Whether it's a punk gig at Johnny V’s or a sold-out show at the City National Civic, all San Jose concerts rely on the same crucial piece of equipment: a booming loudspeaker. In fact, most events in San Jose do. But how do these workhorse speakers work? Read on to learn all about how your ears take in sound, and how loudspeakers help it get there.

What does a loudspeaker do?

Whether they’re as tiny as earbuds or as huge as the loudspeakers once found at the Roman Coliseum, speakers work according to the same basic principles. All sound travels through the air in the same way that waves travel through the ocean, so speakers need to convert the electrical signals they receive into motion and thus sound.

How does it amplify sound?

The mechanisms responsible for this translation are called drivers, which have three parts: a permanent magnet, an electromagnetic coil, and a cone. When the coil receives an electric current, it reverses polarity and is pulled toward the permanent magnet or pushed away from it. The cone moves accordingly, compressing the air inside the box and pumping amplified sound waves into the surrounding air. The frequency of the vibrations controls the pitch of the sound, and the amplitude controls the volume of the sound.

How does a loudspeaker reproduce all the complex sounds of music?

Top-quality speakers typically have multiple drivers dedicated to high, middle, and low frequencies in order to reproduce the full spectrum of audible sound, whether it’s a resonant speaking voice or an orchestra playing an overture. Woofers are the largest in order to move the volume of air necessary to make lower frequencies. Tweeters are the smallest, responsible for higher frequencies since they can vibrate fastest, and midrange drivers handle the frequencies in between.