Listening for Keys and Modulation

The major and minor modes can be said to differ from one another intrinsically, for in each mode the pitches form their own special set of intervals and interval relationships. As we have seen, C major and C minor, while sharing the same central or tonic pitch, have their own individual arrangements of half- and whole-step intervals.

Different keys, however, merely entail the same set of intervals moved to a new position within the pitch continuum. This is a significant difference, but not an intrinsic one. In baseball, first base is different from second base, but only because the same sort of bag has been put in a significant new place.

As for actually hearing keys — that is, recognizing the different keys — for some listeners this presents an even greater problem than hearing modality, though to others it comes more easily. The important thing is not to be able to identify keys in themselves, but rather to be able to hear when keys change. Changing the key of music changes its mood or the way it feels; generations of composers have used this resource for some of their most powerful effects. Such changes of key — that is, changes of the tonic or home pitch — are called modulations. You will have many opportunities to hear the effects modulations can create; here you should try Listening Exercise 7, the most challenging one yet, listening for changes in mode and key.