> 220b: Synthesis Techniques, Compositional Algorithms, Psychoacoustics and Spatial Processing

## Homework 1 (due Thursday January 25, 11:59pm)

### Problem 1 (20 points)

The following block diagram (Figure 6.14 in the Computer Music Tutorial) shows a more elaborated FM instrument than the one seen in classes. Implement this instrument in SupeCollider.

Consider the following in your implementation:

1. You can make use of SynthDef if you want, but it's not mandatory for this first assignment.
2. Read the Env help file (inside SuperCollider) for the envelope implementations. In specific, take a look ad the .adsr and .triangle methods (they might come handy in your implementation).
3. If you need more details on modulation synthesis, read Chapter 6 of the Computer Music Tutorial

Your patch MUST output just one note, with the following specifications:

• Total note duration: 10 seconds
• Carrier Frequency: 440Hz
• Modulating Frequency (M): 75Hz
• Modulation index (I) envelope: [0.0, 13.0, 0.0] at times [0, 5, 10] seconds.
• Carrier envelope: [0.0, 1.0, 0.5, 0.5, 0.0] at times [0, 3, 5, 9, 10] seconds.

### Problem 2 (20 points)

In classes we saw an implementation for Steve Reich's "Piano Phase". Enhance this implementation in the following ways:

1. Both pianos start at the same time. Make the second piano start a number of measures later than the first. (e.g., 5 measures later). (hint: see the help file of Ptpar)
2. In the class implementation the piece goes on forever. Change this so that the piece makes just one cycle (i.e, makes the 12 transpositions) and stops when it comes back to the original transposition (both pianos in melodic synch)
3. Add amplitude envelope in the phasing process to make the phasing part more interesting. For example, add a triangle envelope to the accelerating piano (during the phasing process) to enhance the effect.
4. Change the phase duration (i.e, make it longer). Note that this doesn't mean changing the overall timing of the piece. You have to be careful in order that the two pianos come back to sync (rhythmic sinc) after the phasing period. Explain what and how you did it.