There are those stories of singers shattering wine glasses with their voices and the such. Can our handheld devices do the same thing?
Would it be possible to build a smartphone app that can break windows, etc. by playing a tone, gradually increasing its frequency, and monitoring the feedback with the microphone until a resonance frequency is detected?
I’m not an expert on the subject, but wouldn’t you have to have speakers that can actually do that kind of resonating? I can’t compare voice chords to a 1 cm. speaker in my mind…
to break glass you would need to transfer enough of the right type of energy into the glass. just having the right frequency doesn’t mean that it will be enough energy.
Yeah. The phone can generate the digital signals to control a high powered DAC/audio amplifier/speaker system to actually break things. It could possibly analyze signals from a microphone in order to empirically determine resonant frequencies. For example, if you have a wine glass in an anechoic chamber, couldn’t you send out pulses of sound at over a frequency range, then listen for the frequency response from the glass? If this worked, you could listen for a signal to tell you when you are approaching a resonant frequency for the glass.
The app is just a computer program running on a very convenient computer packaged into a compact form factor and running on an OS that has some advantages over legacy desktop OSes. You could do the same thing by writing your code to run on a Linux desktop PC, which is the “conventional” way to solve this problem.
The “break anything” part of the question needs attention. Wine glasses are chosen in these demonstrations not because of any symbolism but because they are good resonators. Most things aren’t. You can tell the difference by flicking a wine glass and hearing it ring out for a while versus flicking a glass tumbler and hearing only a very short note. A run-of-the-mill window pane, drinking glass, or ceramic lamp will have many identifiable resonant frequencies, but those oscillation modes will be too damped to lead readily to large amplitudes even when driven at the correct frequency.
In other words, the amplitude of the oscillatory motion does not continue to increase just because the driving frequency is correct. The amplitude maxes out at a value related to the strength of the driving force and the level of damping intrinsic to the system. And most systems have lots of damping. Non-linearities also lead to a suppression of the peak amplitude, so just cranking the volume may not work either (until you start approaching what you would no longer call a resonant phenomenon).
It’s actually a subtle affair trying to break a wine glass. Breaking “anything”? Nah, not in any generalized way.