Many years ago I went through a mad Rachmaninoff phase -- who doesn't? -- and decided to learn to play the "Prelude in C Sharp Minor". At the time (I was a teenager) I had no idea just how clumsy and bombastic my interpretation of this wonderful piece was. Here's how it is supposed to be played -- a performance by the composer himself. The beginning, which I had always thought was dark and ominous [I sort of imagined Boris Karloff playing it] is actually rather light and delicate. Who knew? I sure didn't.
Here you go -- Rachmaninoff plays Rachmaninoff.
