Just kidding about the Elliott Carter bit.
But I did realize something great today: there's an out-of-nowhere metric modulation in the Lionel Richie song "Say You, Say Me" (here's another totally rad movie montage video for an Oscar-nominated song from a Taylor Hackford directed flick from the 80's--see this). Isabella is SO PRETTY.
I digress. I never thought much about the tempo change. Figured the bridge was just...faster. Not metrically related to the original tempo in any way. But I heard the song today and had one of those "Wait a minute..." things that keeps me from doing anything at all productive until I find the answer. Sure enough, I was right.
Here's what happens at the transition into the bridge:
To clarify--the single eighth note triplet "becomes" the eighth note, increasing the tempo by 1/3. I found sheet music online that uses this notation:
compound meter--it's 4/4 moving to a faster 4/4. I need information that will help me count the NEW tempo. If I didn't know the song and was trying to figure out this tempo shift, the dotted quarter is just confusing. True, telling me what the "new quarter" is in relation to the old tempo is tricky, but the triplet eighth/new duplet eighth relationship is a piece of cake.
The bridge is short and transitions back to the old tempo suddenly and rather awkwardly. It is, in fact, not a very good bridge. The song as a whole is pretty pedestrian. But Lionel Richie is cool as hell. And I give him (or producer X) credit for this very unusual metric modulation trick in an otherwise pretty half-assed ballad (He had a dream! He had an awesome dream! You are a shining star!).
I still love you, Lionel. "Dancing On the Ceiling" makes up for this and then some. And don't get me started on "Easy." AWWWWWWWWWWWWWWWWW shit.