Beethoven isn’t Beethoven any more.

Slate has a great piece on why the piano we hear now ain’t the instrument great composers wrote on – and how that changes the best known tunes in history:

But music from the 18th and 19th centuries doesn’t just sound different now than on the original instruments; some of it can’t even be played as written on modern pianos. One example is the double-octave glissando in the last movement of Beethoven’s “Waldstein” Sonata. With the light action and shallow key dip of a period Viennese piano you can plant your thumb and little finger on the octave and slide to the left, and there it is. Given the much heavier action and deeper key dip of a modern piano, if you tried that today you’d dislocate something. Every pianist has a dodge for that passage. It’s said that before the glissando Rudolf Serkin would discreetly spit on his fingers.

The prime example of what I’m talking about is perhaps the most famous piece ever written: Beethoven’s “Moonlight” Sonata. Hector Berlioz called its murmuring, mournful first movement, “one of those poems that human language does not know how to interpret.” At the beginning, Beethoven directs the performer to hold down the sustain pedal through the whole first movement, so the strings are never damped. With the pianos of Beethoven’s time, on which the sustain of the strings was shorter than today, the effect was subtle, one harmony melting into another. On a modern piano, with its longer sustain, the effect of holding the pedal down would be a tonal traffic jam. Today you have to fake the effect, and it never quite works as intended.

You really owe it to yourself to check out the side-by-side audio comparisons in the story. It’s pretty whoah!