Sympathetic Resonance

It is possible to generate sympathetic resonance by activating a pitch which is shared by the harmonic series of a different string, which must be un-muted and allowed to freely vibrate when activated by the articulated pitch.
​The lower partials of the relevant harmonic series are generally more easily activated and will ring with greater clarity and sustain.

Note: although you don't notice it in the video, the same note on the lower string is vibrating for sympathy.

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