When playing a musical instrument by ourselves or in a band, one of the most important things to keep in mind is that the instrument is properly tuned. Any failure in doing so will result in a poor sound quality, regardless of our technical abilities. This little program allows us to tune almost any musical instrument simply by using our computer's microphone. By default, its interface is set up to display the guitar's standard tuning (E, A, D, G, B and E); thus, if guitar is your instrument, you can simply place your microphone near your guitar's soundhole, click on the button corresponding to the string you want to tune (say, the fifth or A string) pluck the corresponding string, and watch the program's interface. It will show the required frequency (in Hz), as well as the difference between this and the frequency emitted by your string; it also will show graphically this difference and a red arrow will indicate if you need to tighten or loosen the string.
If you want to tune an instrument other than a guitar, or if you want to try any of the multiple alternative guitar tunings used in music, then you can choose the Chromatic tuning feature. It allows you to find any reference tone and semitone to tune almost any instrument. It is hard to believe that such a useful, attractive and easy-to-use program can be also completely free, but it is. Don't miss it.