Tutorials and Topics - Peabody Computer Music

Tutorial 2: Fundamentals—Adjustable oscillatorAmplifier: *~A signal you want to listen to—a signal you send to dac~—must be in the amplitude rangefrom -1.0 to +1.0. Any values exceeding those bounds will be clipped off by dac~ (i.e.sharply limited to 1 or -1). This will cause (in most cases pretty objectionable) distortionof the sound. Some objects, such as cycle~, output values in that same range by default.The default output of cycle~ has amplitude of 1To control the level of a signal you simply multiply each sample by a scaling factor. Forexample, to halve the amplitude of a signal you simply multiply it by 0.5. (Although itwould be mathematically equivalent to divide the amplitude of the signal by 2,multiplication is a more efficient computation procedure than division.Amplitude adjusted by multiplicationIf we wish to change the amplitude of a signal continuously over time, we can supply achanging signal in the right inlet of *~. By continuously changing the value in the rightinlet of *~, we can fade the sound in or out, create a crescendo or diminuendo effect, etc.However, a sudden drastic change in amplitude would cause a discontinuity in the signal,which would be heard as a noisy click.62