Being as it´s pretty difficult for guitarists to study Bach fugues, we need another approach. I have been digging deeper into 16th century lute music (although I´m starting late and probably won't catch up with any lute player), and there are an awful lot of good lute fugues, although they are usually constructed with sequential themes after the manner of a motet, and don't use the same techniques as Baroque fugues. Narvaez has some really nice ones with four voice entries at the modal nodes, although not with four sustained florid voices which is just plain too hard for six strings and four fingers. (Edit: I mean it is rare to find four florid voices together. There are lots of passages in four voice chords, note against note. When Luis MIlan wrote these passages he usually included a few parallel fifths and octaves just to thumb his nose at future pedants.)
I suggest that any guitar player who wants to study counterpoint should buy a cheap requinto and tune it like a lute and get into it. You can buy a perfectly good requinto for about 200 bucks USD, anywhere there is a pocket of Mexican cultural activity.
My new insight into composing fugue on the guitar is that it is very useful to confine the voices to their plagal and authentic ranges! This turns out to be a wonderful key to figuring out how to fit four voices onto the guitar, because it restricts the range to the gamut and takes away the question of "needing more range" than the guitar actually has. The guitar has more range than the gamut - if you can learn to restrict your four voices to the modal ranges and within the gamut (except for an additional f'' and g'' at the top, used by all lute composers), then the problem of range is removed entirely.
Typically the bass must be plagal, the tenor authentic, the alto plagal and the soprano authentic. Some of the soprano ranges - Lydian and Mixolydian - are theoretically truncated because they are beyond the gamut, but that didn't stop lute players from using those high notes, and composers had started to go beyond the gamut early in the 15th century anyway at both top and bottom.
Regarding Jeremiah´s comment - "So if some of the rules and guidelines seem esoteric, abstract, and pointless, keep in mind that a lot of the guidelines were developed to manage the restrictions of strictly vocal music. " I have this to say --
The marriage of species counterpoint and modal counterpoint was not made in heaven. Fux´s invocation of Palestrina (which occurs in his introduction) was strictly rhetorical (like invoking Orpheus or any number of classical Greek and Roman authors as was the custom), and it has been taken seriously by all authors since who, like Jeppesen, have led us all down a rabbit hole in search of the Authentic 16th Century Style in which to compose our species counterpoint exercises. It should become quickly apparent to any lute player that 16th century lute players did not follow the vocal style rules as taught in modern courses. Palestrina's style was an anomaly produced under the intense political pressure of the post-Tridentine Counter-Reformation, and most other 16th century composers and certainly most instrumental ones folllowed a far looser set of rules. I have compiled quite a list of "counterpoint errors" in various composers from Milan to Dowland -- parallel 5ths and 8ves, diminished fifths against the bass, cross relations which were much loved not only by Mudarra and Dowland, unsingable lines, and instrumental idioms which are certainly unsingable.
It is also notable that the modern books on modal counterpoint seem to all completely ignore the question of the mutation of the hexachords, which was the basis of 16th century chromaticism and really deserves a good look. The whole model of species counterpoint is twisted, in its modern form, towards the support of anachronistic 19th and 20th c. ideas of functional harmony - i.e., the Dorian mode equals the ii chord and so on. Also, the erasing by Jeppesen of the F-major Lydian and its replacement by C-Major Ionian appears to me to be another example of cherry-picking Renaissance theory for functional-harmony-friendly concepts, like the attribution of major and minor triads to Zarlino, who didn't quite say what he has been said to have said.
And just to beat up on species counterpoint a little more, let me point out that constructing cadences according to the models given in each species by Fux and his successors results in artificial cadences resembling almost nothing that any 16th c. composer actually wrote.
The simplest and most logical interpretations of the movements of species counterpoint will get the job done, and Fux himself did this quite well without loading us down with too many style rules. It is really hard to re-create a historical style, and at all times in history that I can identify that a historical style has been revived, it always comes in a new flavor. Trying to reproduce the style exactly is a pedantic exercise that seriously interferes with actual creative process. Sometime we have to get over it and just write some music the way we want to.
Maybe I will post more about this when I feel more confident of the subject!
Last edited by jack_cat on Sat Jun 13, 2015 8:49 pm, edited 1 time in total.