Text: "The LAW is strictly true only when the amplitudes are exceedingly small. When the disturbance of the air by a sounding body is so violent that the law no longer holds good, secondary waves are formed, which correspond to the harmonic tones of the sounding body." "When two tones are rendered so intense as to exceed the limits of the law of superposition, their secondary waves combine to produce RESULTANT TONES. "Resultant tones are of two kinds; the one class corresponding to rates of vibration equal to the difference of the rates of the two primaries; the other class corresponding to the rates of vibration equal to the sum of the two primaries. The former are called DIFFERENCE TONES; the latter SUMMATION TONES. See Russell's 4++

See Also: ROOT, KEYNOTE, LAW OF TRIANGLE, LAW OF PROPORTION, LAW OF ASSIMILATION, HARMONIC & INHARMONIC, POWER OF HARMONICS

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