S.O.S (ABRSM Music Theory)

[buzzzybeebee]

Is there anyone who can help clear my doubts on the following? Really appreciate....


1) Is the avoidance of consecutive 5ths & 8ves applicable to ANY chord progression? Or does it only applies to IV-V progression?

2) Why is cadence Vb-I not allowed?


Thanks in advance!!

 

[Cheez]

For theory (not real-life application), yes. Avoid parallel 5ths and 8ves in all situations.

Vb-I is allowed as a progression. Not exactly sure what is the question you are asking. Perhaps list the entire 2 chords - the problem may lie elsewhere within the chords.

 

[kongwee]

In real life it sound good, use it. But most importantly, pass your ABRSM theory.Then later read about other theory like Jazz, and listen what they say.

 

[buzzzybeebee]

Hi ALL, thanks alot for helping to clear some of my doubts.

However, I wrote a Vb-I as a cadence in my test, and i was penalised. If like wat u said, Vb-I is allowed in progression, so does it mean it is not allowed in cadences?

And regarding the consecutive 5th & 8ve, if they are to be avoided at all times, then why is the consecutive 8ve in Ic-V-I cadence allowed? If you have the Grade 6 Theory Workbook (By Lee Tack Fah), many of the examples shown to illustrate Cadential 6/4 (which is also Ic-V-I) has consecutive 8ves.... *scratch head*

Appreciate your advice....

 

[Cheez]

Can you show the example given by the Workbook?

 

[buzzzybeebee]

Ok, regarding the "Vb", the question was to harmonise the given melody for SATB. The song was in Bb Major key, and the melody at the end of the song was D-C-Bb (Mi-Re-Doh), so i wrote I-Vb-I respectively as its final cadence, but i was given a big cross on my "Vb".

As for the consecutive 8ves in Ic-V-I cadence. The supplementary book wrote in using SATB format. So, in a C major key, starting from the bass (B) note to the Soprano (S) note, it was written as:

Chord Ic: G, G, C, E
Chord V: G, G, B, D
Chord I: C, E, C, C

As you can see, there is an consecutive 8ve between chord Ic & V within tenor & bass...

 

[kongwee]

Ok, regarding the "Vb", the question was to harmonise the given melody for SATB. The song was in Bb Major key, and the melody at the end of the song was D-C-Bb (Mi-Re-Doh), so i wrote I-Vb-I respectively as its final cadence, but i was given a big cross on my "Vb".

I don't study ABRSM. But why you use Vb instead ii or V. Vb have E,G# and B key which is not in scale key. Of cos, it is very cool to end like that in non classical way.

 

[Cheez]

buzzybeebee, that's not a parallel 8ve. P5 and P8 happens when the notes move in parallel. In your example, the notes remains the same (not moving). In fact, they can be tied and hence held stationary. P5 would be something like C,G moving to D,A; P8 is C,C moving to D,D. Repeating the notes is not a problem. It's when they move in parallel when the problem occurs.

Kongwee, Vb is not V flat. It's the first inversion of V (ie in the key of C, the bass note is B). We use "b", "c" and "d" to indicate 1st, 2nd and 3rd inversions (3rd inversions only in 7th chords). "a" is hence root position, but we don't usually write that.

buzzybeebee, can you give the notes of the Vb-I chord? I'm pretty sure inverted/leading note cadences are no problem. It might be a problem with your chord structure.

 

[buzzzybeebee]

Hi Cheez, my doubts on the Ic-V-I cadence is cleared!! Thanks alot on that!!

As for the Vb-I, in the key of Bb major, last 3 melody notes, below is wat i wrote (from bass to soprano)...

Vb: A, C, F, C
I: B, B, D, B

 

[Cheez]

Can you let us know the exact notes on the staff? It's difficult to know which notes they are on the staff (which octave). Tripling the Bb in the I is ok, although I would include the dominant. Depends on the exact notes of the Vb.

 

[Cheez]

buzzybeebee, did you solve the problem?