The National Anthem in Difference Tones (2008)

This piece is fairly self-explanatory. Two very high sine tones are heard, the difference of whose frequencies are the melody of The Star-Spangled Banner. The tune itself is not actually present in the recording, but is perceived as a kind of aural illusion. Difference tones are believed to be a psychoacoustical phenomena rather than an acoustical one, meaning that they are the result of neural processes within our brains.

This recording should be played quite loud in order to hear the difference tones clearly.

duration: 2:20 | mp3