Subwoofer parts explained (Anatomy of subwoofer speaker)

A subwoofer is a special speaker that makes super deep and thumping sounds called bass.

It helps us feel the rumble in music, movies, and games, like when you hear a big explosion or a powerful beat.

It’s like having a cool magic box for incredible low-pitched sounds!

A subwoofer typically consists of a bottom plate, a pole piece, and its ring, magnets and plates, a basket, a spider, a voice coil, terminals, a cone and surround, a basket gasket (rubber ring), a dust cap, and a cabinet.

It also includes cabling or wiring for the electrical supplies; the image below displays the anatomy of a subwoofer for better understanding.

Anatomy of a subwoofer

Key Takeaways

  • Subwoofer parts include the top plate, bottom plate, pole piece, magnet, woofer basket, spider, voice coil, terminals, tinsel leads, cone, surround, dust cap, and subwoofer enclosure.
  • Active and passive subwoofers are the two main types – Active subs have a built-in amplifier, while passive subs require an external amplifier to produce deep bass and rumbling effects.
  • Except for amplifiers and special features such as Bluetooth connectivity, the components primarily responsible for producing low-frequency sounds in almost all subwoofers are the same (in most cases).

Subwoofers parts (Components of a subwoofer speaker)

Let us start with the base part of a subwoofer and understand how it works and coordinates with the connected components.

Top Plate and Bottom Plate

The magnet of the subwoofer is secured between the top and bottom plates.

The top plate is fixed above the magnet and underneath the basket and is usually made of low-carbon steel.

On the other hand, the bottom plate is the base part of a subwoofer (also referred to as a backplate or end plate).

The bottom plate is typically fixed below the magnet, which pulls or redirects the excess heat flow through a hole (the pole piece), further helping the voice coil to cool down.

The magnetic force created by the magnet between the plates is directed to the voice coil through the hole in the pole piece.

The Pole piece

The Pole Piece is another important component in a subwoofer, as it helps to direct the magnetic field created by a magnet. It achieves the task of directing the magnetic force because of its high magnetic permeability.

In simple words, a pole piece is a combination of a plate and a pole.

The pole piece also helps in cooling the voice coil by moving the air back and forth through its hole; in other words, it allows proper ventilation to the voice coil.

Magnet

The magnets are the most important components of a subwoofer or any audio system.

The magnets create a magnetic field that is opposite to the electrical field supplied by the amplifier or receiver.

The reaction of the two opposite forces creates vibration, and the vibration is the actual sound we hear in the audio system.

That being said, there are different types of magnets used in Subwoofers or audio systems, depending on the requirements. Actually, it depends on the size and type of sound system.

The most common types of magnets used in subwoofers are Ferrite, Neodymium, and Alnico.

Also Read: Pairing Soundbar and subwoofer: Add a Subwoofer for bass

Woofer Basket

A basket, also known as a frame or the chassis of a subwoofer is connected to both the magnet and the cone assemblies.

In simple words, a basket holds the active parts of a loudspeaker or a subwoofer and is usually made of plastic, aluminum, mid-steel, and sometimes iron coated.

Baskets made of cast aluminum are generally used on more expensive speakers compared to those made from stamped or mid-steel.

Spider

A spider, in simple words, is a flexible component that works as the suspension system of a speaker or subwoofer. It is a corrugated woven component usually made of cotton, a poly-cotton blend, or conex.

It is typically placed below the cone, and it helps to maintain the linear movement of the voice coil in a back-and-forth motion, further creating sound waves that we are actually able to hear.

Basically, two types of spiders are used in subwoofers: a cup spider and a flat spider.

Cup spiders are usually found in inexpensive speakers or subwoofers, whereas flat spiders are mostly used inexpensive or high-excursion woofers.

The reason that flat spiders are more popular is that they offer more linear movement to the voice coils.

Voice Coils

A voice coil consists of two parts, i.e., a bobbin and coils.

The bobbin’s job is to hold the voice coil, whereas the coils create the alternating field inside the motor structure.

It is basically a tightly wound wire and is said to be the most crucial component of a subwoofer.

In simple words, a voice coil is a tightly wound spool of wire made of copper, aluminum, or copper-clad aluminum (CCA) that is wrapped around a bobbin.

The role of the wire gauge is quite crucial because it determines the power handling capacity of a subwoofer; hence, it is made of durable materials.

Furthermore, glue is used to secure the coil (winding wire) from falling off the former or the bobbin.

