Combination tone
（重定向自Difference tone）
![Combination tones: Unison, just perfect fifth, and octave are played in top row while A440 is sustained in second row, producing third row sum tones and fourth row difference tones. Frequencies are marked in Hz. Midi example contains all four voices for illustration only. Play](/Images/godic/202501/09/Sum_and_difference_tones_A2203341.png")
A combination tone (also called resultant or subjective tone) is a psychoacoustic phenomenon of an additional tone or tones that are artificially perceived when two real tones are sounded at the same time. Their discovery is credited to the violinist Giuseppe Tartini (although he was not the first, see Sorge) and so are also called Tartini tones.