Why Do Car Speakers Blow and How to Prevent It?


I am sitting in my garage looking at a blown car speaker, and I am thinking to myself, why do car speakers blow?  

Two main reasons that cause car speakers to blow are mechanical or thermal failures. Mechanical failures occur when the cone moves further than it was designed to. In other words, the voice coil due to being temporarily overpowered starts vibrates faster and with a more extensive range of moves and causes the cone to break.

The thermal failure is caused by constant overpowering of the speaker that causes the voice coil to either burn or melt.

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In the article below, you will find more details about the causes of blowing car speakers, and we will explain how to avoid blowing out car speakers.

How do I tell my speaker is blown?

It is not always easy to tell right away if car speakers are blown when they make strange noises or do not react to the signal. If you are wondering what a blown car speaker sounds like, well, it depends on the speaker and type of the damage.

why do car speakers blow

Any kind of damage that causes the speaker to rattle, make sound blurred, or create strange noises, can result in blown speaker. But how do we check if a speaker is blown?

Below are common signs of blown car speakers:

The speaker plays music, but the sounds are distorted.

If you hear such weird noises, it may mean that one of your speakers is damaged. Try to reduce the volume and listen carefully to the sound quality. It is essential to listen to high-quality music, preferably from a CD, because mp3 or other file types are often highly compressed and do not offer the highest sound quality.

If you hear that sound quality gets worse aligned with increased volume, you have to locate the damaged speaker using fader and balance functions in your head unit. In most cases, you will find that a faulty speaker is partially blown and has a loose or damaged voice coil.

Music sounds are mixed with popping, rattling, or buzzing sounds.

Hearing these types of noises, together with music, is a sign of severe speaker damage.

Although crackling may be caused by damaged wires, to make sure what causes the issue, you have to find the troublemaker. If the cables are okay and the speaker still makes such noises, it is likely to be blown.

To double-check, whether wire or speaker cause the problem, the easiest way is to swap the left speaker with the right one. If you hear the same speaker making weird sounds, when connected to the other side, you have a blown speaker. However, if you hear crackling coming from the same place, but from a swapped speaker, you have to check wire because your speaker is good.

We hear only partial tones

When you hear the music, but some tones are missing, for example, the only sounds you hear are bass, or only treble, your speaker can be partially blown. Try to balance different tones on the equalizer, and if you do not hear a full range of sounds, but used to play well, prepare yourself for its repair or replacement.

No response from the speakers to the signal

This is a common sign of a dead speaker. If your speaker does not respond to the audio signal and you do not feel any vibrations when touching the cone, your speaker is blown.

In this case, I recommend swapping speakers to eliminate the wiring problem, especially in older cars. If, after swapping the speakers, the same one is silent, it means there is no closed circle through the voice coil, and the speaker is blown.

In each of the above cases, we have to cross-check the faulty speaker to determine if it is really blown, and we should check both impedance and continuity.

Correctly functioning car speakers have impedances depending on the model, either 2, 4, or 8 ohms, and if the speaker is good, the measured value shown on the multimeter should be similar. If you see on display very high or sometimes infinite impedances, the speaker is blown.

When checking continuity, make the same connection to the speaker terminals, and if multimeter shows no value, your speaker will be replaced or repaired.

Why does my car speaker blow?

In many cases, when a car speaker has been damaged, we can hear people saying that the speaker has blown. But what exactly is a blown speaker, and what causes it?

If the speaker has blown, it either has stopped working entirely or its sounds that used to be good, suddenly deteriorate. The main reasons for speakers to blow are mechanical or thermal (electrical), which prevents the speaker from working correctly. 

Mechanical problems usually occur when the speaker cone’s movements are larger than should be, while thermal failures happen when internal parts of the speaker burn or melt due to being overpowered by the amplifier.

In addition to the above, we can damage speakers by listening for a long time to the music that is too loud or when speakers are old and internal parts are not as strong as new. This happens most often to the factory car speakers that are made from low-quality materials.

Below are the most common causes of blown car speakers:

blown car speaker

Overpowering car speakers

In speakers that receive too much power, the voice coil will force speaker cone to excessive moves, which is especially dangerous at the low frequencies.

When the cone vibrates and moves too far, it causes stress at the cone’s connection with the suspension and surroundings. As an effect and if forces are too high, the weakest material will tear or break.

