Further, we can vary resonance frequencies by moving our tongue, lips, jaw, and so on. (scientificamerican.com)
Different organs of the human body produce different resonance frequencies. (phys.org)
«Our results suggest that a cell pattern with a smaller stretching transformation coefficients ratio (i.e. width to length ratio of the unit cell) leads to higher resonance frequency absorption and produces a wider tunable bandwidth as well.» (sciencedaily.com)