狼音（wolf tone，wolf，不协调音，粗励音）由乐器的自然共鸣（natural resonances）引起，它是乐器设计的必然结果。所有乐器都具有共鸣箱，共鸣箱内的空气有一个基本振动频率（fundamental resonant frequency），在这个频率之上，乐器反应明显，并能产生音量较大的声音。共鸣频率（resonant frequency）取决于乐器的体积：体积越大，共鸣频率越低。就弓弦乐器中的小提琴家族而言，当琴箱空气振动基本频率与乐器皮肤和背板的基本振动频率非常接近，演奏这某个音的时候，引发皮肤，背板和空气腔的共振（synergy），产生一个额外的的大音量声音，这个听起来令人不快的声音就是狼音。尤其在弦乐器上，这些共鸣效果可能导致谐波范围（harmonic spectra）内的泛音消失，原因是皮肤和背板的不协调振动（异相振动）。

A wolf tone, or simply a "wolf", is produced when a played note matches the natural resonating frequency of the body of a musical instrument, producing a sustaining sympathetic artificial overtone that amplifies and expands the frequencies of the original note, frequently accompanied by an oscillating beating (due to the uneven frequencies between the natural note and artificial overtone) which may be likened to the howling of the animal. A similar phenomenon is the beating produced by a wolf interval, which is usually the interval between E♭ and G♯ of the various non-circulating temperaments.