If you are suspecting your subwoofer is blown, there are a couple of signs that will tell whether or not this is true.
Before you even take it to a technician for repairs, be sure to check for the following 4 signs of a blown subwoofer.
The Cone is not Moving
The speaker cone is one of the components that will tell you whether or not it is blown. On a normal speaker, the cone usually moves in and out as the music plays.
The vibration of the speaker cone is what pumps sound waves into the surrounding atmosphere, making sound audible to your ears.
However, this is not the case for a blown speaker. The cone tends to remain in one place; hence no sound is produced without vibrations.
You can check for this by physically inspecting the sub. Simply remove the mesh speaker cover to reveal the cone underneath. Using both your hands, try to push in the cone and see what happens.
If the cone does not move despite you pushing it, or if it moves further than it is supposed to, the speaker is likely blown.
But even if it moves like it usually does but the sound is distorted, the subwoofer may still be blown.
Another sign that your subwoofer is blown is poor sound quality. You will notice that your system is producing an unusual sound when you turn it on.
In most cases, the sound might be piercing and “scratchy”; generally unpleasant to listen to.
The distorted sound may not be noticeable at low volumes but it will get more evident as you keep turning on the knob. The higher the volume, the greater the distortion.
So, once you’re sure the sound coming from the sub is uncharacteristic, there is a possibility the speaker is partially blown. On the other hand, if there is no sound at all, then the subwoofer is fully blown.
This is one of the most common indicators that your sub is blown. You should be able to tell this when you try to play a song and no sound is produced.
But the lack of sound doesn’t necessarily mean that the subwoofer is blown; sometimes, it may be the result of a damaged audio-carrying cable.
In this case, your sub may be safe and sound, only that there is no sound signal getting to it from the audio source; hence the lack of audio.
However, if your audio system is receiving both the power and audio signals and not producing any sound, chances are that it is blown.
Unstable Ohm Reading
A simple way of checking if your speaker is blown is by measuring the resistance. You can do this with the help of a multimeter if you have the tool at home.
You will first need to disconnect the sub from the power source before unplugging the audio input from your subwoofer. If the sub isn’t powered by an external receiver or amp, then you’ll have to remove it from the enclosure.
From here, proceed to connect the probes to the multimeter then turn on the device to measure ohms. The red probe is inserted into the (+) lead whereas the black probe is inserted into the (-) probe.
On a normal speaker, the resistance reading is supposed to stay constant when you measure it on a multimeter.
So, if you notice that the reading keeps on shifting and fluctuating, this is proof that the speaker is blown.
What Causes a Speaker to Blow?
There is a range of issues that could be behind a blown speaker. For example, if you apply too much power to the voice coil, the speaker might blow. The same is true if a capacitor fails.
Generally, there are different reasons behind a blown speaker but the main one is electrical failure.
Once you’re sure that your speaker has blown, you should take it to a technician for the relevant subwoofer repair if you want to keep on enjoying good sound from it.
The next time you’re worried you might have blown your sub but you just can’t tell for sure, remember to check the above symptoms for a quick diagnosis!