The Ultimate Tone Generator is a new iPhone app that lets you tune your instrument or "just annoy everyone in your vicinity".
TONE plays sine waves with frequencies from 7 Hz to 10,000 Hz. TONE also plays sawtooth, triangle and square waves based on additive formulas. These formulas only generate the lower harmonics of the real waves. The last waveform is called FM and involves a carrier and a modulator.
Using the waveform marked "FM", some new controls and displays will appear. The slider below FM Index will adjust the amount that the modulator modulates the sine wave carrier. A higher index will produce a brighter or harsher tone.
Pricing and Availability
The Ultimate Tone Generator is available as a free download in the App Store.