Assignment 4 is to make a qlist-driven polyphonic instrument that plays a simple sequence. There are many ways to do this. I did something simple and made the synthesizer just play sinusoids. What follows is what I did:

• Grab the "D07.additive.pd" example from the documentation (for you mac users, you have to "open package contents" on the Pd app and look in Contents/Resources/doc/3.audio.examples. On PC, it's just Pd/doc/...) Grab both the example (but rename it to avoid confusion) and the "partial.pd" and "output.pd" abstractions it needs. Put these in a new folder.
• Alter the "partial" abstraction (which I renamed "voice" to reduce confusion), so that it has an inlet to trigger it instead of receiving the global "trigger". Then make four copies of the abstraction. (I gave them arguments 1 1 1 0 so they would play the original pitch specified.) Now the situation is that "frequency" and "duration" are sent globally to all four, but each one is triggered separately.
• Make a "receive n" ("n" is just the name which is arbitrary but should agree with the qlist contents below). I designed it simply to take a MIDI pitch, a single number, as a message to play a note at that pitch. When "n" gets a number you have to allocate a voice for it to play (among the four voices you made above). To do this, convert the pitch to MIDI, send it to frequency, send something reasonable (like 40) to "duration" (which the abstraction still needs unless you've changed that). After sending these two messages, send a bang to a counter (using the objects "f", "+ 1", and "mod 4"), and then use a "select" object to distribute bangs to the four voices in turn accorsding to the number.
• Make a qlist object and make it read a file with a sequence such as:

  n 67;
  350 n 71;
  350 n 74;
  700 n 67;
  n 71;
  n 74
  

  This is a dorky-sounding doorbell; the musically minded among you might want to put in your own more artistic sequence.
• Start the qlist and enjoy the music.

There are many, many possible improvements you could make on this. It might be better to have the qlist specify durations note by note. You might also want to make a smarter voice allocation scheme than just counting through the four voices. Yu'll probably want to make a spiffier sound which will then need more parameters. You might want to send the parameters via messages to the voices instead of just sending them everywhere globally. Etc...