Replace Subwoofer Voice Coil in 9 easy steps

Voice Coils are one of the most essential components of Subwoofers and Speakers when it comes to the production of sound.

One can also call a voice coil the Heart of the Subwoofer because of its linear motion. The back-and-forth movement of the voice coil activates other active parts such as the cone, spider, and surround.

All the moving parts contribute to producing sound waves of different frequencies.

Being a physical component of the subwoofer there is a chance of being worn out or burned out for many reasons.

Let us discuss below the various reasons that cause damage to the voice coil along with the possible solutions and replacement steps.

Blown subwoofer voice coils: Causes and Solutions

To prevent premature damage and burns to the voice coils it is better to use and maintain them properly by following a few tips.

Excess Sound Levels

The sounds that we actually hear, are typically a combination of vibrations and the surrounding air.

On higher volumes, the vibration level is always on the higher side, especially the low-frequencies (Bass) handled by a subwoofer.

Louder volumes put a lot of stress on the subwoofer parts if you constantly play boom bass music for too long most of the time.

Solution: Hence, playing your favorite music notes mostly with a little reduced volume and up to your satisfaction level is always advised.

Constant Playtime

Playing subwoofers for a longer time without giving them room for cooling down can cause overheating issues.

Subwoofers produce low-frequency waves with the help of a few active parts including the voice coil. These functional components move constantly when you put your music to play.

With constant movement, the voice coil is especially prone to burnout due to excess heat like any other part of an electronic device.

Solution: Avoid playing musical notes with extreme bass effects for too long and too frequently. This will allow some resting time for the active parts of the subwoofer to cool down.

Improper Power Supply or Power Surges (fluctuation)

If the power supplied to the subwoofer fluctuates way beyond or below its requirements it can lead to damage to the internal parts such as built-in amps including the voice coil.

Due to constant and intense power surges can result in a malfunctioning amplifier. This can further lead to uneven electrical flow supplied to the voice coil through the terminals. It can lead to uneven vibrations and cause damage to the voice coil.

Solution: Avoid using your sound systems, in fact, any electronic device in the event of heavy fluctuations in the power supply to your home.

These are rare but can occur in unforeseen circumstances such as during monsoons, extreme windy conditions, etc,.

Amplifier overpowering the Subwoofer

If you are using an external amplifier which is double or triple the power of a subwoofer then there could be a problem.

Although, more powerful amps have a very low impact on loudspeakers but can have a big impact on the subwoofers or bass speakers. This will eventually result in damaging the parts of the subs.

Typically, when the RMS and Peak Power Rating don’t match up between the amplifier and subwoofer can result in an overpowered subwoofer.

Solution: Always make sure to connect amps of similar or suitable specifications to the subwoofer. If you are unsure about the proper match make sure to consult with a professional before adding subs and amps to your music system.

Under-scaled or Weak Amplifier

It happens with many people that they opt for amps that are under-scaled or of limited power.

A weak or low-wattage amplifier can be hazardous for your sound system as it will lead to power destabilization. This may further result in the supply of direct current to the subwoofers and speakers.

The voice coil bears the more significant impact and can lead to burnout or going off track.

Solution: It is always best to opt for amps that meet the specs of your sound system requirements in terms of wattage.

Distorted Audio

Playing music with distorted audio signals in it can lead to an overdriven voice coil. This is not a good sign because overdriven voicer coils are prone to overheat and melt.

Solution: If you find distortion in a specific music file avoid playing it to prevent the voice coil from being overdriven.

Improper Connection

Another significant issue is incorrect or loose connectivity of electrical wires to the terminals and voice coils.

If you look at the image below it has two points released off the voice coil positive (+) and negative (-) that need to be connected correctly.

Improper terminal connection

It may look as easy as plug-and-play for many, but poor or incorrect contact between the electrical wires’ positive (+) and negative (-) terminals can result in a burst of amplifier distortion.

It will result in an uncontrolled volume, which can be too aerated at the initial stage of the music played on the subwoofer.

Hence, improper connections are responsible for causing damage to the voice coils of your subwoofer or even blowing out the entire unit. This is especially, applicable at high levels of wattage (electrical power).

Environmental Factors

Environmental factors such as exposure to extreme temperatures or humidity, moisture, etc., can degrade the subwoofer parts including the voice coil over time.

Solution: You should always avoid positioning your subwoofer from being exposed to extreme temperatures that can impact the unit.

Aging

Aging is the only factor that deteriorates almost every man-made product in a specific period of time. So does the subwoofer and its parts damage over time. And, one barely has some control over the fact, however, you can at least prevent them from premature damage.

Solution: You can’t call it a solution but can take it as a suggestion. As a golden rule, always make sure to use them carefully and ensure maintaining them in a timely manner.

In simple words use your subwoofers wisely so that they last longer.

How to test the Subwoofer Voice Coil?

You can test your Subwoofers voice coil in several ways such as using a multimeter, physical inspection (cone pushing and internal inspection), and through sound testing.

Let us go through the various testing methods of a blown subwoofer coil.

Test a Voice coil: Using a Multimeter

With the help of a multimeter, you can check the ohm or the reading response of the voice coil.

Multimeters have two points positive (+) and negative (-) that need to be connected to the terminals of the voice coil where the tensile leads connect.

