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Theory ?'s: key sigs/chord scales/accidentals

emor

emor

Guest
May 16, 2004
861
16
#1
This may seem like a dumb and obvious question, but bear with me please.

I am trying to figure out the relationship of key signatures to chords within a piece.

I will use as an example a line adapted from a Patrick Pfeiffer lesson on activebass.com.

It was in TAB form; this is how I notated it (more about that in a minute).

It is a vamp on C7 (right?).

Now, suppose one were to use this riff on a I7-IV7-V7 progression (C7-F7-G7). If I remember correctly, a dominant 7th chord = mixolydian mode (Major scale with b7).

The tonal center is "C" (key signature=no sharps or flats); however, C7 has Bb, F7 has Bb and Eb.

So, question #1: What is the purpose of the key signature?--it seems to apply mainly to establishing the tonal center of the "head" (melody line), and not so much with the chord progression.

Question #2: When you have passing tones, as in the example given, what is the theoretically correct way to notate? (sharp or flat?). For example in the C7 figure, I have already used a flat (Bb=b7 of C), so I used a Gb rather than F#; but moving up chromatically from Bb to C, should it be a B natural or Cb (which seems awkward); but if I used a B natural here, in the G7 figure, wouldn't it be an F# rather than Gb (as I have written)?

Thanks,
emor
 
#2
emor said:
So, question #1: What is the purpose of the key signature?--it seems to apply mainly to establishing the tonal center of the "head" (melody line), and not so much with the chord progression.
Click to expand...


O.K., upon review, that's kind of stupid--it establishes the tonal center of the chord progression, as well, but the notes within the chords are different than those in the key signature.
 
#5
emor said:
This may seem like a dumb and obvious question, but bear with me please.

I am trying to figure out the relationship of key signatures to chords within a piece.

I will use as an example a line adapted from a Patrick Pfeiffer lesson on activebass.com.

It was in TAB form; this is how I notated it (more about that in a minute).

It is a vamp on C7 (right?).

Now, suppose one were to use this riff on a I7-IV7-V7 progression (C7-F7-G7). If I remember correctly, a dominant 7th chord = mixolydian mode (Major scale with b7).

The tonal center is "C" (key signature=no sharps or flats); however, C7 has Bb, F7 has Bb and Eb.

So, question #1: What is the purpose of the key signature?--it seems to apply mainly to establishing the tonal center of the "head" (melody line), and not so much with the chord progression.

Question #2: When you have passing tones, as in the example given, what is the theoretically correct way to notate? (sharp or flat?). For example in the C7 figure, I have already used a flat (Bb=b7 of C), so I used a Gb rather than F#; but moving up chromatically from Bb to C, should it be a B natural or Cb (which seems awkward); but if I used a B natural here, in the G7 figure, wouldn't it be an F# rather than Gb (as I have written)?

Thanks,
emor
Click to expand...
What is the theoretically correct way to notate?
In Theory the key signatures go by the order of sharps and flats
ie F-C-G-D-A-E-B for sharps

B-E-A-D-G-C-F for flats

So In your example G7 we know that G7 is from Cmaj
ie From our modes in C maj we get
I-Cmaj
II-D dorian
III-E phygian
IV-F Lydian
V-G mixolydian ..... etc
So G7 is the V ( fifth ) mode of Cmajor so therefore you would use B natural not F# because the key signature for Cmaj has no sharps or flats
However If G7 was Gmaj then you would use F# because in Gmajor it has one sharp which is of course F
So the key signature's purpose is to group if you like all its related chords in it's appropiate key
Does that help you out a bit
There's some other guys who may hopefully explain in good detail
Anyway a Teacher will help
 
#6
In Theory the key signatures go by the order of sharps and flats
ie F-C-G-D-A-E-B for sharps

B-E-A-D-G-C-F for flats


O.K., I know that.

The next part about the modes I'm not following.
If you have a progression that is C7-F7-G7, wouldn't you be playing:
C mixolydian (C D E F G A Bb C)
F mixolydian (F G A Bb C D Eb F)
G mixolydian (G A B C D E F G)
?

My question about the passing tones has to do with notes not found in the key signature (accidentals) or in the chord scales. Since the example is in the Key of C (no sharps or flats), I assume that the B natural in bar 2 and 4, and the E natural in bar 4 are correct.
But how about the notes (circled in red) In bar 2 and 6? Are they Gb or F#, Db or C#? And how is it determined?
 
#7
I think the notes should be flatted. My reasoning is, look at your scales. If you used A# instead of Bb in C Mixo for example, that would make the note a sharped 6th, not a flatted 7th. I know, they are the same note in that the sound of a Bb == the sound of an A#. BUT, in the scale you derive the chord, the Bb is a flatted 7th (which is what you need for a I7 chord).

So go with the 7th note, then flat it. In G Mixo you're flatting the F# so you get F. In F Mixo, E is the 7th note in the scale so Eb would == flatted 7th. In C Mixo, B is the 7th, so flat the B to get Bb.

Does this make sense to you?
 
#8
You know, I'm not sure it actually matters all that much? (but then I'm not the greatest theory head in the world!)

