This video describe how to measure the frequency of sound using the built in microphone on a MacBook Pro and the software LabVIEW. This program could be used to tune a musical instrument. In this example I use a frequency generator hooked up to a speaker to produce noise at a specific frequency. In LabVIEW it is a very quick process to measure the frequency of a sound, this can be achieved without any additional hardware besides the microphone on your laptop. In principle, this should work on a PC or a Mac. The example is on a Mac. It also shows how to use the Tone Measurement VI in LabVIEW.