When two waves with different frequencies combine, they can produce a phenomenon known as "beats" or "combination tones." However, it's important to note that these beats do not result in the formation of a new frequency.
In the case of beats, the two waves have slightly different frequencies, resulting in periodic variations of constructive and destructive interference. The interference pattern created by the superposition of these waves produces a beat frequency equal to the difference between the frequencies of the two original waves.
For example, let's consider two pure tones: A wave with a frequency of 400 Hz and another wave with a frequency of 410 Hz. When these waves combine, they create beats with a frequency of 10 Hz (410 Hz - 400 Hz = 10 Hz). The beat frequency is perceived as a variation in the loudness or intensity of the sound rather than as a new distinct frequency.
The reason we don't perceive a new frequency is that beats arise due to temporal variations in the interference between the two waves. The individual frequencies of the original waves remain distinct and can be perceived separately. The beat frequency represents the rate at which the amplitudes of the waves alternately reinforce and cancel each other, resulting in the perceived beat phenomenon.
In summary, the phenomenon of beats occurs when two waves with slightly different frequencies interact, leading to variations in constructive and destructive interference. These variations result in a beat frequency that represents the difference between the frequencies of the original waves. However, no new frequency is generated in this process.