Most damage happens to the paper cones, causing music distortion and crackling sounds from the speaker. In extreme cases, when the cone’s connection with either suspension or surroundings has been entirely damaged, the speaker stops working completely. 

Clipping amplifier

Clipping caused by a too weak amplifier that tries to create higher sound waves than is capable of can cause tweeters that do not have a top frequency limit to blow. 

Volume set too high

Listening to too loud music creates a large energy supply to the speaker. If the speaker receives more electricity than can handle, this can cause overheating thin voice coil wire. An overheated voice coil can either burn or lead to melting other sensitive speakers’ elements, for example, the glue that connects the speaker’s suspension with the cone. This, however, can rarely happen and often in the systems with amplifiers overpowering the weak speakers.

More dangerous for the speakers are playing them too loud when the amplifier is not powerful enough to power the speakers.

For example, if we have 300W RMS speakers and a head unit or small 50W amplifier powers them, we often do not hear the music’s expected dynamic. As an effect, we turn volume up to the maximum. This, however, does not help. We hear distorted sounds because speakers are begging for more electricity, but the amplifier cannot supply more.

If this is happening and our amplifier is too small, we will hear loud but mediocre music quality with distorted sounds, or in the worst case, the speaker will blow. The speaker’s weakest part will be destroyed because of the large and unstable voice coil vibrations.

Incorrectly set crossover’s pass filters.

Wrong or incorrectly set crossovers also cause speakers damage. Especially affected are tweeters, which receive frequencies that are too low for them. 

When tweeter tries to play low frequencies, vibrations of the sensitive cone are way too high, which causes the cone to delaminate, and permanent speaker damage.  

Speaker is mounted in a too large enclosure

The speaker enclosure’s wrong size is another common cause of blowing speaker, and this does not apply only to the subwoofers, but also to the speakers installed in car doors.

Enclosures that are too large do not create required pressure, and as an effect, significant and unstable cone movements can damage the speaker’s surround. The same can happen to the door speakers when we listen to loud music. 

When you build a bass box for your car, remember to follow a recommendation from the speaker’s manufacturer regarding the box volume. It is better for the speaker when the enclosure will be a little too small than too large.

However, when your enclosure is way too small for a particular speaker, the voice coil may overheat because of the cone’s limited movements caused by the high air pressure in the box.

Can I fix the blown car speaker?

We can try to repair any speaker, but repairs of blown speakers are complicated, expensive, therefore not always cost-effective. People decide to repair speakers usually when they are costly or unique, because it may be difficult to find a replacement speaker.

Replacing voice coil or suspension is complicated, and if not done correctly, a sound effect after refurbishment will not be satisfactory. Therefore these refurbishments should be left for professionals.

However, if you want to repair a blown speaker yourself, you may need to use a repair kit containing the original components of the damaged speaker.

There are also simple repairs of car speakers that can be done at home. These are, for example, replacing the speaker’s surround or repairing the cracked cone. If you would like to learn more about the speaker’s repairs, this article will show you step by step how to repair the broken speaker’s cone.

Repairing the speaker is not everything. More important is to find the reason for the speaker’s damage. Speakers do not blow during normal working conditions, and if we do not remove the source of the problem, the same can happen to the repaired or new speaker in the future.

How to replace a blown car speaker?

When car speakers are damaged, especially original factory speakers, it creates an opportunity to replace the speakers with new, so we can enjoy listening to better quality music for a long time.

If you want to replace the speaker with a new one, you should replace a pair left and right, and it does not matter if they are in front or the back of the car.

The sound quality from factory speakers decreases over time, and if you replace only the blown speaker, you could hear the difference between left and right. Based on the experience, and not only mine, I recommend always to replace the pair of speakers.

To replace blown car speaker (or the pair including the damaged speaker), we have two options:

Purchase original factory replacement speakers.

Although it is the most straightforward method, we will not increase sound quality in the car. Sound will remain at the current level because most factory speakers do not offer fantastic music experience.

Replace blown factory speakers with aftermarket alternatives.

Aftermarket speakers have better quality, and in 99% of cars, they will sound better than the original models. Below are few other benefits of the aftermarket speakers:

  • They are more powerful
  • Have higher frequency response
  • Components of aftermarket speakers are made from better quality materials, that affects very well their durability and lifetime.
  • Aftermarket speakers offer a large selection of types

The remaining 1% of cases, where aftermarket speakers may not sound better than factory speakers, apply to cars equipped with the hi-end car audio systems, for example, Bentley with Niom system or Maserati with Bowers & Wilkins.

