I personally don't see that there's any avoiding Vicentino and his archicembalo...

He certainly proposed using it to play in mean-tone intonation in any key, but also suggested adding chromatic elements to diatonic pieces and microtonal elements to chromatic pieces.

Now there's a project for some enterprising vocal ensemble...

Trouble is this Martle: your initial message #1 excluded at the outset what you termed 'different temperaments and the like'. Vicentino - and all other early theorists - always arrived at intervals less than a Minor Semitone by way of setting differing temperaments upon instruments of (thereafter) fixed pitch (fixed, that is, unless and until what had been set was then changed). Vicentino's archicembalo was an attempt to create an instrument accommodating all (by then) working temperaments (but this did not - incidentally - include Equal Temperament which at that time was limited to fretted string instruments).

Let's be clear: "Temperament" is a term that describes the way in which the prime intervals (3rds, 4ths, 5ths, and their compounds) are deliberately made impure within scientific levels of tolerance so as to enhance or enlarge the effects of changing key positions while minimising the grossly out-of-tune effects that would otherwise come into being.

Within this framework, microtones are what might be termed "coefficients of tempering", and in no way were conceived as being melodic entities. Now what I thought you were asking was something that involved melodic shading or colouration, and within the Equal Temperament system.

Baz

Er, Vicentino did in fact propose mixing the diatonic, chromatic and enharmonic 'genera' within a piece. If this works:



...you'll see the beginning of a madrigal. Unfortunately his sign to raise a note by a diesis is a little dot above the note - I suspect my scanner may have added some of those and taken others away...

Hm, no, having previewed it it seems to come through OK.

His suggestion to add chromaticism to diatonic pieces and enharmonicism (?) to chromatic pieces reads:

"...sè si agiogneranno à quelle de i Diesis Cromatici, & de gli Enarmonici fra i toni, & fra i semitoni; si sentirà gran utile di Armonia in quelle..."

Roughly: "if one were to add to these [compositions] some Sharps and Enharmonic Dieses between the tones and the semitones, one would hear a great gain of Harmony in them".