The second movement of the "Moonlight" again: taking a really close "listen" to the opening triads yields a tremendous amount of information about consonance and dissonance on the piano.
It is hard for anyone trained in music theory to notice the subtle variation present here in the disposition of black and white keys, the various inversions, the octave placements of chord tones, etc.
Going over these sounds one by one was a fascinating exercise in how much trained musicians may miss in the pursuit of at least the illusion of ease with what we are playing.
It all started with noticing the actual sound of major triads on the piano: They are not all the same, nor are they interchangeable. Once having learned these notions it is very difficult, indeed, to face up to the reality of the sounds--a much more Beethovian requirement than any theoretical analysis will allow.
