How Does A Subwoofer Work?

Subwoofers are the backbone of every sound system. Without one, the sound feels empty and incomplete.

Many audiophiles add subwoofers to their computer speakers and home theaters. Moreover, those who want some hard bass on their way to work will install a subwoofer in their car.

However, subwoofers weren’t always something most could afford.

For a long time, subwoofers were only used in the music industry, and only high-profile music enthusiasts could afford them. They became affordable in the last couple of decades, and since then, their popularity has skyrocketed.

Today, it’s almost impossible to imagine a good home sound system without a subwoofer. Some even buy them because they’ve heard it will improve the listening experience without knowing how they actually work.

So, if you think you need a subwoofer but aren’t sure how one works, stay tuned.

In this article, you’ll find out how a subwoofer exactly works, its components, and the different types of subwoofers.

Subwoofer Inside

Before diving into how a subwoofer works, we first need to define it.

A subwoofer is a special type of speaker that can reproduce low frequencies, specifically 20-200Hz. Simply put, with a sub, the sound won’t be distorted, and you’ll feel the bass.

How It Works

Sub Anatomy

Subwoofers consist of various parts that work together to achieve low frequencies and create a clear and deep sound.

Let’s get into the nitty-gritty and see how each subwoofer part affects its sound output.

Subwoofer Basket

Subwoofer Basket

The basket is the outer casing of a subwoofer. It's the sub's skeleton that holds all its other parts in place.

The casting is designed with vents on the sides to allow air circulation. Moreover, a subs casing is hollow and, together with the moving parts, participates in producing low frequencies.

Surround

Subwoofer Surround

The surround is one of the essential parts of a sub. It’s a flexible circular piece made from rubber or foam. 

The main purpose of a surround is to connect the cone/diaphragm to the basket and to keep it centered.

Because the surround needs to withstand the movement of the cone/diaphragm, it has to be made from a sturdy material that can keep up with the heavy excursions.

Cone/Diaphragm

Subwoofer Cone

The cone also referred to as the diaphragm, is the most vital part of a subwoofer. It creates sound by vibrating the air.

Because the diaphragm has such an important role, it must be carefully designed. Even slight design flaws can have an impact on the sound.

That’s why the cone is made from rigid and lightweight materials like organic fiber, metal, and plastic that can withstand vibrations. 

Dust Cap

Subwoofer Cap

As its name suggests, a dust cap is a small piece of plastic, metal, or alloy that protects the cone against dust.

The dust cap is located in the center of the diaphragm, and it either bulges inwards into the cone or protrudes slightly from its center.

Spider

Subwoofer Spider

Located just beneath the diaphragm assembly, the spider serves to monitor the up and downward movements of the cone. It’s attached to the voice coil and keeps it centered within the magnetic gap.

The spider is made from special fabric treated with resin that stiffens it. The name spider comes from its corrugated design.

This component also prevents dust from entering the magnetic gap and voice coil.

Tinsel Leads

Subwoofer Tinsel

Tinsel leads are wires that connect the voice coil to the speaker lead ports.

Because tinsel leads need to withstand extreme vibrations created by the coil, they’re usually very flexible and sturdy.

Voice Coil

Subwoofer Voice Coil

The voice coil consists of a thin copper wire that encircles the former, a cylinder. 

This component is sometimes referred to as the heart of the sub. It receives the audio signals from the amplifier as an electric current. 

The electric current flows through the voice coil, creating a magnetic field that pulls and pushes it against the magnetic gap.

Magnet

Subwoofer Magnet

The magnet's purpose is to direct the magnetic flux to the voice coil when a current is supplied. Often, it isn’t a stand-alone piece but is covered with a top and backplate.

Types Of Subwoofer

Subwoofer Types

Subwoofers come in two flavors - active and powered. Passive subwoofers draw their power from an external amp. They’re usually pretty good, but require a powerful amp to work.

Powered subwoofers come with a built-in amplifier. Moreover, they also feature in-line crossover that can do a decent work of adjusting the frequency range of the whole speaker setup.

Types Of Subwoofer Enclosures

It’s not all about the quality of the cone and the coils. Enclosures play a big role in how a subwoofer sounds. Let’s discuss the three types of enclosures you’ll find:

Sealed Enclosure

As its name suggests, a sealed enclosure is a box with no openings. Because it isolates the subwoofer’s back from the front, it produces a clean, tight, well-defined bass.

Ported Enclosure

A ported enclosure features a hole that allows for the air to get into the speaker. Because there’s more free airflow, subwoofers with ported enclosures can get pretty loud without breaking.

Isobaric Enclosure

Isobaric enclosures are very unique. They work by enclosing two subwoofer drivers in a single, sealed box. This allows it to push incredible amounts of power from both drivers while producing a tight, crisp bass.


Conclusion

Understanding how a subwoofer works is crucial since it gives you a general idea of what to look for when making a purchase. This guide may be brief, but it will save you the time browsing music shops for a sub that’s just right for your needs.


Barry Allen

About the author:

Barry Allen

I grew up to be a self-proclaimed stuck-up audiophile, and I – partially – blame Pinnacle Speakers for it.


The whole point of me starting this website was to keep the tradition going. Although the means have changed, the mission remains the same: Bringing „sterling sound“ as they once put it into home theaters and sound systems worldwide! 


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