"It’s a Magnet, Not a Motor!" and Other Things You See on the Internet

We love our Facebook community. Really, we do. But sometimes, scrolling through the comments section on our gear posts makes us want to smash our heads against a wall of unrestrained subwoofers.

Whenever we post a picture of a massive speaker driver, like clockwork, the "experts" crawl out of the woodwork. You know who you are. You’re the guy whose profile picture is a blurry shot of a 1998 Honda Civic, and you confidently comment:

"That ain't a motor. That's a magnet. lol."

Look, we get it. When you hear the word "motor," your brain immediately jumps to a greasy V8 engine or maybe the thing that makes your weed whacker spin. Because your definition of a motor is limited to "things that make cars go vroom," you get confused when we use big-boy terminology for audio equipment.

Today, we’re going to take a painfully simple journey into 4th-grade physics to explain why the back of a speaker is absolutely a motor. We even had the infographic below made for actual toddlers, so hopefully, you can follow along.

What Is A Motor? (Try Not To Hurt Yourself Thinking Too Hard)

Let's start with definitions. You seem to think a motor only exists under a car hood.

In the world of actual science and engineering, a motor is broadly defined as an electromechanical machine that converts electrical energy into mechanical energy.

That’s it. It takes juice (electricity) and turns it into movement.

• Your ceiling fan? It has a motor.
• Your electric toothbrush? Motor.
• The vibration function in your phone when your mom calls? Tiny little motor.
• A speaker driver? A linear motor.

Just because it doesn't have pistons and require an oil change doesn't mean it isn't a motor. A speaker takes an electrical audio signal (electrical energy) and uses it to shove a cone back and forth (mechanical energy). By definition, that is a motor at work.

A History Lesson You Probably Skipped

This isn't new magic. The relationship between electricity and magnetism—the principle all electric motors rely on—was explored by heavy hitters like Michael Faraday back in the 1800s.

The modern "moving-coil" speaker as we know it was largely finalized around 1925 by Chester Rice and Edward Kellogg at General Electric. You can even look at their ground-breaking work in US Patent 1,707,570A. They didn't just glue a magnet to a paper plate and hope for the best; they engineered an electromechanical transducer. A motor.

The Anatomy of the Speaker Motor

Look at the pretty picture we provided above. See how happy the sun is? Try to be like the sun.

If you look at the bottom half of that image, you’ll see the components of a speaker driver. When you combine these parts, they form the motor structure.

1. The Permanent Magnet (The Boss): Yes, there is a magnet. Good job spotting the big heavy thing. But a magnet sitting by itself on a table does absolutely nothing. It’s just a paperweight. It provides a static magnetic field.
2. The Voice Coil (The Spinner/Shaker): This is a coil of copper or aluminum wire wrapped around a former. It sits tucked inside the gap of the permanent magnet. When your amplifier sends electricity (music) into this coil, it becomes an electromagnet.
3. The Motor Action: This is where the magic happens. The permanent magnet has a fixed field (North and South poles). The voice coil, when energized by music, creates its own magnetic field that rapidly flips back and forth depending on the frequency of the sound.

Because opposite magnetic poles attract and like poles repel, the energized voice coil starts fighting with the permanent magnet. Since the permanent magnet is too heavy to move, the voice coil gets shoved forward and backward violently.

Electrical Energy (Music signal into the coil) -> converted into -> Mechanical Energy (The coil physically moving).

THAT IS A MOTOR SON.

That moving coil is glued to the speaker cone. The cone moves air. The moving air hits your eardrums. You hear The Wheels on the Bus from your speakers? Science.

Don't Believe Us? Ask The Industry Giants.

We know you probably won't take our word for it because you read a forum post once in 2008 that said otherwise. Fine.

Maybe you’ll believe some of the biggest names in car audio, who have been engineering these massive drivers for decades. They all refer to this assembly as a motor.

• Check out JL Audio, arguably the kings of subwoofer engineering. Their tech papers and product descriptions constantly refer to their patented "motor systems." You can read about their intense engineering right on their technology page.
• Look at Rockford Fosgate. They’ve been melting faces since the 80s. They discuss motor topology and design constantly. Here is a basic breakdown on their site about how speakers work.

Class Dismissed

So, the next time you feel the urge to type "It’s just a magnet" on one of our posts, take a deep breath, look at the toddler infographic above, and remember that a magnet is just a rock that sticks to your fridge until you add electricity and engineering to it.

It’s a motor. Deal with it.