Theory Question on this bass line

[Photonic]

Greetings. I am working with a bassline over a gospel style exercise and am wondering about one particular note choice which seems to be out of key. Chart attached.

My assumption on this piece is that it is in the key of Bb. The walk down from measure 17-23 I am assuming is a 5 > 4> b3 > 2 descending line.

My question is why the Db is chosen in bar 21 instead of a D (which I am assuming is in the key). I have drawn a red box around the note in question. Perhaps a b3 for a 3 substitution is common? Or perhaps I have the key all wrong since this is a blues type progression.

Can you help me understand? Thanks so much!

 

[AGCurry]

Definitely the key of Bb. Real music is full of unexpected chords, and they're not wrong.
Without context of melody, we can't really know what the reason for the Db chord is, but rest assured that there IS a reason, and it's probably musically valid. Assuming that the chart's chords are accurate, you must play a Db (as opposed to D natural).

 

[Photonic]

Definitely the key of Bb. Real music is full of unexpected chords, and they're not wrong.
Without context of melody, we can't really know what the reason for the Db chord is, but rest assured that there IS a reason, and it's probably musically valid. Assuming that the chart's chords are accurate, you must play a Db (as opposed to D natural).

Thanks so much for that! Here is the audio.

 

[pmatz2]

Thanks so much for that! Here is the audio.

it’s not uncommon to see chords borrowed from the parallel minor key. In this case the d flat major is borrowed from b flat minor. They can help make your chord progressions more interesting.

 

[Photonic]

it’s not uncommon to see chords borrowed from the parallel minor key. In this case the d flat major is borrowed from b flat minor. They can help make your chord progressions more interesting.

That is very interesting - Thanks!

 

[Whousedtoplay]

Chart attached.

I'm trying to figure out that Cm/Fb notation.

My question is why the Db is chosen in bar 21 instead of a D

It's so strange that you don't ask about having that C7 chord in the key of Bb.

Perhaps a b3 for a 3 substitution is common? Or perhaps I have the key all wrong since this is a blues type progression.

(It's only my amateur musician's opinion!)

Let's explore the track's form - 24 bars/measures or 2 x 12 bar blues form.
The Db-in-question is in the 21st bar/measure.
The simple blues form would call for the Tonic (7th) chord in that measure, but the "composer" of that track has decided to slightly rearrange (to tweak) that simple Blues chord progression by changing it - numerous players have done it.
If I'm the "composer" of that track, I would try to "reinvent"(LOL) the song's (blues) harmony.
My goal is to get to the dominant chord of Bb - I need to end up on that F(7).
I can try to use my favorite harmonic progression template - the Circle of Fifths.
What if I play G7b9 after Eb7(9) and move to C7 and finish on F7?
What if I use a tritone substitution of Db7 (in place of the G7 chord) to get to the secondary dominant of C7?
Sounds refreshing to me.
Now, let's go backwards.

F7 - it's the Dominant chord of Bb
C7 - comes to us as the secondary dominant of F(7).
Db7 - we got it as a tritone substitution in place of G7b9.

 

[Whousedtoplay]

Now, let's look at that Cmin/F chord construction.
Yes, it sounds MINOR for sure but...

It reminds me of F11.


The F eleventh is a six-note chord. To avoid dissonance the third (A) is normally omitted. The chord is also often played inverted. The chord is abbreviated as F11.

We have a simple cadence in the bass as IV - V - I (Eb - F - Bb) but the chords on top have a different "seasoning.

 

[Photonic]

It's so strange that you don't ask about having that C7 chord in the key of Bb.

LOL. I guess this really isn't three chord folk music!

 

[micguy]

The point of theory is to gain an understanding (in an academic sense) of what sounds good, what doesn't and try to explain why. Theory shouldn't drive musical decisions, what it sounds like is the criteria you use to decide what to play. The mp3 sounds good - I don't hear anything unmusical. That means any discussion is academic, and exists only to explain why it sounds good. If it sounds good (or even if it sounds bad, but it sounds as the composer intended), there aren't (by definition) wrong notes or chords.

