In acoustics, a beat is interference between two sounds of slightly different frequencies, perceived as periodic variations in volume whose rate is the difference between the two frequencies. With tuning instruments that can produce sustained tones, beats can readily be recognized. Tuning two instruments are being tuned one might notice present a peculiar effect: when the two tones are close in pitch but not identical, the difference in frequency generates the beating.

Directions:(Works Best using CHROME Browser)
     Select a frequency to play and click on play button (arrow).
     Adjust volume by sliding the volume nob. Make all frequencies the same volume.
     Select a second frequency to play and click on play button (arrow).
     Count the number beats heard in 5.0 seconds.
     Divide by 5 to obtain the number of beats per second.  OR if you are really good just count the number of beats in one second.
     Compare the beats per second to the difference between the two frequencies making up the tone.

Frequency = 440  

Frequency = 441 

Frequency = 442 

Frequency = 443 

Frequency = 444 

Frequency = 445 

Frequency = 450 

Frequency = 480