Developed a series of experiments on the interference of sound waves. Frequency signal generator circuit using IC Times Mercury 555 and LM386 IC to create a signal amplifier and audio will be entered by Vitro's Kun. There was a second wave train separately. After each wave train moves to unite the interference or cleared up. (Noise or sound), a condenser microphone to receive audio signals such. The audio signal is sent to the computer's sound card. Using the LabVIEW programmers get up and display of signal. When tested for the speed of sound in air is found at a frequency of 2,000 Hz, a frequency that can be tested for the speed of sound accurately as possible, with a 344 ± 2 m / s, and the test for the speed of sound in air. 1,500-5,000 Hz frequency range that is 342 ± 9.1496 m / s.