I590/N564/N364 Additive Synthesis Assignment

I590/N564/N364 Additive Synthesis and Timbre Assignment

Donald Byrd, rev. 19 Feb. 2008

This assignment requires John Gibson's little Max/MSP program "addsynenv". addsynenv runs on a Macintosh computer with OS X. I tried a machine with OS 10.2.8, and it didn't work, but it's fine on OS 10.4.x machines. (You can use the Macs in the STC on the third floor of the Music Library for this assignment.)

If you're going to use one of the Music Library computers, you'll need headphones with a 1/4-in. plug to hear anything; you can get a set at the Circulation Desk.

1. Download addsynenv_archive.zip, resulting in a file called addsynenv_archive. Open addsynenv_archive to produce addsynenv itself (it has a weird-looking icon suggesting a sonogram).

2. Launch addsynenv. You should now see its (somewhat familiar) window, with information about the partials and little frames for their envelopes, etc.

3. Get the documentation on addsynenv from addsynenv_usage.txt.

4. (Q1a) Say in writing: why does the "Scary" preset start out as a pure tone, then start wavering more and more? (b) About how wide a pitch range (in semitones) is it from the lowest partial to the highest?

5. The "Whole-tone" preset -- while it sounds like a single note -- also gives the impression of a rapid ascending whole-tone scale, followed by a rapid descending whole-tone scale. (Q2) Why? Be specific. (If you've forgotten what a whole-tone scale scale is, there's a definition, with an example in both CWMN and audio form, in the Virginia Tech Multimedia Music Dictionary.)

6. Modify the whole-tone preset so it "plays" only the first three ascending notes, but so you can hear those three more clearly. I recommend starting by (a) in the last three partials, deleting all breakpoints but the first and last (so each has an envelope consisting of a straight line at the bottom of the window); then (b) dragging existing breakpoints in each of the first three. Tip: if you get too confused, you can start over simply by clicking another preset, then clicking again on the whole-tone preset! (Q3) So I can see what you did, take a screenshot by pressing shift-command-3. This will create a file called Picture 1.png on the desktop; print it out. (I don't care if the spectro/sonogram area is in the printout, but please be sure everything else is.) For extra credit, create an audio file of your sound and get it to me by (or in) class. (I don't know if it's even possible to record internally with the STC computers, but I'd like to! Of course you could always record the sound coming out of the speaker or headphone, or, better, the signal coming out of the audio/headphone jack.)

7. (Q4) In the sonogram, what color shows a frequency has low amplitude? What color shows medium amplitude? What color shows high amplitude?

8. (Q5) Which of the presets have partials that aren't harmonics? List them by name.

9. Bring the printout for Q3 and written answers to Q1a and b, Q2, Q4, and Q5 to class to turn in.