Tone Generator - Metronome

Metronome(tone generate) is a device that produces an audible click or other sound at a regular interval that can be set by the user, typically in beats per minute (BPM). Metronomes may include synchronized visual motion. Musicians use the device to practise playing to a regular pulse. 
Musicians practise with metronomes to improve their timing, especially the ability to stick to a regular tempo. Metronome practice helps internalize a clear sense of timing and tempo. Composers and conductors often use a metronome as a standard tempo reference—and may play, sing, or conduct to the metronome. 
The metronome is used by composers to derive beats per minute if they want to indicate that in a composition. Conductors use a metronome to note their preferred tempo in each section.
This app contain three types of metronome or tone generator. The first is more complete with a lot of musical tones. Second and third are more simple if you need only a tempo reference.
How to use your App?
A tempo marking is a term that conveys a narrow range of tempos and an associated character. For example, the term "Vivace" can indicate a tempo between 156 and 176 BPM, but it also communicates that the music should be played with a lively character. Metronomes will often include both BPM and tempo markings.
Metronome's tempo typically is adjustable from 40 to 208 BPM. The most common arrangement of tempos on a Maelzel metronome begins with at 40 beats per minute
and increases by 2s: 40 42 44 46 48 50 52 54 56 58 60
then by 3s: 63 66 69 72
then by 4s: 72 76 80 84 88 92 96 100 104 108 112 116 120
then by 6s: 126 132 138 144
then by 8s: 144 152 160 168 176 184 192 200 208. Some digital metronomes allow adjustment to more precise tempos (e.g. increasing 120 to 121), but such a difference is hardly perceptible.