If you plan on using your voice alone to shatter your glass, you’ll only need a sturdy platform to place your glass upon. The platform should be relatively high so that you can stand while singing to get the best volume and tone. [3] X Research source Lay down a large drop cloth if you attempt this in a carpeted area. Small splinters of glass can become embedded in carpet and cause harm later. A drop cloth will keep shattered glass from getting in your carpet. When using an amp and microphone, the amp should be placed facing your glass and relatively close to it. A sturdy coffee table might be sufficient to hold both speaker and glass while limiting distorting vibrations, though the ground might also work well. Try to position your amp so it isn’t blasting sound in the direction of people who might be bothered by it, like your neighbors. Your glass should be directly in front of the amplifier’s speaker. Look through the material covering the front of your amplifier and find the exact location of the speaker cone. Position your glass right in front of the cone. [4] X Research source [5] X Research source
If you don’t happen to have protective eyewear handy, you could use a pair of cheap sunglasses or swimming goggles. Be sure that your eye protection covers your entire eye. Half-lens reading glasses will not be adequate. [6] X Research source
You can also cause your glass to hum its resonant frequency by moistening your finger and rubbing it along the rim of your glass. Circle the rim of the glass with your finger until it resonates audibly. Then try to hold that pitch in your head. You may find using an instrument or tool, like a piano or a pitch finder, can help you identify, hold, and narrow in on the resonant frequency while you’re trying to sing. Empty your glass completely, remove decorations from it, and place it on a sturdy, regular surface while you are checking its resonant frequency. Things that are inside, on top of, or connected to your glass could alter this tone. [7] X Research source
Check your pitch frequently as you attempt to shatter the glass with your voice. Simply flick the bulb of the glass gently with your fingernail, listen carefully to the resulting tone, and tweak your pitch to match it.
The 100 - 110 decibel range is similar to the noise produced by a nearby power mower, power saw, or motorcycle. To shatter glass, you’ll have to reach this volume or louder while singing the resonant pitch. [9] X Research source [10] X Research source
To check just how loud you are singing, you might want to download a sound measuring app from the app store on your phone or buy a sound level meter from an online retailer. If you notice that, even at your loudest, you’re nowhere close to the 100 - 110 decibel range, you might want to consider using a microphone. [11] X Research source
If you feel discomfort, pain, or notice a significant change in the quality of your voice, you may be straining your voice by singing too loudly or too long. To prevent permanent damage, you should stop immediately, drink some water. Hold off singing until your voice is back to normal. [12] X Research source Vowel sounds will be less obstructed, enabling you to achieve higher volumes. In particular, the “ee” vowel sound has the highest volume rating. The vowel “ay” is also rated very highly for volume. Sustain your note as long as possible while making slight adjustments. Even if you hit the resonant frequency dead-on, you’ll have to hold the pitch perfectly for a few seconds before the glass vibrates enough to shatter. More likely you’ll have to “slide” your voice slightly up and down and make slight adjustments to match the resonant pitch.
You might also want to try glasses of various shape and size. Be sure you check the resonant frequency of each glass with a flick of your nail; each glass will have its own slightly different resonant frequency.
You may want to avoid using a vacuum cleaner to suck up your glass fragments. Doing so can cause damage to your vacuum. Instead, sweep up as much as possible with a broom, and capture tiny slivers by pressing a piece of bread into the fragments. [13] X Research source
You’ll also need to plug a microphone into your amplifier. You should place your mic as far away from the amplifier as the cable will allow to prevent distortion and mic feedback. Use a microphone stand if you have one available. Singing hands free will allow you to focus more intensely on the task at hand. Remember to wear your ear protection. Also, to minimize your exposure to loud volumes, you should stand behind the amp, or behind it and off to the side. If your mic doesn’t work, check it for an on/off switch. If your mic is already switched on but still is not working, check the audio jack to make sure your it is fully connected to the speaker.
You may want to layer the wall your amp is pointed at with sound dampening material, like heavy blankets or cushions. This will prevent the loudness of your amp from aggravating others. Other sound dampening measures you might make use of include acoustic panels, soundproof curtains, and other techniques.
If your glass refuses to break, check your pitch with a pitch finder. The pitch you are singing might only be off a slight bit, but this can prevent your glass from breaking. Vowels are less obstructed and will help you to achieve louder volumes. In particular, the “ee” vowel sound has the highest volume rating. The vowel “ay” is also rated very highly for volume. Sustain your note as long as possible while making slight adjustments. Even if you hit the resonant frequency dead-on, you’ll have to hold the pitch perfectly for a few seconds before the glass vibrates enough to shatter. [17] X Research source Since you are using amplification, you shouldn’t need to shout into the microphone. Speaking loudly puts strain on your voice and can do permanent damage if you’re not careful. Sing into the microphone at a moderate volume and take a break whenever your voice feels tired. [18] X Research source
A common trick for picking up small shard and slivers of glass uses a slice of soft sandwich bread. Press your bread into the floor wherever you see glass. The glass should get caught into the bread, which you can throw away when the glass is clean or the piece of bread is full of glass. You may need to use several pieces of bread to clean the entire area.
