Can you break a glass just by singing for it?
Breaking glass with voice.
The human voice is a strange and unique instrument. No other species has the capability to vary the sound as much as a human being. That’s, of course, because we communicate with words. And to pronounce words we need a lot of variations to the sound of the voice… The vowels. There are five vowels in English, but 20 vowel sounds. In other languages there can be many more, And then there are all the consonants. The jaw moves up and down, and the tongue in all directions.
Maybe that’s one of the reasons, human beings like to sing. We are actually very good at it, at least some of us are.
The thing about the voice is that it can’t produce very strong sounds. The Opera-singer doesn’t really sing in a loud voice. It’s more of a very focused voice, one that has a metallic ring to it. That ring passes through the sound of the orchestra. Then the audience’s brains put an imaginative voice to the high-pitch ringing sound that they hear. And suddenly the small vocal cords of 1,5 centimeters sound all the way to the back of the concert hall. It’s magic.
The frequency
Every sound has a frequency. That’s what the black and white keys on the piano are for. When there’s a sound, all the information of that sound travels through the air as sound waves. When a sound wave hits the eardrum, the latter vibrates with the soundwave. All the information about the sound is then transmitted to the brain. And we can tell if the voice was good, bad, soft, powerful, and we understand the frequency. We know if it’s in tune.
And every object has its own frequency. If you knock on it, it will put out some sort of sound, a tune. The frequency depends on the material and the shape. That’s why a Stradivarius Violin costs several million dollars and a new handmade Chinese Violin can cost a few hundred, although they’re both handmade out of wood. The Violin’s own frequency, the resonance is different.
The breaking theory
If you want to start breaking glass with your voice, here’s how you do it. When an elastic body vibrates, it vibrates at the body’s natural frequency. These vibrations are called Natural Vibrations. Forced Vibrations are vibrations coming from an external source, a voice or a loudspeaker for example. If the Forced Vibration is the same as the Natural Frequency, the vibrations’ amplitude increases manifold. If the increase of the vibration from the external force is more than the decrease from the resistance in the material, the vibration builds up.
To start breaking glass with your voice, you need to find the glass’ natural frequency. Then you have to put more sound energy into the glass than the glass is able to dampen. In that case, the vibrations will build-up, and if you continue, eventually it will break.
Break glass by singing – This is what you need
- You need a glass. Choose one with a big cup and thin walls. It should have a good ring, natural frequency, to it. Knock on it or move your wet finger on the rim, to hear the sound. The vibration mustn’t die out fast but continue for a while.
- Then you need to prepare the surroundings, protect your mouth, eyes, and body, and get children and dogs out of the way. You’re breaking glass here… (Actually, you should keep your mouth as close as possible, and doing so is risky. You shouldn’t do it alone. And use some sort of protection for your eyes.)
- Put it on a table at the height of your mouth. Or hold it in your hand. The glass has to be empty.
- Find the frequency and sing that note. When you sing the right note and stop suddenly, the glass should continue for a few seconds. If it doesn’t, it’s not the right frequency. You could try different vowels.
- When you got the frequency right, you just have to produce a loud sound. You would need a very strong voice to break the glass by singing… At least 100 -105 dB. And you need to keep the exact frequency for a long time, to make it build up.
- If the glass has some small defect, a very small undetectable crack, it’s much easier. A perfect glass is close to impossible to break. Try another one if you don’t succeed.
Now, to who actually can do it
It is said that the famous tenor Enrico Caruso was able to break a glass with his voice. His wife claimed he never did it though.
Many other Opera singers have had that epithet too, like the Swedish soprano Birgit Nilsson, the famous Maria Callas, and others. Even Ella Fitzgerald remembered in an interview how she in 1972 at an audition for Memorex, cracked a glass by singing How high the moon by Morgan Lewis.
And in the end, if you just want to get the glass broken, it’s not difficult at all. I do it all the time…
Conclucion
Yes, you can brake a glass just by singing. But it’s not only the strength of the voice that does it. It depends on the glass, and on the pitch.
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