Editing Combination tone (section)

{{Short description|Perceived tones when real tones are sounded}}
[[Image:Sum and difference tones A220.png|300px|thumb|Combination tones: Unison, just perfect fifth, and octave are played in top row while A220 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. {{audio|Sum and difference tones A220.mid|Play}}]]
[[File:Yankee Doodle combination tones.png|300px|thumb|Difference tones (bottom) between "[[Yankee Doodle]]" in F (top) and a [[drone (music)|drone]] on C (middle)<ref>[[Arthur Benade|Benade, Arthur H.]] (2014). ''Horns, Strings, and Harmony'', p.83. Courier, Dover Books on Music. {{ISBN|9780486173597}}.</ref> {{audio|Yankee Doodle combination tones TOP.mid|Play top}}, {{audio|Yankee Doodle combination tones BOTTOM.mid|drone}}, {{audio|Yankee Doodle combination tones BOTH.mid|both}}, {{audio|Yankee Doodle combination tones DIFFERENCE.mid|difference tones}}, or {{audio|Yankee Doodle combination tones ALL.mid|all three}}]]
{{multiple image
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 | header = Sum and difference of frequencies (left) and sum and difference of two pairs of sine waves (right) with frequencies of 1 and 2 (top) and 1 and 3 (bottom)
 | image1 = Sum and difference of frequencies of sine waves 2 and 3.png
 | caption1 = sum and difference of the frequencies
 | image2 = Sum and difference of sine waves 2 and 3.png
 | caption2 = sum and difference of the sine waves
}}

A '''combination tone''' (also called '''resultant tone''' or '''subjective tone''')<ref name="Brit">"[http://www.britannica.com/science/combination-tone Combination Tone]", ''Britannica.com''. Accessed September 2015.</ref> 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]],<ref name="treccani enciclopedia">{{cite web|title=Tartini, Giuseppe|url=https://www.treccani.it/enciclopedia/giuseppe-tartini/|publisher=[[Enciclopedia Italiana]]|access-date=1 April 2021}}</ref> so they are also called '''Tartini tones'''.

There are two types of combination tones: '''sum tones''' whose [[frequency|frequencies]] are found by adding the frequencies of the real tones, and '''difference tones''' whose frequencies are the difference between the frequencies of the real tones. "Combination tones are heard when two pure tones (i.e., tones produced by simple harmonic sound waves having no overtones), differing in frequency by about 50 cycles per second [[Hertz|[Hertz]]] or more, sound together at sufficient intensity."<ref name="Brit"/>

Combination tones can also be produced electronically by combining two signals in a circuit that has nonlinear distortion, such as an amplifier subject to [[Clipping (signal processing)|clipping]] or a [[ring modulator]].