The voice coil is typically placed at the center of the motor, which is also a magnetic gap and connects to the cone and the spider of the subwoofer.

Also Read: Woofer VS Subwoofer: Difference between woofer and subwoofer explained

The Terminals

The terminals are simply referred to as the positive and negative points, or wire connections, of a subwoofer.

The most common terminals used in subwoofers are spring and ring terminals.

That being said, many other types of terminals are also available for different subwoofer categories.

Also Read: 2 ohm vs 4 ohm subwoofers: Ohm difference explained

Tinsel Leads

The tinsel leads are a type of electrical wire that is connected to the voice coils and can carry less power and bend more.

A tinsel wire is made by wrapping several tiny strips of metal foil around a flexible nylon or textile core.

Such wires or leads are typically used in cords of handsets, headphones, speakers, subwoofers, etc.

Cone

A Cone is another moving part of a subwoofer, along with the voice coil.

It creates pressure in the air by pushing and pulling the surrounding air during motion, which then outputs sound.

These components are usually made of lightweight materials such as propylene.

Propylene is said to be better than paper cones because it is lightweight and more durable.

Additionally, propylene is an inexpensive material and also prevents damage caused by moisture.

What’s more? Propylene has a slighter impact on sound quality.

Also Read: Subwoofer Low Pass Filter (LPF ) Explained

Surround

The cone of a subwoofer is attached to the frame by a surround, which is a key component of the subwoofer’s suspension system.

It protects the cone during motion and ensures that it is in place, moreover, it prevents the cone from deviating from its linear path during an excursion.

The subwoofer’s cone surround is typically made of treated foam and rubber that helps enhance its strength and flexibility. However, in some cases, urethane, Santoprene, and Butyl are also used in their making.

Even though rubber surrounds are a little stiffer than foam surrounds, they last longer. Foam surrounds, on the other hand, are great for high excursion and sound quality.

Dust Cap

The dust cap is made using a similar material to that of a cone and is mounted over the large central hole of the subwoofer.

It helps strengthen the cone’s structure and also contributes to the structural integrity of the voice coil.

It is usually curved like a dome and is one of the protective components that keeps the internal parts covered and safe.

Also Read: How to wire subwoofers? (Includes Subwoofer wiring diagram)

Subwoofer Enclosure

A subwoofer enclosure is a specially designed box that houses the subwoofer speaker.

It ultimately results in enhanced bass performance by preventing sound waves from canceling each other out, allowing the subwoofer to produce cleaner and more powerful low-frequency sounds.

That being said, the enclosure shape may vary depending on the brand and use case; i.e., the shape of a subwoofer attached to a home theater may be different when compared to the shape of a subwoofer enclosure designed for a car audio system.

Also Read: How to build a subwoofer box for deep bass? (Guide)

Parts of Subwoofer (Infographics)

Subwoofer parts infographics

Subwoofer Moving parts illustration (diagram)

This is how coils in subwoofer driver moves diagram

Are all subwoofer parts the same?

In general, almost all subwoofers use similar parts, like the driver cone, coil, magnet, terminals, subwoofer enclosures, etc. However, there may be differences between Active and passive ones.

Active subs have a built-in amp, while passive ones need an external amp.

So, when we compare the parts or components inside a subwoofer, the active subs will have one more component inside, and that is the Amplifier.

Active subs make a great fit for those who want to control the sound and frequency settings without using amps.

On the other hand, passive subs won’t have an amplifier built in, you will need to connect them using an external amp.

Furthermore, active subs have controls and more connectivity options, while passives have basic speaker-level inputs.

So, the selection of a sub depends on your personal preferences and the current sound setup that you have.

Also Read: Subwoofer Placement Ideas for deep bass (Find the best spot)

Final Thoughts

Subwoofers are an essential component of audio systems that bring depth and power to our favorite music, movies, and games. 

Each component inside, i.e., from the magnet and voice coil to the cone and enclosure, plays a crucial role in producing the deep and thumping sounds we love.

So, next time you feel the rumble of a bassline or the impact of an explosion, remember the intricate subwoofer parts working together to deliver those thrilling low-frequency sounds.

Armed with a Diploma in electrical engineering and a remarkable 12 years of expertise, he excels in rejuvenating music systems, washing machines, dryers, and laundry-related appliances. Manish's profound insights and practical know-how establish him as a credible authority in appliance and music system repairs. Contact: manish.singh (at) subwooferblog.com. He's always ready to lend a helping hand!