A tubular metal chime normally produces a fundamental tone blended with some additional frequencies in the form of overtones. These fork chimes have an additional batch of tones added to the mix, many of them prominent enough to be heard not just as overtones but as harmonically meaningful components. The additional frequencies are the tuning fork modes, arising from the bifurcated form of the chime’s lower end. Striking the chime in different locations brings out the tones in varying blends so that a single chime can produce diverse harmonic territories, overlapping but still differentiable. For some fork chimes, you can create a wah-wah effect by covering and uncovering the open end on the unforked side.