what was the tune?

Something off of kindormusic.com called Glazed Over. Jazz bass student brought it in, and I had not seen that used before.

[bako]

A reharm technique is to substitute a chord in a 3rd relationship to the original chord above and below.

Diatonically Dm7/Fma7/Am7 or Gm7/Bbma7/Dm7

Taking it out of the key signature can expand the palette.
Because of the 3rd relationship some notes will overlap. Those that don't will still be just a half step away.
To increase common tones we can do as JohnW suggests to alter notes to bring the 2 chords closer if we want.

Dbma7/Fma7/Abma7 or Gbma7/Bbma7/Dbma7

This is one possibility.

[fep]

In classical theory a Dbmaj7 in the key of F major would be considered a "Borrowed" harmony notated as a bVI7. Borrowed chords, also referred to as "modal borrowing", are chords that are diatonic to the parallel minor, in this case the parallel minor being F minor. The most common borrowed chords are the viio7, iio, ii half-dim, iv, and the bVI.

Also in a minor key ii - V - (b)VI is the most common "Deceptive Cadence"

Coincidentally, I had to analyze this relationship on a music theory final I took today.

An example I really like of modal borrowing is in A Child is Born. The first several measures Bbmaj7 | Ebm/Bb | Bbmaj7 | Ebm/Bb etc. Here the borrowed harmony is the iv chord.

[derek]

Originally Posted by fep

In classical theory a Dbmaj7 in the key of F major would be considered a "Borrowed" harmony notated as a bVI7. Borrowed chords, also referred to as "modal borrowing", are chords that are diatonic to the parallel minor, in this case the parallel minor being F minor. The most common borrowed chords are the viio7, iio, ii half-dim, iv, and the bVI.

Also in a minor key ii - V - (b)VI is the most common "Deceptive Cadence"

Coincidentally, I had to analyze this relationship on a music theory final I took today.

An example I really like of modal borrowing is in A Child is Born. The first several measures Bbmaj7 | Ebm/Bb | Bbmaj7 | Ebm/Bb etc. Here the borrowed harmony is the iv chord.

Thanks fep. Seems I learn something new about this stuff all the time. So much to explore. I am starting to think about these b6 major7 chords as subs for ending chords on chord melody tunes to try them out.

I have heard what you are talking about "borrowing" as modal interchange.

[Decapriology1]

The flat-submediant major is a common sub for the Imaj7 chord (relative major of the actual submediant). It is an "offshoot", if you will of the relative minor ("sub-mediant minor") as in this case D-7 from it's relative major, Fmaj7. What makes it a good deceptive cadence change? Namely two strong common tones shared with Fmaj7; F and C. When the root and fifth of the original change are present in the sub change, you usually can expect a homerun (or at least a triple), when taste is present and the surrounding harmony obliges easily. Another viewpoint ( or cross-checking) is the fact that Db is often looked upon by modern theorists as the "harmonic root." It is a third below.
Play F on your guitar and sing Db below and vice versa. Db is "reciprocal" to F and F is "overtonal" to Db. You can't miss. I often tweek the Dbmaj7 to Dbmaj7#4 as a sub for Fmaj7. In addition, instead of C7 going to F as perfect cadence, I may play G-7 to Dbma7 to F as a 'deceptive V change', yet closely related to this harmonic family. In fact doing so, as your experiment in sound, will make such harmonic affinity that much more transparent.

-TD

[mattymel]

bVI, bVII, bIII, bII, iv, bVII7...modal interchange chords...super common in jazz tunes. even common in good pop music. david bowie, etc...though i doubt he would call it that.