Generally speaking, I'd avoid using Cb, or E#.. and try to make it consistant, perhaps using #s when the line ascends and b's when it descends?

If there are more strict rules I'm sure someone here can explain better than I... I'd be intersted to learn too.. try posting the same Q in 'music theory' on DB
 
#9
In the C7 sequence, I would write it F#, not Gb, then keep the Bb and B as you have them.

In the F7 sequence, I would *definitely* write B natural, not Cb, then keep Eb and E as you have them.

In the G7, I would write C# instead of Db, and F# instead of Gb.

As for your more general question about there being notes in the riffs that aren't accounted for in the key signature, you've stumbled across a little secret (probably not much of a secret) about much of our popular music, which is that a lot of such music is not perfectly accounted for by standard major-minor theory. In "straight" theory (for lack of a better term), you wouldn't generally have a 7 chord as your I, though that's perfectly acceptable in blues. A I7 in a straight setting is more likely to be functioning not as a tonic but as a V7 of the IV.

Often, the use of a key signature for certain types of popular music is more an indicator of the tonal center of the piece, rather than a strict guide to key as legit theory would have it. Thus, for a blues in D, there will often be a key signature of D major, even if you then have to use a lot of accidentals to indicate how the piece really has to be played, and even if D major, strictly understood, doesn't entirely explain what's really going on. It's kind of a convention.
 
#11
Richard Lindsey said:
Generally, that's not a bad basic policy that will get you acceptably through a lot of situations, though not all. Just remember that flatting an already sharped note means using a natural, not a flat, and sharping an already flatted note also means using a natural.
Click to expand...

Yeah, I just figured it would be easier on the eye :)

Although on reflection, if I wrote a melody Bb B C B Bb over a Bb chord I'd write it B natural both times.

I guess it depends mostly on the chord and what the note does at the time. F# over C7 is the #11. Whereas Gb is the b5, but the natural 5 is still present in the chord... although if it's a passing tone, it's not going to be on a strong beat, so.. :crying:
 
#12
emor said:
In Theory the key signatures go by the order of sharps and flats
ie F-C-G-D-A-E-B for sharps

B-E-A-D-G-C-F for flats


O.K., I know that.

The next part about the modes I'm not following.
If you have a progression that is C7-F7-G7, wouldn't you be playing:
C mixolydian (C D E F G A Bb C)
F mixolydian (F G A Bb C D Eb F)
G mixolydian (G A B C D E F G)
?

My question about the passing tones has to do with notes not found in the key signature (accidentals) or in the chord scales. Since the example is in the Key of C (no sharps or flats), I assume that the B natural in bar 2 and 4, and the E natural in bar 4 are correct.
But how about the notes (circled in red) In bar 2 and 6? Are they Gb or F#, Db or C#? And how is it determined?
Click to expand...

If it has a flat in front of it, then you call it ?b, a sharp in front of it, then ?#. That is the way to call the note. If it is written as Db in notation, you would not call it C#, and vice versa.

b's and #'s are written with the key signature or temporary key or chord symbol for that measure.

If you are in Gmaj, you would write F# (key signature for Gmaj) not Gb.
If you are in Fmaj, you would write a Bb (key Sign again) not a Cbb or A#.

The circle of fourths and fifths are your key to working this out.

Hope this helps.
 
#14
Theory really doesn't help much here since you are using V7 chords.


I would use Db and F# for practical matters based on the chord symbols above them and common usage.

If you can't read what you wrote and make sense of it, where does that leave you. More confusion.

If you want to be more technical and theory based.

G7 (Cmaj) So use of flats and sharps is more free range (usually helps to stick to one or the other)

F7 (Bbmaj) Would use flats.

C7 (Fmaj) would use flats again.

I bring this up because when you are reading and sight reading it is easier to think in flats or sharps (keys, not both at the same time).
 
#16
Theory really doesn't help much here since you are using V7 chords.
Click to expand...
People seem to notate blues just fine?

I bring this up because when you are reading and sight reading it is easier to think in flats or sharps (keys, not both at the same time).
Click to expand...
You have # accidentals in b keys and vice versa.

I think it depends on the scale/chord more than the key. You wouldnt notate Gb in a melody over a C7 chord because it is a #11, not a b5 regardless of the key signeture.
 
#17
Howard K said:
You wouldnt notate Gb in a melody over a C7 chord because it is a #11, not a b5 regardless of the key signeture.
Click to expand...
Actually, you might do just that, depending on the context. F#/Gb doesn't necessrily always function as a #11 in the key of C. If you were playing the notes G-Gb-F, using Gb instead of F# would be IMO both permissible and preferable. If it were going the other way, you'd be more likely to use F#: F-F#-G.
 
#19
I was saying F# functions as a #11 over a C7 chord, regardles of the key.. i.e. Gb is the flatted 5th.

but, yes, fair point.. as a passing tone I guess it makes no difference whatsoeverl.. hang on, I think I said that a few posts ago?... blimey, I'm starting to contradict myself... I'll get my coat... :rolleyes:

re: blues, keys, etc, yeah totally, i was just rejecting the notion that "theory wont help you here!" :D
 

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