A Breakdown Of Subwoofer Parts
From the cone to the motor, the subwoofer is made up of delicate yet durable parts. Dissecting and looking at all parts of a subwoofer is an interesting sight, and it helps any audio beginner to understand how they work.
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From the delicate components that produce the soundwaves at the top, to the subwoofer motor that generates all the energy, subwoofers are designed to produce the lowest frequencies, and the vibration and volume that emanates from them is incredible.
You don’t have to know the inner workings of subwoofer parts to benefit from its boom, but if you’re into car audio, it’s a good idea to have a general understanding, as it could help prevent damage. And if they do get damaged, you will have a better understanding of what’s wrong.
What Is A Subwoofer and What Does It Do?
Before breaking down the parts of a subwoofer, it’s good to understand what a subwoofer is. Most people know it’s the big loudspeaker that provides the booming low frequencies, but actually what is a subwoofer and what does it do?
A sub is all about that bass reproduced from low frequencies. It is usually (not always) the biggest driver in an audio set up, because low frequencies need more air. So, the bigger a subwoofer is the more bass it should be able to reproduce.
It’s a specialised speaker that is designed to deliver the lower frequencies from 20 Hz -200 Hz, that traditional woofers can’t produce as clearly.
The low frequencies that we associate bass with come from instruments such as the bass guitar, kick drum, and my personal favorite the double bass. Not forgetting heavy movie sound effects like explosions and other action scenes.
So, what is a subwoofer? In short, it’s an audio driver that makes low frequencies sound better, clearer and louder, and the bigger it is the more it will shake.
The Anatomy of a Subwoofer
The Subwoofer Gasket is a rubber ring or other sealant material that provides a smooth, flat mounting surface to seal the subwoofer to the enclosure.
The Subwoofer Surround is part of its suspension system. The Surround helps protect the subwoofer cone and stops it from being displaced as it moves about when vibrating all that air.
The most common materials Subwoofer Surrounds are made with are either treated foam or rubber, and the preference is usually a personal choice, as there is no “best” out-and-out surround material.
Foam Surrounds rot and don’t last as long, but are more compliant and do a better job of damping the soundwaves. Rubber Surrounds are less compliant than foam, and don’t damp as well, but rubber lasts longer.
The Subwoofer Cone, or diaphragm, is the main active area and one of the main subwoofer parts. When activated by the voice coil, it pushes the air backwards and forwards to create soundwaves.
The Cone design is critical to the performance of the subwoofer and choosing the right material and design can play a big part in the reproduction and durability of your subwoofer.
A Subwoofer Cone works by vibrations from the coil that move the center of the cone. As the frequency and volume gets higher the cone, depending on the material, will start to vibrate differently.
Subwoofer Cones are made from different materials, such as Treated Paper, Polypropylene, Metal, and Fiber, and each material behaves differently, and some are better in some ways than others.
Paper Cones can sound great and generally perform very well. The best thing about paper is that it’s light and stiff, and can be engineered to meet most requirements.
Polypropylene is probably the most commonly used material for subwoofers as it’s cheap enough to compete with Paper Cones, and is more rigid and it helps prevent things like mold, which can affect paper after a time.
Kevlar Subwoofer Cones are a good alternative to both paper and polypropylene. They’re more durable, lightweight, and they’re very flexible. Best of all, the sound reproduction is more precise with kevlar.
Metal Subwoofer Cones are popular too. Aluminum and Magnesium are the most commonly used metals and these cause high pitch resonance and lower frequency. Magnesium is probably better than aluminum as it’s more rigid.
The Dust Cap is a curved dome that mounts over the central hole of the cone/diaphragm. Its job is to protect the inner mechanics from dust. This helps protect the subwoofer from any damage that dust can muster, while also helping the voice coil and the cone perform to their best.
Tinsel Leads are important parts of a subwoofer as they deliver the signal to your driver. They’re the two wires that connect the subwoofer lead ports to the voice coil in the center of the subwoofer.
They require mechanical flexibility and low current-carrying capacity, and they have to be very durable as they endure a lot of vibration as the subwoofer pumps out bass.
The Subwoofer Spider is a flexible corrugated material that is positioned under the subwoofer cone. Its job is to maintain a linear movement of the voice coil, which is placed underneath it, and ultimately helps control the entire cone movement.
Spiders are commonly made of cotton, poly-cotton blend, or conex, but the difference in materials is negligible.
The biggest impact a Subwoofer Spider has is determined by the amount of corrugations they boast. Known as the valleys and peaks, the amount of corrugations, and their height will determine the Spider’s impact on the outcome of the subwoofer’s bass reproduction.
Subwoofer Spider valleys and peaks are important, because the wrong sized spider could potential create ‘spider sag’, which can affect the sound quality of your subwoofer.
