ToneGen PlusMinus

Signal generator for identifying audio frequencies by manually matching the pitch.

Identifying feedback frequencies rapidly and precisely as an audio tech in a concert situation is a crucial function. Sometimes the feedback is intermittent, or only happens for an instant. For decades I and others have used the procedure of holding a heard pitch in my head and them matching it with some sort of tone generator. There are several iPhone apps that I have used, holding the phone up to my ear to hear the tone. They all have either a dial or a slider to set the pitch. An endless dial can be very precise, but is difficult to operate without looking at the screen. A slider is resolution limited by the length on the screen and so can't be precise.

ToneGen PlusMinus uses a novel pitch setting UI which I invented 20 years ago for a Palm III app I wrote. It is very easy to rapidly and precisely match a frequency across it's range of 30 Hz to 10 kHz, without looking at the screen at all. The farther up or down from center your touch slides, the faster the pitch changes. Slide back to center and it stays stable.