 

[Bob_Ross]

I'm trying to figure out that Cm/Fb notation.
View attachment 5033432

Since the tune is in the key of Eb, [edit: No it isn't what was I thinking?!?! see below] and because the proceeding chord has an Eb in the bass, the copyist wanted to make it explicitly clear to the performer that this note is conspicuously different from Eb. If they had simply written an E natural, that difference -- and the half-step motion from the proceeding chord -- might not be so obvious to someone sight reading the changes.

As to what that Cm/Fb is supposed to sound like... well, in root position it sounds like pure crap, so maybe the arranger had a more specific voicing in mind? :::shrugs:::

 

[Don Kasper]

C'mon, everybody - the "Cmin/Fb" is a TYPO - there is a written "F natural" note in the staff of the sheet music.
And...if you listen to the audio track, it is an F in the bass.
Jeez....
You're Welcome.
Thanks.

 

[dbsfgyd1]

Thanks so much for that! Here is the audio.

This sounds fine to me.

 

[Carl Hillman]

My question is why the Db is chosen in bar 21 instead of a D (which I am assuming is in the key).

Without seeing what the melody is doing there, I can only guess that the essential reason it's Db9 instead of Dm is because it sounds good.

Perhaps a b3 for a 3 substitution is common?

I would analyze it as a tritone substitution for a VI7 chord, and I would treat it like a Db9#11.

 

[Photonic]

C'mon, everybody - the "Cmin/Fb" is a TYPO - there is a written "F natural" note in the staff of the sheet music.
And...if you listen to the audio track, it is an F in the bass.
Jeez....
You're Welcome.
Thanks.

Yes that Fb is clearly a typo!

 

[Wasnex]

It's 'cause I got d'bluuuuuues baby.

My little semi-literate brain hears what I would describe as harmonic sequence using dominant chords that descend in whole steps.

Not sure if harmonic sequence is the correct term. But this sort of thing is not uncommon: One kat makes up a non-functional chord progression that sounds cool...and next thing you know a bunch of other kats are copying it.

 

[themickster]

Greetings. I am working with a bassline over a gospel style exercise and am wondering about one particular note choice which seems to be out of key. Chart attached.

My assumption on this piece is that it is in the key of Bb. The walk down from measure 17-23 I am assuming is a 5 > 4> b3 > 2 descending line.

My question is why the Db is chosen in bar 21 instead of a D (which I am assuming is in the key). I have drawn a red box around the note in question. Perhaps a b3 for a 3 substitution is common? Or perhaps I have the key all wrong since this is a blues type progression.

Can you help me understand? Thanks so much!

If it sounds right, it is right.

 

[petermwright]

Since the tune is in the key of Eb, and because the proceeding chord has an Eb in the bass, the copyist wanted to make it explicitly clear to the performer that this note is conspicuously different from Eb. If they had simply written an E natural, that difference -- and the half-step motion from the proceeding chord -- might not be so obvious to someone sight reading the changes.

As to what that Cm/Fb is supposed to sound like... well, in root position it sounds like pure crap, so maybe the arranger had a more specific voicing in mind? :::shrugs:::

The tune is in B-flat rather than E-flat, but in any case, the F-flat is a typo - you can see the notated note is F-natural. All the other times that chord comes up it says F, too.

 

[petermwright]

I'm pretty sure "Fb" is how you spell an "E" note in the key of Bb.

There is not a single right way of doing it. It depends on the context. If I were notating it I’d use E-natural if I could, because most people would rather read E-natural than F-flat. In some circumstances that would get awkward (e.g alternating between E and Eb - E Eb E Eb etc), but unless that’s the case I’d probably choose E-natural.

 

[Bob_Ross]

The tune is in B-flat rather than E-flat, but in any case, the F-flat is a typo - you can see the notated note is F-natural. All the other times that chord comes up it says F, too.

derp, you’re right, I’m an idiot. Not sure what I was thinking when I saw that key signature!

And Cm/F sure sounds a whole lot less craptastic than Cm/Fb in that context!

 

[Groove Master]

Db in the key of Bb is simply a blues harmonization. It is also a very typical chord progression.