Gorilla University: How do Vibration Speakers Work?

How do Vibration Speakers Work?

With almost all smartphones and tablets there are one major complaint that almost everyone can agree on. There is one flaw that most smartphones and tablets have...the speakers on their phone or tablet just aren’t loud enough.

Sure, there are portable speakers that you can buy, but a lot of times the sound quality on those types of speakers can be tinny, weak, and just lacks that powerful bass that a traditional sound system can give you.  Another solution to this problem is to just put on a pair of headphones, the sound quality is way better than a portable speaker, but you really can't share your music with anyone else.

There is a third solution to this problem that not many people have heard of. They are called vibration speakers, sometimes referred to as vibration transducers.

Obsidian Speaker

This type of speaker turns any surface into a speaker, duplicating the sound waves over and over through the surface giving you a fuller richer audio experience. Mount it on a window, a table, or a counter top and you'll experience some pretty spectacular sound quality. The sound that is possible out of this type of speaker will genuinely surprise you.

These speakers are no bigger than any other portable wireless speaker. So, if the speaker isn't bigger how can a tiny little speaker create so much beautiful noise?

How do we hear sound?

To understand how a vibration speaker works we have to start with the basics of how sound itself works.

Sound at its core is basically “movement” it is molecules in the air moving around the room bumping into one another. They react to the impulses of the sound being generated. The speed of this movement of molecules is what makes us perceive a sound the way that we do.

Sound waves travel through the air every day of our lives. But air is not the only medium that sound waves can travel through. Sound can travel through water, actually much quicker than it can through air and through gasses. The molecules aren’t as active and allow the sound to travel and react much quicker.

How does sound travel in our ear?

So how do our ears actually pick up this molecule movement, and turn it into sound? It’s all thanks to our eardrums. An eardrum is a thin piece of skin on the inner part of your ear, that when the colliding molecules hit it, it vibrates. Then tiny connecting bones that are connected to the eardrum transfer these vibrations through something called a cochlea.

This is another structure in your inner ear that contains fluid. The vibrations press against the liquid and another organ called the Corti translates the vibrations into electrical impulses that travel along your auditory nerve to your brain, and our incredible brain converts these signals into what we know as sound. There’s a lot of complex processes going on in our bodies that we take for granted.

How does our brain hear sound?

So enough biology talk, let’s talk about speakers.
A Speaker is made up of a few parts. The parts on the outside of the speaker are the suspension, the diaphragm and the dust cap. The suspension is the frame for the diaphragm. The diaphragm is basically just a simple cone and the dust cap sits right in the center. The dust cap is protecting the inner part of the speaker called the voice coil.

How do vibration speakers work?

The voice coil is a movable piece within the speaker. It's also an electromagnet. Passing current through the coil creates a magnetic field. Reversing the current, switches the polarity of that magnetic field. At the base of the speaker is a permanent magnet. When the polarity of the magnetic field of the coil matches that of the permanent magnet, the two like fields repel one another and the coil moves outward, pushing the diaphragm. When the magnetic forces are opposite one another, they attract each other. This pulls the coil inward, pulling on the diaphragm.

A vibration speaker is similar, except that there's no diaphragm. Instead, the voice coil attaches to a movable plate. Setting a vibration speaker down on a solid surface positions the plate so that it will vibrate against that surface.

Obsidian Surface Vibration Wireless Speaker

As current alternates in the coil, it moves up and down, pushing against the movable plate. The plate pushes against the surface, transferring the energy to the surface and turning it into a speaker. Because vibration speakers convert electrical energy into mechanical energy, they are also known as transducers. A transducer is a device that can convert one form of energy into another.

Play a vibration speaker through a table, a window, a counter top or any other surface

The solid surface will vibrate with the speaker, displacing air molecules around it. Just as with any other sound, your ear detects the movements of the colliding air molecules. Some materials reverberate better than others -- not all solids are created equal. In general, glass and wood tend to work best with vibration speakers.

You can even mount vibration speakers on the inside of a wall, leaving the speakers invisible to those in the room. Because the speakers transfer vibrations to the surfaces you mount them on, the wall itself will send out sound.

Manufacturers have found clever ways to incorporate vibration speakers into various products. One company creates vibration speakers that you can mount on a ski helmet, letting you listen to music as you hit the slopes. Others design speakers that you can mount on the underside of desks or tables, giving you a full surface to work with without the clutter of visible speakers. And then there are bone-conduction speakers, which transfer vibrations directly to your skull so that you both hear and feel the music at the same time!


Leave a comment

All comments are moderated before being published