[Smt-talk] Parallel Fifths

[Ninov, Dimitar N]

Dear List,

Yes, I agree with Prof. Vaisala on Bach's usage of vii6-I or vii6-I6 with parallel fifths of unequal size. I also implied that composers are  usually cautious about those kinds of fifths, and in most cases they are applied there is a bass or another voice which moves in thirds and sixths with each of the voices that form the fifths. This does not negate the fact that they have been used otherwise.

But I also implied that the mere fact that one fifth is diminished and another - perfect - does not provide an automatic license for convincing connection, nor do composers use those fifths indiscriminately just because of their different quality.

Yes, I think that the harmonization of a soprano line Sol-Fa-Mi with Cad. 6/4 - V7 - I is the least successful and idiomatic one because of the prominent parallel fifths that come forward and are not placed in those favorable conditions I mentioned above. This soprano fragment will be more typically harmonized with V-V6/5 - I, or V-vii dim. 7/vi-vi, or I6-V4/3-I, or I6-vii6-I. All these progressions contain a motion in the bass that moves nicely and favorably along or against the parallels and attracts the attention to other factors.

Thanks,

Dimitar Ninov

Dr. Dimitar Ninov, Lecturer
School of Music
Texas State University
601 University Drive
San Marcos, Texas 78666