How To Tell If A Subwoofer Is Blown

Has your speaker started to make gurgling noises? Maybe your speaker just doesn’t sound the same as it used to, there’s a chance that your subwoofer is blown and could need repair.

A subwoofer or sub is an audio output that reproduces the low frequencies of bass which operate at around 50 – 1000 hertz.

A subwoofer is rarely used on its own, a subwoofer is used to enhance the lower frequencies of the bass with the help of drivers in addition to a left and right speaker which generally reproduce the higher frequencies.

A driver is the physical component of the subwoofer that modulates how the sound wave feels in the ear drum. Next time you see a subwoofer watch how the driver vibrates and changes as it is fed soundwaves, this will be identical to how your eardrum looks.

The movement that occurs in the driver will be identical to how your eardrum moves when interacting with the same sound. So, if you imagine that your eardrum is burst you wouldn’t be able to receive low frequencies, this is what happens when a subwoofer is blown.

What Causes The Subwoofer To ‘Blow’

When people say their subwoofer is ‘blown’ it typically means that the driver is broken in some way, so when the low frequencies hit the driver the bass can’t be heard and the broken driver often vibrates in a way which causes an unpleasant sound.

This often means that the speaker cone has literally burst and there is physical evidence of that damage. 

If you play music too loudly for too long, or the sound waves are analyzed in a way which causes them to peak aggressively, you could break your driver and blow your subwoofer.

The physical capabilities of the speaker have been working excessively hard and reached a point where they can’t take it anymore and the material ruptures – much like an ear drum.

Distorted signals also cause subwoofers to blow. This is troublesome as unless you are an audiophile or sound engineer it can be hard to hone in on what a distorted signal actually is.

In most cases it is simply a bad signal that we turn up in an attempt to make it better quality which in turn causes irreparable damage to the speakers hardware.

How To Diagnose If Your Subwoofer Is Blown

There are a few different ways to tell if your subwoofer is blown, and can help you understand how bad the damage is, and which component needs replacing.

Physical Inspection

One way to tell if sound is coming out of the subwoofer is to place your hand on it and feel for the vibrations. One important thing to take into consideration is what surface your speaker is on.

The most optimal material for a subwoofer to be on top of is wood. If your subwoofer is on a plastic box or a surface that might have something loose on it that could rattle, then this could be the issue rather than the speaker being broken.

 This also can also help diagnose if your speaker is broken. A functioning subwoofer moves which is both physically visible to the eye and something you can feel with your hand.

If the speaker cone is moving and vibrating but making an unpleasant sound then you may have blown your speaker and this may simply require the drivers to be fixed.

If your speaker cone is rigid and not moving at all then your system is likely broken, and this will require components to be replaced or electrics to be rewired.

In the worst case scenario your actual speaker cone might have literally blown which means that the surface will have been ruptured and there could be a literal hole which you need to identify and replace. 

Audio Inspection

A blown subwoofer will produce strange noises, as the drivers are broken which modulate how the speaker receives low frequencies. Start audio playback at a low volume and slowly increase it until you can hear an audio defect.

The audio defect will sound heavily distorted, people often refer to this colloquially as ‘farting’ or ‘gurgling’ as it sounds similar. Make sure you test this with different audio files as some tracks may intentionally be using a distorted sound.

If sound comes out, but the audio defect occurs when the bass comes in, then the subwoofer is blown. If there is no audio being outputted then this could simply be an electrical problem.

Voltage Inspection

A digital voltmeter will give you direct readings of the subwoofer’s voltage. This tool will help you identify if the issue is a broken component or an electrical issue. If there is no voltage, then your speaker will have an electrical issue that will need to be fixed.

If your speaker is outputting a voltage which is lower than the expected voltage indicated in the users manual, then this will diagnose that your subwoofer has been blown or that one electrical component of the system has broken as it is no longer outputting voltage.

What To Do If Your Subwoofer Is Blown

If you have diagnosed what the issue is with your subwoofer then there are a few paths you can follow.

A good thing to check is your warranty, if you have recently purchased the speaker then you could still have a valid warranty which means your product can be replaced for free.

If you know exactly the component that has broken then you could buy a new component and potentially repair it yourself, although this can be a bad idea if you aren’t properly trained as you could damage the speaker even further.

The best thing to do if your speaker doesn’t sound right is to take it to a sound engineer who will be able to diagnose the issue for you and repair the speaker in return for money.

The money you pay for repair will be decided by what component has broken as the engineer will have to buy the component that needs to be replaced.