This project simulates sound wave interference. There is one speaker at each end. Each of these speakers is powered by an independent sinusoidal signal generator. The model shows the two waves crossing each other along with the sum of their amplitudes. The two free ends can also be anchored to show standing waves.
For detailed instructions on using the program, take a look at the info window from the Speakers-Twodriveforces model.
Click on one of the pictures to see a quicktime movie of the model: