The Sound of Music: How Speakers Produce Our Favorite Tunes

 

Music is all around us and can instantly put us in a good mood, but how exactly do speakers produce sound? The process of converting electronic signals into audible frequencies involves complex calculations and deep physics, but it’s not as complicated as you might think. Here’s a look at the science behind music and speakers so you can appreciate this art even more.

Bass

A speaker's job is to move air molecules in a series of waves. This creates the sound that you hear. A woofer is a subwoofer for bass sounds, like the kick drum or deep synth tones. The cones that produce these low-frequency sounds are typically made from paper or foam and can travel as far as 20 feet before they need to be replaced. On the other end of the spectrum, tweeters are designed for higher frequency sounds. They use small diaphragms made out of metal foil that vibrate with each wave to create a wide range of highs, like chimes, strings and synthesizers.

Treble

In order to understand the process by which sound is converted into an audible format, it's important to know a little about the physics behind the conversion. When sound vibrates air molecules, these molecules bump into each other and transfer their energy to adjacent molecules. This movement causes a compression and rarefaction in the volume of air particles; this fluctuation in pressure is what we call sound waves. These waves consist of high frequency acoustic vibrations that move quickly through space and are characterized by a high pitch, or treble tone. Low frequency acoustic vibrations travel more slowly through space and are characterized by a lower pitch, or bass tone.

Mid-range

A speaker consists of an electromagnet which is attached to a cone. The electromagnet produces an electric current, which makes the cone vibrate and produce sound waves. These waves then travel through the air, producing sounds in our ears. When these waves reach your eardrum, they create vibrations that cause hair cells on the inside surface of your ear canal to move back and forth. Your brain interprets these vibrations as sound. Tweeting, howling, and ringing are all produced by various frequencies or tones. 

Frequencies are measured in hertz (Hz) or cycles per second (cps). For example, you may hear someone say I can't hear anything! That's because their frequency range has been greatly reduced due to hearing loss. 

In-ear monitors enable musicians to play their instruments without the loud sounds bothering everyone else around them while also giving them great control over their own sound levels.

Woofers, tweeters, and cones

A speaker has three main parts; woofers, tweeters, and cones. The job of the woofer is to produce low frequencies and the job of the tweeter is to produce high frequencies. A cone is just a round piece of paper or plastic that vibrates in response to sound waves from the woofer or tweeter. When the cone moves in one direction, air particles are pushed out of the way. When it moves back to its original position, this creates a vacuum-like effect where new air particles rush in to take its place. In this process, we hear an audible frequency. Woofers move large amounts of air particles so they can be heard more easily while tweeters create higher frequencies that need less power to be heard by our ears.