[Smt-talk] Irregular and Half Cadence

[Ninov, Dimitar N]

Dear Colleagues,

Thank you for providing nice historical descriptions of authentic/perfect cadence and half cadence. I want to address both terms with two additional references.

1. Concerning the term “irregular” as denoting “half cadence”, I wanted to remind ourselves about Rameau’s description of “irregular cadence” as II6/5 – I (Rameau-Gosset 1971, p. 74) which is an example of what one would call today a “plagal cadence”. While “irregular cadence” does not seem to have been widely used with this meaning, I wanted to point out the different directions “irregular” may have taken historically.

2. As for the half cadence, it is obvious that most sources that some of you cited refer to a close on the fifth degree. And that is only natural, for the half cadence on V is the most typical of all. Later on, in the same manner as we observe development of the term perfect (perfect=authentic; perfect =cadence that is harmonically and melodically perfect; imperfect as opposed to perfect, etc.) we start finding descriptions of the term half cadence that differ from the earliest ones. 

For instance, Rimsky Korsakov describes the half cadence as “stopping on a root position V or IV; in the former case it is an authentic half cadence, and in the latter – it is a plagal half-cadence” (Russian edition of Practical Manual of Harmony, lost front pages, p. 29).

For the plagal half cadence Rimsky gives the following two examples: I–IV and V–IV (this one in minor mode). While the second example may be interpreted as an interrupted cadence where IV takes the place of VI, one gets the general idea of stopping on S harmony.

In other words, terminology does develop and it is a good idea to keep an open mind in this regard, especially when we come across descriptions given by historical figures whose treatises and/or musical compositions have survived for so long.

Rimsky also shows how the interval of the augmented sixth affects the plagal cadence in the major mode. He gives the following resolutions as examples (I am providing the pop symbols first for more clarity: 

F7 (spelled as II6/5 with a raised root) – I ; 

Fm7 (spelled as II half-dim. 6/5 with a raised root) – I; 

B7b5 with F in the bass (spelled as VII half-dim.4/3 with a raised third) – I;

Fm7b5 with F in the bass (spelled as VII dim.4/3 with a raised third) – I;

It is also interesting that the leap of degree 4 to degree 1 in the bass creates plagal resolutions in the connection of the altered VII chords to tonic. Otherwise the last two chords would resolve stepwise to the tonic as linear dominant functions.

Thank you,

Dimitar

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