I know about the difference between authentic and plagal modes, theory
wise, ever since I was in high school...however I am still confused about
them when it comes to organ pieces.

I look up at all the compositions from Ireneo Fuser's book of Classical
Italiani Dell'Organo, and there are plenty of intonazioni or toccate or
ricercari that were composed according to mode..ie. I tono, II tono, IV
tono, XI tono, and even F major (XI Tono detto Quinto).

I compared the difference between the authentic and the plagal
compositions that are of the same pair (I vs II, XI vs XII, etc.), and
there seemed to have no differences whatsoever.  They both end on the
same final, but I cannot find any traces of the reciting tones, which are
one of the differences between authentic and plagal, theory wise.  I
also cannot find any traces of the original hymn or chant on which a
composition supposedly based, so that makes finding the reciting tone
even more difficult.   Can someone points out how I can differentiate the
authentic from the plagal in an organ composition, especially in the
comparatively free form of toccata or intonazione?

On a sidenote, I thought most elevazioni should be written in mode III,
ie, the "mystic" Phrygian mode.  But I found examples, such as
Frescobaldi, wrote in mode IX.  I thought perhaps it is a case of a III
Tono detto Quinto, but I cannot tell since most of the Bs in the piece is
not flatted, nor was there a key signature of one flat.

Finally, can someone explain to me why many of these compositions,
especially intonazioni, end in a major triad chord (raised third)?  Isn't
that defeat the purpose of establishing a mode?  Or is it the case where the
function of the composition has nothing to do with establishing the mode,
but rather as a tuning piece for the choir or priest to know which note to
start their chants, since a lot of people do not have perfect pitch?  But
other compositions such as the toccate and the ricercari also have the
raised third.  Some from the composer, some from the editor.

It feels weird for me because I have studied Italian organ pieces for a
very long time, and suddenly today it dawned on me that I never quite
understand these problems.  I guess a lot of times I enjoy playing the
pieces and never thought about the theory.  Also I think most people who
do analysis on pieces only concentrate on the more complex work like a
Canzona, a Fugue or a Ricercar: many ricercari do not base on modes.

I hope this is not out of topic...I love playing Marc Cavazzoni on my
Virginal...it is perfect.  Perhaps questions like these differentiate
between an organist from a harpsichordist..



 --
Vincent B. Ho  [log in to unmask]

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