Chaconne in Dm Buxtehude (1638-1707)
“We Gather Together”
The idea of building a piece on a repeating pattern (eight bars long, say) has been around since time immemorial. Baroque era versions of that would be the "passacaglica" and the "chaconne" ("shah-CONE"). Two modern applications of that idea would be Taizé (a Christian meditative musical form) and Rap.
Now I’m no fan of Rap, but in its defense may I suggest: music generally has ’foreground’ elements to which you are really supposed to pay attention, and ’background’ elements that support the foreground. In a jazz combo, ferinstance, the drummer is generally a background element that helps the whole ensemble hold together (except when the drummer gets to be ’foreground’ in drum solos). So my problem with Rap in general is not with the musical form itself (since that’s not really what that music is about), but the messages it generally tries to convey in the lyrics.
In the case of DNA the ’carrier’ is the strand of four possible nucleotides, the ’signal’ would be the particular sequence.
This is also analogous to the idea of ’information’ and ’carrier’ in radio (and TV) transmissions. In radio transmissions you have a ’carrier’ — a constant signal, which is modulated to convey the information. In the case of Amplitude Modulation (AM radio), the carrier is the constant frequency to which you tune your radio, and the ’information’ — the music or commercial for "Spatula City" or whatever — is conveyed by changing the amplitude — the loudness of that signal.
I suppose you could say we are all ’radio transmitters’ in that each of us is given a relatively constant ’carrier’ — life itself: breathing, heartbeat, brainwaves, etc. — and the opportunity to ’modulate’ that ’life carrier’ to broadcast whatever message we want to our fellow humans and the universe at large. Hitler chose to broadcast one message, and Mother Theresa quite another.
Wow, how did I get so far afield from passacaglicas and chaconnes? Sorry, one moment please while I pull myself together… There… (ahem, ahem…) So… where was I?… oh,… right…
The ’passacaglia’ and ’chaconne’ are both forms based on the idea of a repeating bass or harmony pattern — generally eight bars long, and generally in 3/4 time (three beats to a measure — like a waltz). Buxtehude was one of J.S. Bach’s ’heroes’, and in this morning’s chaconne I think we can hear why.