{"id":118,"date":"2021-02-09T11:02:00","date_gmt":"2021-02-09T16:02:00","guid":{"rendered":"https:\/\/courses.ideate.cmu.edu\/15-322\/s2021\/?p=118"},"modified":"2021-04-06T10:52:50","modified_gmt":"2021-04-06T14:52:50","slug":"project-2","status":"publish","type":"post","link":"https:\/\/courses.ideate.cmu.edu\/15-322\/s2021\/project-2\/","title":{"rendered":"Project 2"},"content":{"rendered":"

Deadlines:
\nDue 11:59 pm Eastern on February 22 2021.
\nPeer grading due 11:59 pm Eastern on March 1, 2021.<\/strong><\/p>\n

Download<\/h1>\n

P2.zip<\/code><\/a><\/p>\n

Envelopes<\/h1>\n

Envelopes are very important in sound synthesis. Envelopes are the primary way to “shape” sounds from various sound sources so that the sounds do not suddenly pop on and off or blast at a constant level.<\/p>\n

You should have learned to use both “pwl” and “env” for envelopes in the on-line lessons. Hint: Look up “pwl” and “env” in the Nyquist Reference Manual and pay attention to their behaviors under different stretch environments.<\/p>\n

Composition Programming<\/h1>\n

The following code creates a short score and plays it when you click the “F2” button in the Nyquist IDE (maybe your keyboard F2 key will work too):<\/p>\n

variable *ascore* =\n      {{0 1 {note pitch: c2 vel: 50}}\n       {1 0.3 {note pitch: d2 vel: 70}}\n       {1.2 0.3 {note pitch: f2 vel: 90}}\n       {1.4 0.3 {note pitch: g2 vel: 110}}\n       {1.6 0.3 {note pitch: a2 vel: 127}}\n       {1.8 2 {note pitch: g2 vel: 100}}\n       {3.5 2 {note pitch: d2 vel: 30}}\n       {3.7 2 {note pitch: d4 vel: 70}}\n       {3.9 2 {note pitch: d5 vel: 70}}\n       {4.1 2 {note pitch: d6 vel: 50}}\n       {4.9 0.5 {note pitch: g4 vel: 40}}\n       {5.2 2.5 {note pitch: a4 vel: 30}}}\n    \nfunction f2() play timed-seq(*ascore*)\n\nvariable *bscore* ; to be initialized from *ascore*\n\nfunction f3() play timed-seq(*bscore*)\n<\/pre>\n
Create a file named instr.sal<\/code>, paste this code in, and try it.<\/p>\n
Define an Instrument<\/h2>\n
Your first task is to define a new instrument, also in the file instr.sal<\/code>, that multiplies the output of a table-lookup oscillator by an envelope. The instrument should consist of<\/p>\n
    \n
  1. a table created as shown in the lectures using the build-harmonic<\/code> function and containing at least 8 harmonics,<\/li>\n
  2. an oscillator (use osc<\/code>), and<\/li>\n
  3. an envelope.<\/li>\n<\/ol>\n
    The instrument should be encapsulated in a function named simple-note<\/code><\/b> that at least has the two keyword parameters seen in *ascore*<\/code> (pitch:<\/code> and vel:<\/code>). The vel:<\/code> parameter represents velocity, a loudness control based on MIDI key velocity which ranges from 1 to 127. Convert MIDI key velocity to amplitude using the vel-to-linear<\/code> function (see the Nyquist Reference Manual). Your simple-note<\/code> instrument function should satisfy these requirements:<\/p>\n