IADSPL : Sound Synthesis (continued) (page 26)

Synthesis (continued)

Now for something a little more compilcated:

		octave:1> h0 = sinegen (44100, 44100, 440) ;
		octave:2> h0 = h0 .* ad (44100, 5000) ;
		octave:3> h1 = sinegen (44100, 44100, 440*3.01) ;
		octave:4> h1 = h1 .* adsr (44100, 2000, 8000, 0.2, 5000) ;
		octave:5> h2 = sinegen (44100, 44100, 440*5) ;
		octave:6> h2 = h2 .* adsr (44100, 100, 5000, 0.1, 4000) ;
		octave:7> h3 = sinegen (44100, 44100, 440*7.01,001) ;
		octave:8> h3 = h3 .* ad (44100, 200) ;
		octave:9> sig = h0 + h1 + h2 + h3 ;

This is what is called additive synthesis. For most interesting sounds additive synthesis will require many more components than just the four used in this example.

Another common synthesis technique is subtractive synthesis where we start with waveform with many sine components and subtract stuff out of it using a filter.