Spektar Design Lab comes with a few examples.
A great example of an audio effect, reverb implementation design is available in examples/reverb.xml. This is a slightly modified implementation of Schroeder reverb with some practical I/O setup.
Notable practical additions are wet and dry bench controls, output filters, and modulation in comb and all-pass filters which substantially increases percieved reverb quality.
Reference: M. R. Schroeder and B. F. Logan, ``Colorless artificial reverberation,’’ Journal of the Audio Engineering Society, vol. 9, pp. 192-197, July 1961.
As an example of sound synthesis, we have a simplest, single oscillator, monophonic synthesizer.
Though simple, this synth can make some cool sounds. Setting the oscillator to SQU (square wave) and triggering in low octaves makes some great growling bass stereo sounds. In mid/higher octaves, SIN setting can make some nice flute-like sounds.
As an example, this synth doesn’t include bench controls other than the keyboard.
Now proceed to the concepts.