In the 1990 movie The Hunt For Red October, a stealth submarine is located by what a computer thinks are seismic sounds, but when sped up, they are clearly mechanical. We won’t spoil it further on the off chance that you haven’t seen. We can’t help but wonder if [Prof. Jeff Moore] and his team at the University of Utah were inspired by the movie. Why so? Because they have taken the seismic vibrations of the beautiful arches in Utah, US and sped them up 25 times, placing them right in the range of human hearing on their Red Rock Tones website. Go have a quick listen. We’ll be right here.
The resulting sound bites are just beautiful, and some of them have an almost eerie underwater tone to them as if driven along by a clandestine propulsion system. But that might just be our imagination running away a bit. That’s likely the point of this scientific exercise, however- taking raw scientific data and making it accessible and somehow relevant to even non-geologists.
[Prof Moore] and his team aren’t just placing seismometers on natural rock arches for the fun of it, even though that does sound like some fun. Instead, they are studying the natural resonances of these rock formations- both the primary frequencies and the harmonics. By monitoring changes in their resonant frequencies over time, they gain an understanding of how the rock is changing- especially as it relates to the impact that humans have on these natural wonders.
What’s more, these audible representations of seismic waves are something that may be possible for the determined hacker. We’ve featured several DIY seismometers such as this hacked USB mouse designed to detect elephants on the move. Could it be sensitive enough for measuring seismic activity? Try it out, and let us know!
Special thanks to [Prof. Jeff Moore] for permission to use the images for this article.
Speaker cone materials can be a deep rabbit hole ranging from inexpensive paper to kevlar. We’ve all cut apart, or blown out, the cheapies to see their inner workings, but the exotic material list does not stop at audiophile-quality models. It can include mirrors, microwave ovens, and a European hacker’s forehead. Video also after the break. In addition to the speakers with expensive elements, there are sound-generating transducers with no cones. These are sometimes called surface speakers, and they vibrate something, anything, to make a sound. At their cores, they have many of the same parts, and making a surface speaker from a traditional speaker is not difficult.
The first step is to find a raw speaker, one with no crossover components, possibly from a garage sale or from a set your spouse insists are outdated, ugly, and better off as firewood. Power specifications should not change since we will be using the same solenoid, and that means your amplifier can follow the speakers back from the dead. The video provides step-by-step instructions, and the goal is to create a module with a moving shaft, but the range must be limited so it cannot be pushed back into the speaker or pulled away, both could destroy it. Once you have that, go around and make everything noisy. Don’t use this on pets or children, but spouses are fair game.
We would love to see a chip bender experiment with different speaker mediums to add an extra layer of complexity, but for the rest of us, bone conduction is already a real thing, and if you enjoy impractical speakers, you are not the only one with your head in the clouds.
In a move guaranteed to send audiophiles recoiling back into their sonically pristine caves, two doctoral students at ETH Zurich have come up with an interesting way to embed information into music. What sounds crazy about this is that they’re hiding data firmly in the audible spectrum from 9.8 kHz to 10 kHz. The question is, does it actually sound crazy? Not to our ears, playback remains surprisingly ok.
You can listen to a clip with and without the data on ETH’s site and see for yourself. As a brief example, here’s twelve seconds of the audio presenting two versions of the same clip. The first riff has no data, and the second riff has the encoded data.
You can probably convince yourself that there’s a difference, but it’s negligible. Even if we use a janky bandpass filter over the 8 kHz -10 kHz range to make the differences stand out, it’s not easy to differentiate what you’re hearing:
Lasers work by emitting light that is “coherent” in that it doesn’t spread out in a disorganized way like light from most sources does. This makes extremely focused beams possible that can do things like measure the distance from the Earth to the Moon. This behavior isn’t just limited to electromagnetic waves, though. [Gigs] via [CodeParade] was able to build a device that produces a tightly focused sound wave, essentially building an audio laser.
Curiously enough, the device does not emit sound in the frequency range of human hearing. It uses a set of ultrasound speakers which emit a “carrier wave” in the ultrasound frequency. However, with a relatively simple circuit a second signal in the audible frequency range is modulated on top of it, much the same way that an AM radio broadcast has a carrier wave with an amplitude modulated signal on top of it. With this device, though, the air itself acts in a nonlinear way and demodulates the signal, producing the modulated signal as audible sounds.
There are some interesting effects of using this device. First, it is extremely directional, so in order to hear sound from the device you would need to be standing directly in front of it. However, once the ultrasound beam hits a solid object, the wave is instantly demodulated and reflected from the object, making it sound like that object is making the sounds and not the device. It’s obvious that this effect is hard to experience via video, but it’s interesting enough that we’d like to have one of our own to try out. It’s not the only time that sound waves and electromagnetic waves have paired up in interesting ways, either.