Many non-musicians—and some musicians, too—are under the impression that something is either "in tune" or not in tune. This is not, strictly speaking, a true representation of how music in the West works. Nature does not have a perfect, quantifiable tuning system; every time something is put "naturally" in tune (i.e., according to the acoustical properties one would find in a specific natural environment), something else suffers, and sometimes spectacularly so. Though there are various "just" tuning systems (systems which contain pure tuning throughout), each one has properties which prove to be trouble for certain repertoire. As music in the West began to become more and more chromatic, just tuning became more problematic. The solution musicians have long used for dealing with tuning issues is temperament (tuning compromises). Because of all of this, something is not, in fact, "in tune" or not in tune; rather it is "in tune" only within the confines of its own system.

When people speak of something as being "in tune" these days, they almost invariably are speaking of the compromise known as "Equal Temperament." Equal temperament has been ubiquitous for so long that we sometimes forget just how much tempering (compromising) is involved in this system. In my lectures, the only comparison I can make is to the psychological syndrome of the "folie en famille"—a shared madness. In essence, when everyone around you is crazy, nobody seems particularly odd. Similarly, when all of the intervals around you are equally out of tune, nothing seems out of tune.

The eventual emergence of tonality in the Baroque, and the resultant advent of keys, did not coincide with the dominance of equal temperament as the preeminent tuning system. Indeed, the other systems had too much to offer to be flippantly abandoned. Simply put (perhaps too simply put), each key had its own collection of associated affective qualities which composers could exploit. (Though said in the context of a famous joke, Nigel Tufnel was not far off, historically speaking, when he deemed D minor, "the saddest of all keys.") On this fascinating recording, pianist Enid Katahn and her team of acoustic advisers bring to life not only some well-known repertoire works, but also the tuning systems that may have been used at the time in which some (not all) of the pieces were first performed. Perhaps the most interesting part of the recording is the "temperament comparison" section of the disc, in which Katahn plays Mozart's transcendental D minor fantasy in three different temperaments: Equal; Prelleur, 1731; and 1/4 Comma Meantone. This last one, which favors just thirds, but also creates several wolf tones (in temperament, noticeably out-of-tune sounds), is sampled in this month's clip. The expressive nature of this tuning system turns downright crunchy at times, and I doubt that even non-musicians will fail to notice the difference in the applied chord in the second half of the eighth measure.