This applet does not play the sounds in Firefox. Safari and Chrome work fine - at least on laptops. I haven't been able to make the sounds play on my iPad at all.
red and blue sliders control fundamental frequencies of two different waves[br][br]dark gray sliders control amplitude of harmonics; light gray sliders control phase of harmonics; left column controls sound f; right side controls sound g[br][br]radio buttons at top control which waves are drawn