# How pure is the tone produced by a typical tuning fork in air?

When a musical instrument plays a note that note is usually just the highest amplitude contribution to the sound wave. That peak is known as the fundamental harmonic, and the Fourier transform of the sound wave also has peaks at higher frequency harmonics, known as overtones, and possibly at lower frequencies, called undertones. These peaks have finite width, and there's frequently some kind of overlap.

How pure is the tone produced by a typical tuning fork? Specifically, ignoring questions of the bandwidth of the peak, how much do overtones and undertones contribute to the sound of a tuning fork? The answer, of course, will be, "It depends on the tuning fork," but it is still interesting to ponder what is produced by typical tuning forks.

As you can see from the plot, the next highest peaks are about $46\operatorname{dB}$ down from the fundamental.