Have you ever wondered how when you speak or sing others can hear you? How can you hear audio sounds around you?
Any sound or noise that is within a range the human ear is capable of hearing is called audio.
If you have a normal hearing, you can hear sounds between 20Hz and 20,000Hz but by the time you hit middle-age (35-58), you can expect to hear up to around 14,000Hz. It’s no fun getting old…
That explains why last weekend when I went out with friends, one of my friends who was sitting across the table kept asking me to speak louder even so it wasn’t that noisy at the restaurant. I was getting rather uncomfortable speaking so loud, but he said that it was his hearing… Next time when that happens to you, don’t think there’s something wrong with your voice!
If you are like me and love animals, you probably already know that your cat or dog can hear sounds that you don’t. Cats evolved extended high-frequency hearing without the sacrifice of low-frequency hearing, and their range extends further than ours. They can hear sounds in the frequency range of 45 to 60,000 hertz. That’s 40,000Hz higher than you and I can hear!
So what is sound?
It’s a vibration that travels in a wave-like pattern, and they are called sound waves. Sound waves move by vibrating objects, and these objects vibrate other surrounding objects, carrying the sound along.
Did you know that if we were to remove all the particles from the space around us, there would be no sound? Because there’s nothing for sound particles (waves) to bounce off in a vacuum.
The pitch of the sound is determined by the speed of vibration called Frequency.
The frequency is measured in units called hertz (Hz) or cycles per second. Hertz is the derived unit of frequency after Heinrich Rudolf Hertz, German Scientist who was the first person to provide conclusive proof of the existence of electromagnetic waves.
Sound can move through air, water and solids, as long as there are particles to bounce of off. And here’s the most exciting part, it seems that sound doesn’t move randomly, it can create organised shapes and patterns when exciting different types of medium like liquid, gas and sand.
The shapes are influenced by the frequency spectrum of the vibration because each vibration mode is characterized by a specific frequency.
Is it possible to visualise audio frequencies?
Yes, it is and it’s called “Cymatics”, after Hans Jenny, Swiss physician and natural scientist who is the father of Cymatics.
As a child he was a gifted keyboard player, and after completing his doctorate, he taught science before setting up his medical practice. His naturalistic approach and view of the Cymatics and sound made him realise that sound is the creative principle.
He said: “It must be regarded as primordial. No single phenomena category can be claimed as the aboriginal principle. We cannot say, in the beginning, was numbers or in the beginning was symmetry, etc… they are not themselves the creative power. This power is inherent in tone, in sound”.
The video below is a masterpiece by Nigel Stanford, that illustrates 7 experiments:
Chladni Plate – the sand creating different patterns depending on the pitch of the sounds.
Hose Pipe – water appearing to freeze in a sine wave shape.
Speaker Dish – liquid moving and dancing, funny enough, in this case it is vodka, because it’s thicker.
Ferro Fluid – where magnetic fluid forms into a big spiky ball.
Plasma Ball – being able to turn the Plasma Ball on and off with each note of the keyboard.
Ruben’s Tube – a long pipe filed with propane. When tones match resonant frequency of the tube, it forms high and low pressure zones of gas and produces beautiful effects with varying heights of flames.
And the grand finale with the Tesla Coil – high voltage device that generates arcs of electricity in the air. Guys are wearing protective suits and the show is spectacular, using high pitched synthesisers. Enjoy!
You can find out more from behind the scenes of the video here