Testing a Subwoofer Voice Coil using Multimeter

Let’s look at the steps below to test the subwoofer’s voice coil using a multimeter.

  • Unplug the subwoofer from power and unscrew the frame or basket from its enclosure to remove it.
  • Once the subwoofer basket is out from the enclosure you will be able to locate the internal parts through the frame’s gap.
  • Additionally, if applicable you can also try removing the subwoofer grill carefully for better access to the internal parts.
  • Before using the multimeter simply inspect the voice coil for any physical damage, misalignment signs, or wear-outs.

If that looks fine then simply use the multimeter for testing the reading of the voice coil.

Setting the multimeter - Testing a Voice Coil using Multimeter
  • Set the multimeter to the ‘ohms’ setting.
  • Place the leads of the multimeter on both the terminal points of the subwoofer voice coil.
  • If the multimeter shows readings within the normal range, it should be fine.
  • Otherwise, if there’s a shallow reading or no reading, it simply means the voice coil is blown and damaged. It will need a replacement.

Testing a Voice Coil: Physical Inspection

Physical inspection is usually done by looking at the voice coil for any physical damage and gently pushing the cone a few times.

Test a voice coil by Cone Pushing technique

You can try to determine the status of a voice coil by pushing the cone of the subwoofer.

Start from the outer edge of your subwoofer’s cone by placing your hand firmly.

Next, start pressing it toward the center in an even manner and without rushing.

subwoofer voice coil cone pushing technique

Repeat the step a few times.

Try to notice any rubbing or resistance sound as you press, move, and release the cone.

You will need to listen carefully in a silent area to notice such sounds while performing the cone-pushing test. If you notice such a sound it may indicate damage to the magnet’s structure or a damaged voice coil.

Inspect the voice coil visually

The visual inspection requires detachment of the subwoofer bracket from its mounting bracket.

The step is similar to testing a voice coil using a multimeter where you first observe the physical appearance of the voice coil.

It can be done by removing the subwoofer from its enclosure by simply unscrewing it. You will have access to the voice coil and connected parts through the frame’s gap.

If the voice coil has signs of wear-outs or if it’s misaligned you will need to fix it accordingly or replace it depending on the cause of damage.

How to replace the Subwoofer voice coil?

If the voice coil of your subwoofer has been damaged to an extent where repairing it won’t work, then replacement remains the only choice.

You can repair minor wear and tear using the right tools or replace the voice coil to get the desired output from your subwoofer like before

Let us quickly look into the steps below to replace the voice coil of your subwoofer.

Step 1: Disconnect the subwoofer from the power source and other connections if applicable.

Step 2: Unscrew and remove the subwoofer bracket from the enclosure.

Step 3: Remove the dust cap and surround if required. In most cases detaching the cone does the job of reaching out to the voice coil.

You will need a sharp object such as a knife or a fine cutter to remove the cone from its edges.

Note: Be careful while working on the edges of the dust cap, cone, and surround.

Step 4: Now you will have access to the voice coil which can be removed by unscrewing the screws holding the coil. Secure the screws in a bowl.

Step 5: Gently, pull the old voice coil out of its assembly.

Step 6: For your satisfaction physically inspect the voice coil and test it using a multimeter for continuity. If it fails to respond to the testing then proceed by fixing the replacement voice coil to its assembly.

Step 7: You can also test the new voice coil with the multimeter to make sure it isn’t faulty. Next, align the voice coil properly with the adjoining parts and to its assembly.

Step 8: Connect the terminal wires and start fixing the components back.

Step 9: Once you reassemble everything you can test the subwoofer’s sound quality to ensure the replacement part and the steps were successful.

In most cases, you will get a re-coning kit that helps in replacing the cone and the voice coil together using similar steps.

Subwoofer Voice Coil Maintenance Tips

The best way to protect the subwoofers and their parts including voice coils from premature damage is to use and maintain them properly.

Let us quickly go through a few tips below which will help in maintaining your subwoofer’s efficiency in the long run.

  • Make sure to play subwoofers with moderate sound and not too loud all the time.
  • Avoid playing subwoofers frequently for longer durations and allow them to cool at regular intervals.
  • Do not play music notes with distorted signals in them to prevent the moving parts from stressing too much including the voice coil.
  • Place your subwoofer in a secured area and away from exposure to extreme weather and climatic conditions.
  • Do not overpower or downscale your subwoofer with amps that aren’t suitable or support the specs of your subwoofer.
  • Always make sure the connections to the subwoofer are right internally and externally both.
  • Avoid the flow of direct current to the subwoofer.
  • Turn off the subwoofer and unplug from the power in the event of heavy power surges.

Following the above steps will help maintain the efficiency of your subwoofer and its parts for years to come.

Final Thoughts

Voice coils in subwoofers convert electrical and magnetic energies into mechanical energy. This is how the parts move to generate pressure waves and output them in the form of sound.

It is very important to consider many factors to prevent the voice coil and other parts of the subwoofer while you play music of different genres.

Overpowering a sub and tuning your bass-heavy music to the loudest frequently can cause a lot of stress on the voice coil and other active parts of the subwoofer.

A damaged or burnt voice coil can be difficult to repair and hence replacement becomes the best choice.

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!