Notes for Lab 4: FM Synthesis of Instrument Sounds

Announcements:

• If you are having trouble sending the files to Jimmy in email, please make them available online and send Jimmy a link.
• Some constants to use:
  • phi_m = phi_c = -pi/2;
  • for bell: A_0 = 1
• Clarinet Lab: In place of Aenv and Ienv as arguments to clarinet(), use A0 and I0, which should just multiply the envelopes that you produce using the instructions in the lab.

Common Problems and Fixes:

• If you don't have specgram, install the SignalProcessingToolbox for Matlab, in \\Stuapp\NETAPPS\ under Matlab (the PLP key that it asks for is in \\Stuapp\Licences\ under Matlab.

  After installing the toolbox, make sure that the DSPFIRST directory is still in your Matlab path.

• Clarinet Lab: In the example for plotting woodwenv(), replace delta with 0.
• Clarinet Lab: Index exceeding matrix dimensions when using woodwenv
  woodwenv has one fewer elements than would usually be expected, so you have to scale other vectors that you use with it (say, multiplying it) down to its length. For example, to plot y1 from woodwenv vs. tt, use plot(tt(1:length(y1), y1).

Deliverables:

• Do one of the sound synthesis lab parts in Lab B (either the bell or the clarinet).
• Do all 6 parts on page 451 (the last part of the bell lab) for either instrument, for one set of parameters (one note -- pick your favorite). Use wavwrite to save the sound you hear.
• For each parameter to your final function (bell or clarinet), describe and show, with an example, what the paramter controls.
  • For the bell lab, answer the question separately for fc and fm.