It turns out that, late in life, Beethoven got ahold of the newly-invented metronome and marked up all eight of the symphonies he'd written up to that point to show what speed they shd be played at -- that is, how many beats per minute. No longer did he have to rely on vague descriptors like "allegro" and "adagio" ; instead he cd mark the beat exactly as if he were conducting it.
You'd think that, for those interested in a composer from pre-recording days, who had only sheet music to preserve his music, this wd be a godsend. Except that it turns out performances of Beethoven's works routinely ignore his directions because they think it makes the music sound too fast. The Radio Lab segment explored various arguments folks have used to explain away the markings (B's metronome was broken, there were transcription errors, his deafness prevented his recognizing a false tempo) and ended by suggesting that Beethoven wanted his music to sound edgy, and so deliberately avoided the grand, stately measures which we've come to associate with him. They ended by having a string quartet play a bit from The Fifth at Beethoven's tempo, and then trump this by playing at even faster rates; by the end they gotten to something truly fascinating that sounded like a cross between Rimsky-Korsakov's "Flight of the Bumblebees" and the theme music from the old Jeremy Brett SHERLOCK HOLMES series. Here's the link.
If you want to just hear the Beethoven, here's a link to a stripped-down version of the segment, with just two examples of the music but showing the actual musicians, so it's worth checking out.
One nice added feature of this second link is that it includes a listing not in the original, in which they went out and compared various recordings and, not surprisingly, found that most played the Fifth too slowly. Ironically, the one recording that got it right -- that is, played Beethoven's Fifth at exactly the speed Beethoven wanted -- is Walker Murphy's A FIFTH OF BEETHOVEN . Guess I'll have to dig out my old (vinyl) record and give it a listen; it's been a while.
The thing that interested me most about this is that, if they're right, it means Beethoven suffers from exactly the opposite problem as that which bedevils Scott Joplin. People play Beethoven too slowly and stately, and they play Joplin's ragtime (which was intended to be dance music) too fast. At least recordings of Joplin at the proper speed are available (e.g., in Joshua Rifkin's excellent cd, or in a piano roll from Joplin himself.* Now to see if I can find a whole symphony of L.v.B. at fast tempo.