My research into Mozart's soundworld is leading to some very interesting and unexpected discoveries. I have suspected a connection between the natural horn and his sense of tonality, particularly minor keys. I suspected also a strong connection between the horn and his sense of vocal line. Then I found an essay by Paul Bryan about Mozart and Haydn's use of the horn. It mentions specific numbers in Mozart operas in which the horns figure prominently and with unique power.

Eager to hear this I wondered if there could possibly be a period-instrument recording of Idomeneo, the opera cited as making rich use of this instrumentation?

To my surprise, there is. Harmonia mundi has released a three-CD set of the opera with the Freiburger Barockorchester. Wonderful, thought I!

Actually less than wonderful.

The voices are superb--alive, wonderfully present in the force of their characters. But the instruments I find completely lacking in color, producing harmonies that have been subjected to modern homogenization. So why use period instruments?