Yesterday I saw an old film featuring splendid harpsichord and organ playing by Gustav Leonhardt along with other fine period instrument players, in a rather badly strung-together film called The Chronicle of Anna Magdalena Bach (a total fiction--just an excuse for filming settings and various kinds of Bach compositions). The film was preluded, so to speak, by the theatre (a non-commercial artsy, film-buffs' hangout) playing a non-stop CD of the Well Tempered Clavier on a modern piano. I cringed in anticipation of the horrible impact of the first sounds on a harpsichord appropriately tuned, i.e., not in equal temperament. The whole point of that other tuning is how IN-tune it is. Relentlessly playing equally tempered recordings beforehand produced the opposite effect. By the end of the film one had adapted, of course; but the whole point was lost.

I play the modern piano. I love the sound of the modern piano. It is magical and wondrously open-ended.

I love also the sound of the harpsichord appropriately tuned in some version of mean-tone temperament, in which the major thirds are gentle and chromatic intervals full of character.

Each is, in its way, splendid. But they are not interchangeable.