The folds vibrate at a fundamental ... end, singers often modify the resonances of their tract to produce a characteristic "vocal ring" that considerably boosts the sound output in this frequency ...

In 1860, physicist Hermann von Helmholtz — famous for his law of the conservation of energy — devised an equation relating the wavelength of a pipe’s fundamental tone (the lowest frequency ...

The research is described in Physical Review Letters. Frequency combs are widely-used, high-precision tools for measuring and detecting different frequencies—a.k.a. colors—of light.