Why Do Speakers Blow? The Answers Might Shock You

By Brian Casey

Why_Do_Speakers_Blow

It is heartbreaking to drive while listening to your favorite music and after some time you realize that your speakers are dead or no longer sound properly. There are so many causes that can be related to speaker failures. All these causes can generally be classified into mechanical and thermal or electrical failures.

In a nutshell, mechanical failures occur when the cone is made to move further than its original designed position. This is normally due to a high power supply which results in high vibrations. On the other end, thermal failures are caused by a high power supply which overworks the speaker. It gets overheated, and eventually, the voice coil components burn or melt down.

Concurrently, there are other causes that might get speakers blown for instance the age of the speakers. Why do speakers blow? There are several answers to this question. Speakers that were made using inferior materials are likely to blow out as they age.

For you to deeply understand why speakers blow or how to avoid blowing speakers, we will need to dig a little deeper by finding more about speaker blow out.

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Is Distortion a Signal of Blown Speakers?

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The dirty truth about distortion is that it does not signal if a speaker is blown out. Distortion is the ability of the speaker to detect inaudible signal.  Mostly it comes from the signal itself, not the speaker. It is mainly caused by detection of “clipping’’ signal.

Clipping is the point at which an audio device can no longer supply enough voltage to correctly and purely amplify the audio signal. Clipping can occur anywhere along the signal chain; it can be at the signal processor, amplifier or the source unit.

It is; therefore, wrong to conclude that your speakers are blown out based on distortion. The best way to go is to examine the speakers for symptoms like burned voice coil or damaged cones.

What are “blown out” car speakers?

Sometimes blown out car speakers can be confused with incorrectly connected or equalized speakers. The speakers may sound distorted not because they are blown but because they are not well connected or equalized.

First, you might need to do some testing of your connection to find out if your speakers are really blown out. Blown out speakers are speakers that have failed to work or sound bad despite having correct connection. If a car speaker is fully blown out, then it won’t relay any sound.

A second case, if a speaker is blown, then it means that it will relay buzzing sounds instead of continuous clear music. For partially blown speakers, hearing crackling, hissing, fuzzy or static distortions is common.

Why do speakers blow out?

As we mentioned earlier, there are two main causes of speaker blow out; Mechanical and thermal or electrical causes.

Mechanical Failures 

Overpowering

Mechanical failure occurs when a speaker is overpowered especially at low frequencies where the cone is not supposed to move too much. At high power, the cone moves in a way that it is not designed to move. When the cone moves too much, it will lead to material stress.

The material stresses cause the parts to collide with each other.  The material will tear, loosen or break. This will distort as the electrical signal is being converted from electrical to sound frequency signal. The result will be a partial or permanent damage.

Improper Enclosure

Another cause of mechanical failure is improper enclosure size.  This mostly applies to subwoofers. Large enclosures will compromise the mechanical suspension of the speaker, making the surround to tear apart.

This will lead to a separation from the speaker’s frame and eventually result in permanent damage. It is always recommended to make the enclosure stay in between +/- 25% range of the manufacturer’s recommendations of the enclosure volume (Vb).

If smaller enclosures are used, there are chances that there will be power handling effects. These effects may not affect the subwoofer’s mechanical performance as compared to using large enclosures. Going for smaller enclosures will be a safer way to go for you.

Improperly Vented Enclosures

This is another main cause of subwoofer mechanical failure related to tuning. Improper tuning may cause mechanical power handling capabilities of the speakers to go below that of the required tuned enclosure frequency.

When installing or building the subwoofer venting enclosure, it is required to check the Pd (Port diameter) and Pl (Port length) about the Vb (Internal Volume) as recommended by the manufacturer.

Wrong Crossover

Mechanical failure can also be caused by the use of the wrong crossover. For example, if low frequencies are directed to the tweeter channel. If such a mistake is made, the tweeter cone will delaminate leading to permanent damage. To avoid this, it is advisable to follow the manufacturer’s guidelines.

Electrical Failures

Overpowering

Blowing out of car speakers due to overpowering is mainly a result of using too much power from the amplifiers. When high constant power is supplied to the speaker, the voice coil is overworked which leads to the generation of too much heat leading to melting and eventually permanent damage as a ‘burn.’

This normally affects subwoofers, midrange speakers, and tweeters. The only way to avoid this is to reduce the amplifier gain as well as reducing treble or bass settings. Most of the time, what is really confused with a blowout is distortion. If it happens that you hear distortion of your speakers before reaching peak volumes, it is important to check the amplifier settings.

You will need to readjust the amplifier bass or treble knobs or even the master. Another thing to check is the signal processor’s controls, for instance, the gain control. Also, check the equalizer. How are the bass, mids and the high frequencies separated? The bass frequencies should be channeled to the subwoofers, while the mid to midrange drivers and the highs to the tweeter.

High Volumes

High volumes mean that you are supplying more electrical power to the speaker so that it can amplify the frequency gain of the sound coming out of the speaker. This will lead to the overpowered voice coil. When voice coils are overpowered, they burn and lead to permanent damage “blow out.”

Other Causes

Improper Designed Sound Systems

 systems that are not properly designed have high chances of blowing up after some time.

Amplifier Clipping

Speakers with dedicated amplifiers commonly experience the problem of clipping that may lead to blowing out. This problem is experienced when the amplifier is overdriven making the bottom, and the top audio waveforms to be clipped off.  If this phenomenon occurs, the speaker damage is likely to occur since the speaker is being supplied with too much power.

Physical Damage

Careless installation or handling of speakers can cause blowouts as well. This normally occurs when the speakers lack protective grills. The cones are likely to be torn or pierced since they are the most delicate part of the speakers. Try to find a protective grill for your car speaker if yours lacks one.

Age and Normal Use

It is pretty possible to find speakers that fail due to normal use or age. This normally happens to speakers that use the inferior materials. Factory speakers normally suffer from this effect. If you own OEM speakers and they have recently blown out, it is good to replace them with high-end aftermarket speakers.

How to Tell If Your Speakers are Blown out

So, how are you going to tell that your speakers are blown out? Here are two ways that you can tell if your speakers are blown out;

  • Check for Continuity

For you to check for continuity, you will need to remove anything that bars you from accessing the speakers. You will need to remove the panels, grille, door panel and any other component that is necessary to be removed for you to access the speakers.

Disconnect the speaker wires and then check for continuity using a multimeter by making a connection between the two speaker terminals. If the speaker is blown, it shows no continuity.

  • Rule out Possibilities

This method will require an audiophile who has a trained ear. Look for a familiar music; make sure that the music does not cover most of the spectrum since it will be hard to tell what is going on.  

With your favorite track playing, you will begin the diagnosis by setting crossover controls at zero or neutral levels. By doing so, you will be able to tell whether your speakers are working out of range. If you can capture a defect among the speakers, you can now begin to narrow your search down until you find the source of the problem.

Final Words

Why do speakers blow? This should now be something familiar to you. Now you know why speakers blow out and many more things that are related to speakers blowing out.  Besides knowing why speakers blow out, you can find out and tell which one has blown out.

You probably now know how not to blow speakers. We hope that this post has been of great help.  Please share it with your friends so that they can also gain from it.

About the Author

Here at Car Speaker Land we have only one goal: to bring you the best speakers around. Well, actually we have two goals: we also want to make sure that you’re able to get things going without having to pay the steep fees which are often charged for even the most basic procedures in auto shops.

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