In such cars, blown speakers should be replaced only with the original ones. Besides, these cars have systems built in many cases with over 20 speakers, so it would be extremely difficult to find direct aftermarket replacement.

It is essential to find out which speakers will fit our car. They have to have the right size, depth. Also, their power has to be aligned with the amplifier or head unit. If you decided to buy speakers with larger depth than current ones, you will have to buy adaptors or distance rings to make sure the magnet does not touch metal door panels, and windows open freely.

You may also need to purchase wires connection cables to attach them to the cubes in factory installations.

When buying aftermarket speakers, make sure you listen to at least several different types and choose these with the sound type you need. Over the years, I read hundreds of reviews, but when I listen to these “top” or “best” recommended speakers and test them in different configurations, well…. I am not sure about their performance, but this is my individual opinion.

I am pointing this out because every speaker sounds differently, and listening to them before purchasing is critical.

When you have completed all the needed equipment, now you need to install the speakers, connect the wires, and put the door panels back in place.

How to prevent car speakers from blowing?

It is not always possible to keep car speakers from blowing because many reasons can cause this damage, but we can reduce the probability of car speakers to blow.

Many speakers blow because their power does not match the rest of the audio system, or the set-up of the car audio is incorrect and causes damage to the most sensitive part of the speaker, which is voice coil.

When a voice coil is damaged, there is very little chance to repair such a speaker.

Below are a few simple rules to follow that will reduce the probability of speakers to blow and increase their lifetime.

how to protect car speakers from blowing

Use correct passive crossover, or make proper set-up for active crossover.

Crossovers for systems speakers should match the speakers’ frequency and their power. When using active crossover, we have to remember correctly set frequency that will be cut and not transmitted further to the speaker.

A good practice is to set the crossover’s frequency slightly higher than the manufacturer’s recommendation because the information in the speakers’ technical specifications does not always reflect the actual condition in which speakers work.

For example, when we read that the speaker works from 60 Hz, do not precisely set the crossover at 60 Hz, but higher, like 70Hz or 80Hz. This will reduce the speaker’s probability of blowing when playing high volume at the lowest possible frequency and will increase the speaker’s lifetime.

You can compare it to driving a car at the maximum engine’s RPM. We do not do that to the engine, even when you take a car to the race track, you do not keep it nonstop at the maximum RPM.

The same for the car speakers, they should not play top or bottom frequencies at the high volume.

Do not overpower or under power the speakers.

Overpowering or underpowering car speakers apply to the majority of car audio systems and affects all types of speakers, from heavy subwoofers to little tweeters.

The easiest way to avoid supplying speakers with the wrong power level is to use an amplifier that matches speakers. Ideally, RMS of the amplifier is 50% more than the RMS of the speaker.

For example, if we have a 100W speaker, an amplifier should produce no more than 150W per channel. Make sure to check continuous RMS power, not any other irrelevant type.

Having an ideal power ratio between speakers and amplifiers is, however, not always possible. When your amplifier is much more powerful than it should be for a particular speaker, its power should be reduced on the steering panel.

Much more dangerous for speakers are amplifiers that cannot produce enough power for the speakers. If this is a case, you have to be careful with turning up the volume because this can cause your speakers to blow in no time.

If you do not want to stop listening to loud music, the right way to do is to buy a stronger amplifier. This will protect your speakers from being destroyed, and allow them to play with the much better and clear sound quality for a long time.

Prevent speakers from physical damage.

The grill should always cover cone in every car speaker. This is especially important for a subwoofer in the trunk. If you want to keep your speakers in good condition, do not place next to them anything large or sharp that could damage or reduce cone’s free movements.

Use the right size enclosure.

This also applies mainly to the subwoofers. Make sure the subwoofer box is not too large. Otherwise, too high vibrations of the cone can destroy the speaker’s surroundings or suspension. It is better for the speaker when it is placed in the box that is too small than too large.

Martin

Welcome to ImproveCarAudio! I am Martin, and I love to write about everything related to car sound systems. I strive to provide the most accurate and helpful information about car audio through extensive research, as well as my experience with car audio installations.

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