How to Test a Subwoofer?

6 Things to Check:

Here is the list of five things you need to check to ensure your amplifier power subwoofer is working fine:

• Sound
• Cone
• Coil
• Blown-Subwoofer
• Age
• Model

1. Sound:

Sound testing for your subwoofer is essential for several reasons. It will help you to understand how your sub is performing. Once you measure its frequency response & room eq, you can quite ensure that the low-frequency sounds are still working smoothly.

Moreover, testing your subwoofer’s sound can also save you money in the long run. If you figure out the issues early before they damage the subwoofer more severely, you can quickly fix them out. Otherwise, you’ll more probably like to replace the components.

Also, by regularly testing the frequencies (every month), you can easily spot the faulty parts, allowing you to upgrade the sound system even better without experiencing bad sound quality.

You can quickly test it by identifying the right frequency range for your particular setup. Then, using a test tone generator ⁽¹⁾ or oscilloscope ⁽²⁾, you can measure the frequency response. These tools will help you identify the problems more efficiently rather than manually. Additionally, if the distorted sound is present, you can also identify and fix it with the help of a distortion analyzer.

Note: If your room or car acoustics are impacting the sound quality, using an EQ setting will help to optimize performance by reducing any standing waves or reflections that may occur in the space.

2. Cone:

You also need to ensure that your subwoofer’s cone is in good shape, as it can be a tell-tale sign as to whether or not your audio system is functioning correctly. Simply, a malfunctioning cone could lead to distorted noise, low audio quality, and even no noise.

You can quickly check the speaker’s cone in a few setups:

1. The first step is to check it for any signs of damage or defect. You can visually inspect it and feel around the edges with your fingers for bumps, cracks, or other irregularities in no time. If you find any damage, it’s best to replace it immediately ⁽³⁾, so you’ll get back your quality sound.
2. Now, let’s see if your cone movement is working usual or causing any stuck. You can do this by turning up your audio system and then gently pushing down on top of it with your finger. If it moves freely, there are no blockages, and it returns to its original position without resistance, then it functions correctly. If it does not move freely or you find any stuck in the cone’s movement, it could be an issue, and you should consider replacing it.

3. Voice Coil:

You may look at and consider the subwoofer’s coil as a standard component. But believe me, this tiny thing is essential and entirely responsible for creating bass tones. So it basically controls the overall sound quality of your system.

You must ensure that the subwoofer’s voice is in the best position and shape to maintain sound quality. Otherwise, if you find any problems with it, consider replacing it with a fine one by a professional expert. Also, you should keep checking the coil regularly to detect the issue at the initial stage to avoid any severe damage.

Testing the performance of the voice coil also allows you to identify potential problems, such as blown-out speakers or poor frequency response. To test the performance of your subwoofer’s voice coil, you’ll need to follow the below steps:

• Disconnect the electrical source of the sub. Remove the subwoofer from its enclosure carefully without cutting or damaging any wire.
• Now check the resistance of the subwoofer’s voice coil with a digital multimeter. Make sure that it reads within acceptable levels for your particular model. If everything looks OK, you need to move to the next step.
• Now look for any visible wear and tear, such as cracks in the voice coil or frayed wires. If you don’t notice anything unusual, then it’s working fine.

4. Check if Your Subwoofer Is Blown:

A blown subwoofer has the capability to damage your stereo system even more if you don’t detect it on time. One of the first signs of a blown subwoofer is a decrease in overall audio quality. Also, you will notice some unusual sounds from your subwoofer after you play any music on a high level.

Other signs of a blown speaker include unusual rattling sounds or vibrations from the speaker. Sometimes, you may also smell burning, which indicates a short circuit that can cause permanent damage to your system. You must confirm your diagnosis with a visual inspection if you’ve identified any of these signs in your audio system. To do this, you’ll need to remove the subwoofer’s protective grille and look at the speaker cone.

If You’re Buying a Used Subwoofer:

Additionally, you will need to consider the following things before getting a used subwoofer:

5. Age:

Age is also essential to determine if you’re going to buy a used subwoofer or use one. Subwoofers can start to degrade or experience difficulty functioning over time due to their components wearing down or becoming brittle. Also, you can easily spot how well the previous owner has cared for the subwoofer by determining its age. If the subwoofer has little age but the condition is rough, you can easily figure out it’s been roughly handled.

By checking your subwoofer’s age, you can better understand its condition and longevity before making a purchase. Additionally, if you’re looking to repair or replace components within your subwoofer, knowing its age can help you find the right parts and ensure they are compatible.

6. Model:

When you test a subwoofer, you must also ensure it’s a good model from a reputable brand. You can quickly check its model by looking at the unit’s labeling on the back or underside. You will find information such as the manufacturer’s name and model number there. 

Also, this label is usually accompanied by other information such as output power, frequency response range, and impedance rating. Moreover, look for the information on that model online, whether it is good or bad, and check how other users have experienced it.

How to Test Subwoofer With a Multimeter?

You can also test the subwoofer using a multimeter by following the steps:

• Start by connecting the positive and negative terminals of your multimeter to the positive and negative terminals of your sub, respectively, using clips or other connectors.
• Now, please turn on your multimeter’s switch and ensure it is set to measure DC volt. Ensure that your subwoofer’s volume control is set to its highest level.
• Next, please turn on the power source of your subwoofer and start playing some music through it. You should notice the increase in the voltage in your multimeter’s display as you increase the volume of the music being played through the subwoofer. This indicates the subwoofer is functioning correctly.
• If the voltage does not increase as you increase the volume, this may mean that your subwoofer is malfunctioning and needs to be serviced or replaced.

How to Test a Subwoofer Without Multimeter?

You can also test a subwoofer without a multimeter by following below steps:

• Connect the woofer to an amp and an electrical source. Turn on the amplifier and set the volume to a low or medium level. Now, play the music of your choice through the system and slowly increase the volume until you can listen to the noise from the subwoofer.
• If there is no noise, check all the connections and ensure they are secure. Once you listen to the woofer, slowly increase the volume until it reaches its maximum level.
• Listen for any distortion or buzzing sounds coming from the subwoofer, as this may indicate a problem with the woofer itself or the amp. If any unusual or loud noises coming from the subwoofer, the subwoofer is malfunctioning. If everything sounds normal, then your subwoofer is in good working order.

Test a Subwoofer Using a 9-V Battery (Without an Amp):

You can also test your subwoofer without a multimeter or without connecting it to the amplifier by following:

• Connect the subwoofer to a 9v battery.
• Place your hand near the cone to feel if it’s vibrating and producing noise, or use an electrical tester for more accuracy. If you do not feel or hear anything, ensure the connections are secure and the battery is charged.
• If you hear noise from the subwoofer, adjust the volume control (If the sub has volume control options on its back) to increase or decrease the output level.
• To confirm if the audio is coming out correctly, use a frequency response tester to measure the bass output, mid-range, and treble levels.