Over the preceding months I have been making a rather breakneck tour de force of the many temperaments used in Western music. For the most part, this has involved: first, exploring them theoretically in writings, recordings, and other media; second, applying them to non-historical instruments housed at the NMM (primarily a Wolf copy of the NMM's Germain harpsichord); and finally, transferring the decidedly "best" or "most appropriate" temperaments to various historical instruments on display throughout the museum.
More recently I have been spending a lot of time with the Pythagorean-Just-derived circular temperaments of Baroque western Europe: Werckmeister, Schlick, Vallotti, the preponderant "Bach" schemes, etc. The era of music and temperaments that most dominates the "historical performance" scene. Slowly approaching circular regularity a la equal temperament has been an interesting chronological adventure. Abandoning entirely the sweet purity of the major thirds, however, has been a painful, uphill struggle. Yes, there is a time, place, and piece for every temperament to shine. Yes, Bach's Well Tempered Clavier is a monumental masterpiece of Baroque fashion that both implores and is implored by an irregular, circular temperament. Yes, being able to play in every key with aurally passable results grants expounding freedom in composition. That being said, not a reason in the world can override the harmonically gravitational elephant in the room that is the pure major third.
Enter the French temperaments. Running contrary to the general continental trend, the French were as peculiar in their Baroque temperaments as they were in most other matters of art, life, love, and politics. Unlike the Pythagorean-comma splitting of the circular temperaments that Bach and his contemporaries founded their compositions upon, the French made every effort to remain true to the sanctity of the syntonic-comma meantone third. They arrived at circularity in a manner that preserved, at the least, three of the pure major thirds that make standard 1/4 syntonic comma meantone so gosh-darn hypnotic. The ear-grating "wolf" fifth of the meantone temperaments (the Diesis) was split between a number of its neighbors, eventually resulting in a remarkable temperament — fully circular, albeit irregular, with no wolf and the qualities of 1/4s.c. meantone faithfully preserved in the central diatonic keys. The Tempérament Ordinaire.
Today I made my first practical foray into coaxing a full instrument into the ordinaire. Using the beat-rate scheme from Di Veroli's Unequal Temperaments I partitioned out the lower 8' on the Wolf from c' and shortly after filled in the full compass. It felt a bit sacrilegious de-tuning the wonderful, nearly equal Barnes temperament I had set last week, and reverting to narrowly tempered fifths from the many pure (or close to) ones took some minor re-acclamation, but in the end it seemed well-justified.
Pure thirds. Oh how I have missed their sublime tranquility. And now I have them back, in a circular temperament no less. Obviously the practicality of the ordinaire depends entirely on your repertoire and expectations—it would never work for Bach—but for the noodling I so often do, it seems to present a presently ideal balance between the beauty of meantone and the functionality of the Pythagorean-Just circular temperaments. Sure, the distant keys are less consonant than Valotti would deem acceptable, but they are useable, and that is more than good enough in many, many cases.
I took a short video with my phone of a random French-repertoire excerpt. I cannot recall offhand what it was, so feel free to let me know if you recognize it.