| Tuning Fork: When struck by the hammer tool, the tuning fork vibrates, producing sound waves at a distinct frequency that depends on the length of the fork's tines. You can place between one and ten tuning forks and move them freely around the simulation window. With the Select tool, you can resize the tuning fork's tines and change the tuning fork's frequency. Use the handles on the tines. You can opt to attach a resonance box to a tuning fork. If the length of the box is equal to the length of the tines or an integral divisor of the length (1/2 the length, 1/3 the length, 1/4, etc.), then the tuning fork produces sound waves at a resonant frequency of the box. The resonance amplifies the sound. If the box length is not a resonant length, the box could actually dampen the sound waves. In the tuning fork's Properties Box, you can change the frequency (and hence the tines' length) of the tuning fork. The default frequency is 470 Hz. You can also allow for simultaneous strike. All tuning forks with this option chosen will play when any one of them is struck with the hammer tool. The tuning fork is one of nine sound sources in Sound Lab.