Science Fare

For fun I thought I’d try composing some rhythms following these rules:

• each phrase consists of a #notes in the Fibonacci sequence (1,1,2,3,5,8,13,21,etc…)
• If the #notes / #measures in the phrase > 8 then increase the # measures by a factor of 4
• Simplicity

Here is my first crack:

Lilypond Source

Today I came to my lesson not quite prepared. I confessed as much, but presented four new reeds for inspection as apology. Thus we ended up spending the whole time on reeds.

One insight was that scraping a reed makes the pitch flatter (lower). You may recall in an earlier post that a “C” pitched whistle blown with humid 100°C air should be 4.3 cm. An oboe reed is typically 6.9-7.1 cm. The realization I had tonight was that (duh!) the reed is contributing to the vibration. Obviously I understood that the reed was responsible for tone generation, but the mass and springiness of the cane also influences the pitch. Much like how heavier or more taught strings have different pitch on a stringed instrument (even though the length is the same). The fascinating thing is that the oboe is a hybrid between a vibrating stick (like a marimba bar) and a whistle (like a flute). It is probably because of this hybrid nature that the instrument is so unique in its sound (and fussy to play).

Alas all four reeds leak. I could detect it only on a few of them, but Carrie assured me they all were flawed this way. She gave me a few pieces of cane that she’d gauged for comparison. I might have a problem with my tying or shaping which is causing the leaks… alas.

The basic process of refining a reed is like this: (This is the work flat and easy method. Tabuteau worked the other way — sharp and hard. His method was probably better? But we’ll stick with the flat&easy for now.)

Start with mainly the tip, which starts on the sides 20mm from the end of the string (which should also be the end of the staple). In the center of the reed, the tip will be further up, maybe 21mm. Focus primarily on the corners and sides, until the reed blows nice and easy a single “C” crow. She didn’t say as much, but I assume it’s okay to rough in the back a little as you do this. Now work on the blend between the tip and the heart until the crow sounds the C octave. If it chatters or warbles, then thin the sides of the tip (the region about 1mm wide the full length of the tip). Once you have a crow, continually monitor the pitch, as you are scraping it will go flat. Clip it to bring it back to “C”. As you clip, it will get harder to play. Scrape it to make it easier to play, but scraping also lowers the pitch. So, clip to get back to “C”. As you scrape the tip to make it easier to crow, the balance between tip and heart will go out of whack, so you’ll have to thin the blend and heart to get crow to sound the C octave. You’ll be flat again, so clip to get back to “C”. etc… as you see it is a round-and-round affair as every time you make an adjustment for ease of playing or stability, the pitch alters requiring you to clip, which alters ease and stability…

Clipping is tedious. You can pin one edge of a very sharp razor blade to the block, then maneuver the reed under it until almost nothing is showing of it. Squashing the reed shut as you do this helps, as that way you’re not aligning it in 3-D. Then with a scissor motion clip a minuscule amount. The width of a hair is too much — that’d probably raise the pitch from a “A” to a “C” all at once. Generally you’re only trying to go from a “B” to a “C”. So 1/3rd of a human hair is about right.

I’m being summoned for the dog walk now.

Today I performed with Jeff Sass at his church up in the North metro. While we struggled a little on the Bach two-part invention, the Tchaikovsky waltz turned out quite well. Give it a listen.

I’ve also created a new “podcast” stream for recordings of my performances. I’ll try to update it whenever I have something new that’s maybe worth a listen. Simply copy this URL and paste it into iTunes under Advanced -> Subscribe to Podcast :

http://blog.paddlefish.net/music/feed.xml

Up next: Kenwood symphony concert in two hours.

Here is today’s concert. You can download directly into iTunes by adding this URL as a podcast:
http://blog.paddlefish.net/music/hso_may_2009/feed.xml
… or just listen by downloading from here. Mom, you can hear me in the opening bars of the Barber of Seville, and near 4:30 + 5:00 + 5:40 in the Brahms. The balance is really odd — probably because my mic was concealed in a planted shrub.

Listen to the Andean Flute performance from this afternoon in iTunes or download directly here:

Zamphir, eat your heart out.