Can a singer's unamplified voice really shatter a wine glass

Settled in 2005 by demonstrated with an unamplified voice by vocal coach Jaime Vendera (Discovery Channel/MythBusters, 2005); mechanism confirmed by acoustic/FEA engineers.

The 1972 Ella Fitzgerald/Memorex 'is it live or is it Memorex' ad popularized the idea, and for decades it was treated as mostly a myth or an amplified-speaker trick. The physics -- a glass has a natural resonant frequency, and a sustained tone at that exact pitch and high enough sound pressure level (roughly 105 dB or more, held for a couple of seconds) can pump enough energy into the glass to exceed its fatigue limit -- was well understood well before, but it was hard to do unamplified because it requires precise pitch control and extreme, sustained vocal loudness. Vocal coach Jaime Vendera settled the practical question by repeatedly shattering wine glasses with his bare voice on camera in 2005, and engineers have since reproduced the mechanism in finite-element vibration simulations. The status is solved as physics (resonance plus material fatigue), though it remains a rare feat because of the vocal demands.

An ordinary human voice, tuned to exactly the right note, can pour enough energy into a wine glass's own preferred way of vibrating to tear it apart.

Explanations that circulated

• It's just a movie/advertising special effect and physically impossible for an unamplified human voice
• Any loud enough note will do it, regardless of pitch

References

• Fact or Fiction?: An Opera Singer's Piercing Voice Can Shatter Glass, Scientific American staff, Scientific American, 2007
• Digital Debunking: Can You Actually Shatter Glass with Your Voice?, Siemens Simcenter blog, Siemens Simcenter (blog, with finite-element resonance simulation), 2019