Eisco Labs Aluminum Tuning Fork; 128 hz

This aluminum tuning fork is tuned to 128 Hertz and measures 9.25 inches in length. A tuning fork's frequency is set by the mass and stiffness of its tines, so lower frequencies require longer tines. At 128Hz the tone is low enough that its wavelength in air runs roughly 2.7 meters at room temperature, which places the first resonance in a resonance column at a measurable distance. Aluminum is the standard material for a fork of this type. It is light enough to ring for a usable duration after a soft strike and holds its tuning through repeated handling. The fork should be struck against a rubber block rather than a bench or hard edge, since impact dents the tines and shifts the pitch.