Temperament

Oh my god. Temperament regularly arouses heated passions and arguments among lutenists, especially on the lute mailing list. Intemperate is more like it. The arguments are futile because there is, mathematically, no right answer to the question of how different notes should be tuned relative to one another, so the different temperaments (tuning systems) are all flawed compromises. So it's largely a matter of which flawed compromise system you prefer, tinged with a little information about the systems used in the past.

Equal temperament (boo, hiss) is the modern standard. Mean temperament (1/5 comma, 1/6 comma, ...), just intonation, Pythagorean/ natural temperament, Valotti, Werckmeister, .... The debate rages. There are even i-phone applications for different historical tuning systems.

Refer elsewhere for more detailed explanations, for example Stuart Isacoff's book Temperament, aimed at non-specialist readers.

I'm not aware that the issue ever arises with modern guitarists. Firstly, fixed frets mean there's nothing to be done anyway. Secondly, guitarists seem to have accepted equal temperament long ago. Early nineteenth-century experiments with enharmonic guitars with crazy side-stepped fret dispositions gave impractical, not to mention unplayable, results.

On the lute, despite its movable frets, even the compromises have to be compromised. Each fret, as on the guitar, has to serve for five different notes. For example, the first fret on a G lute gives G#, C#, F#, A# and D#. Or, rather, ten different notes, since it also has to serve for Ab, Db, Gb, Bb and Eb. In systems other than equal temperament, these are not the same notes as the sharp equivalents. Which means, basically, that any tuning system other than equal temperament is shot to pieces.

A particular problem: Bb on the third course and F# on the fourth course require the first fret to be in different places. Both notes are frequently needed in the lute's favourite key of G minor. What to do? Some players have tried placing so-called tastini (little frets) just behind the real first fret, to allow both notes to be achieved. My own limited experience of tastini is that they are a serious impediment to accurate playing.

So, I'm with Vincentio Galilei (father of Galileo G) in advocating equal temperament. He put his theory into practice in his Libro d'intavolatura di liuto in 1584, with a mighty set of Passemezzos, Romanescas and Saltarellos, written in all the major and minor keys. This was a full century before the birth of J.S. Bach, he of the Well-Tempered Klavier. Various composers for baroque guitar (e.g. Bartolotti, Pellegrini) wrote similar cycles in the seventeenth century.

To be fair, I should allow the other side to put their case. Here are two well-written articles from Martin Shepherd and David van Ooijen. I'm not yet convinced, though...