The Subwoofer Basket is the frame that holds all the top subwoofer parts in. The rigidity and resistance to resonance of the basket help determine the subwoofer sound quality.
Subwoofer Baskets are usually made from either plastic, stamped steel, or cast aluminum. Plastic baskets are the most used in smaller drivers as they’re cheaper.
Stamped Steel baskets are better in some ways than amluminum as steel helps carry magnetic forces much better than aluminum. However, aluminum draws off heat from other subwoofer parts that heat up quickly, such as the voice coil and top plate.
The Terminals are the positive and negative wire connectors for a subwoofer, and usually protrude from the outer side of the basket. Spring and Ring Terminals are the most popular used, but all terminals as long as you get a good strong connection will do as good a job.
The Voice Coil is one of the most important parts of a subwoofer. It’s made up of three parts: the former, collar, and winding (coil).
The Voice Coil Former is the part of the subwoofer that sits directly under the spider and holds it in place. It’s glued to the coil. the quality of glue used is an important factor in the quality of the Voice Coil.
The Voice Coil Collar is used to strengthen the space between the top of the voice coil winding to the neck joint.
The winding is the tightly wound coil of wire that goes around the collar. This creates the alternating field within the motor structure, and is the current of the magnetic field from magnet to cone.
The wire gauge used for the winding determines the power handling of a subwoofer, and is mostly made of copper, aluminum, or CCA (copper clad aluminum).
There are Single Voice Coils (SVC) and Dual Voice Coils (DVC) and many people think DVCs produce better bass, but they aren’t necessarily better or worse than SVCs.
The main benefits to a Dual Voice Coil is that it should offer more wiring options for connecting to your amplifier. There are no sound benefits to either Voice Coil.
Directly under the underside of the basket and above the magnet, the Top Plate is the first part of the Subwoofer Motor. Its job is to direct magnetic flux to the gap where the voice coil is.
It works along with the t-yoke in creating the magnetic field which sits in the gap between the Voice Coil. Ultimately the flux reacts with the alternating magnetic field from the voice coil, and moves the voice coil backwards and forwards within the gap.
The Subwoofer Magnet is another part of the subwoofer motor and one of the most important parts of the sub. It’s the heartbeat of the subwoofer and where all the energy comes from.
A bigger magnet doesn’t necessarily mean a better subwoofer, but it does play a big role in the quality and volume your sub can reproduce.
The material of a Subwoofer Magnet plays a big role in its quality, but as with most things in the audio industry, there is no out-and-out best material.
Subwoofer manufacturers use different materials depending on the sizes and the tones they want to reproduce for the magnet in the subwoofer motor.
Neodymium has the greatest field strength of any other magnet material, and subwoofers made with these magnets will have a good frequency response. Another good thing about Neodymium is because they’re so strong, a smaller magnet can be used to reproduce volume of other materials’ bigger magnets. This allows for a smaller size and weight – good if you’re limited for space. The biggest problem with neodymium is that these magnets are known to shatter easier than other materials.
Ferrite magnets are also common, but ferrite weighs more and maintains its magnetic strength over time better than other materials. Probably the winning ticket for subwoofers with ferrite magnets is they usually sound better than other materials as you crank up the volume.
Alnico is an alloy material that is used in some subwoofers. Made up of aluminum, nickel, iron and cobalt, Alcino is tougher than other magnet materials. The biggest problem with Alcino is that it can lose its magnetism more readily than other materials.
Samarium Cobalt is another material used for Subwoofer Magnets. This material is more expensive than other materials, but it boasts the strength of neodymium, and protects itself better against corrosion from natural elements.
T-Yoke (Bottom Plate)
The T-Yoke is another part of the subwoofer motor. one that is underestimated as it helps drive the magnetic fields to the driver and keeps the subwoofer from overheating.
The T-Yoke is the bottom plate of the motor structure and also an attached pole piece that that extends up to the center of the voice coil.
Along with the top plate, it creates the opposing force from the voice coil, which helps move the voice coil backwards and forwards.
Ventilation is allowed through the gap in the pole piece and a pole ring as the air moves back and forth, helping cool the voice coil down. As well as this, the T-Yoke acts as a heatsink by pulling heat away from the voice coil and keeping the subwoofer motor cooler.
The Parts of a Subwoofer Dissected
So there you have it: the anatomy of a subwoofer. From the Subwoofer surround and the cone that produces all the boom, to the subwoofer motor that generates all the energy the cone can produce, a subwoofer is a delicate yet durable piece of audio equipment.
As mentioned throughout the article, some parts are regarded as the most important subwoofer parts, but really they all do their job and are important. Without each part the power handling and the sound quality a subwoofer produces would be hindered.
And as with everything else in the audio industry, there is no single best material for each part of the subwoofer, and that’s why it’s important to do some research before you invest in any aftermarket audio equipment.