Friday, February 29, 2008

Swan Loop

A few posts ago, I suggested that listening to a 24-second Tchaikovsky loop for 45 minutes had done me no harm. Well . . . it now seems possible that I'm stuck in my own strange loop in which each blog entry will just be a return to the same topic. At least that might solve the annoying blogger's block problem. Anyway, if this is the beginning of my descent into madness, so be it.

Whither today? After linking to the Wikipedia article on Strange Loops, I actually read it myself and discovered the Shepard Tone Scale. This is sort of like a barbershop pole of sound: tones continually ascend (or descend) in multiple octaves, fading out at the top as new ones fade in from below. Thus, there is continuous directional motion, but the mass of sound never really goes anywhere. I was intrigued to learn about this, because I'd used a similar principle in looping Tchaikovsky's Nutcracker sequence. Each time the sequence starts in a new octave, I wanted to restart it an octave below, but to smooth the transition, I faded the violins back into the violas. I intentionally did this after the sequence starts up again in the upper octave to make the switch less obvious; thus, you hear the last three pitches below (which are the same as the first three) resolve to the expected E, which maps onto the E in the first complete measure; the fade takes place going into the second complete measure.

So, I was proud to have discovered this technique on my own, and I also couldn't resist the temptation to explore it at greater length. First of all, here's an example of a Shepard-Risset Glissando (found here). Cool, but spooky. I thought I'd just try it out on some scales, so I enlisted the aid of the tiny little cellist inside my computer to create the following:

G Major Scale

Whole-Tone Scale

In each case, kind of like with one of those magic-eye pictures, the illusion works best depending on how you listen. I found that by focusing on a single scale as it ascends, one gets the best effect. Still, these aren't very interesting musically. My next step was to feature the same little cellist in the opening of The Swan.* It doesn't work as well as it might if I invested hundreds more hours, but you can get the idea by clicking on the gliding swan below. Wait a minute! Swans? Tchaikovsky? How could I possibly resist what comes next?

True, this isn't so much about a looping sequence as it is manipulating what happens in countless melodies where a phrase seems to be repeating itself, but then goes in a different direction. Or not, in this case. Props to Maestro Köhler for keeping the tempo steady, and to the anonymous oboist of the National-Philharmonic Symphony who just keeps spinning out beautiful tone. (I'll bet other oboists are jealous.) This is one of my favorite melodies of all time, and I always enjoy the buildup more than the slightly crass entrance of the brass that follows. Problem solved . . . at least until that swan develops an attitude.

By the way, having entered the world of Escher-type animations, I got a kick out discovering this one.

* I know, computer cello? But it sounds better than me playing this game, which I could master just fine if my mouse would cooperate. Hat tip to Elaine Fine for pointing to the game, which is actually quite cool.

No comments: