How to Test a Used Subwoofer Before Buying?

Yup! There are no doubts you can buy used subwoofers at reasonable prices. Just before making a purchase, you must ensure you’re paying for a quality component.

Otherwise, you may get your investment burnt without having the pleasure of low-frequency bass sounds. So, if you don’t know how to test a used subwoofer before buying, the answer is simple:

You can follow many methods, such as physical inspection, multimeter test, sound test, or test after connecting the sub with a 12-volt batter, to ensure you’re paying for a quality subwoofer.

Read the article till the end for a complete tutorial!

4 Methods to Test a Used Subwoofer Before Buying:

These are the legit methods I use to test my clients’ used subwoofers:

1. Testing a Used Subwoofer Through Physical Condition:

The first method you can take is to look at the car subwoofer’s physical appearance. Follow the below steps:

1. Inspect the Subwoofer’s Exterior: When inspecting a used subwoofer, looking for any visible signs of damage, such as dents, scratches, and cracks, is essential. It is also necessary to check the edges and corners of the subwoofer for any signs of impact or mishandling.
2. Check the Speaker Cone: A cone is the central part of a subwoofer. So, when you look at the subwoofer cone, ensure there are no tears or punctures. Such damages can distort the sound quality, and you should avoid getting damaged cone subwoofer.
3. Check the Subwoofer’s Voice Coil: The voice coil is also integral to product bass sounds. It consists of a wire wound around an aluminum former to create an electromagnet. When inspecting, look for any warping or separation from the cone or magnet, which may indicate an issue with sound.
4. Check the Subwoofer’s Spider: It’s a flexible component that holds the voice coil in place with the magnet. You should check the spider for signs of fraying, tears, or other damage. If any such symptoms are present, then it is likely that the subwoofer will not function properly and may need to be replaced or repaired before use.
5. Look for Signs of Overheating: The signs, such as discoloration or warping of the magnet and voice, should be on the to-do list while testing a used subwoofer. The subwoofer blows because of overheating, which may reduce its sound quality or lead to total failure.

2. Testing a Used Sub Through Multimeter (Recommended):

If your subwoofer seems perfect after inspecting it visually, you must check it through a multimeter. Follow the below steps:

1. Remove the Used Subwoofer: Disconnect the subwoofer and remove it from its enclosure. This way, you can explore the subwoofer’s terminals closely. You can remove the subwoofer with a screwdriver.
2. Set Your Multimeter: Ensure you set the multimeter’s reading in Ohms. This voice coil resistance is the recommended reading (represents voice coil) to test a used subwoofer.
3. Connect Multimeter With Sub: Now connect the multimeter’s positive lead with the subwoofer’s positive terminal and the negative lead of the multimeter’s negative terminal.
4. Compare the Readings: Once you get the value, compare it to a specific subwoofer range (Check the user’s manual guide). A blown subwoofer shows a number other than mentioned and recommended range.

3. Testing a Used Subwoofer Through 9V Battery:

It’s not a recommended method from my side. But still, if you want to test the used subwoofer, you can use a 9-volt battery.

1. Remove the Subwoofer: Remove the subwoofer from its mounting position, and place it on a testing desk with a 9V battery next to it.
2. Make the Connection: Connect the negative terminal of the 9V battery with the negative terminal of the subwoofer and the positive terminal of the 9V battery with the subwoofer’s positive terminal through a strong wire (Present on the voice coil).
3. Observer the Cone Movement: If the subwoofer’s speaker cone moves in and out freely, it indicates the subwoofer’s voice is intact and not shorted.
4. Look for Distorted Sound: If the used subwoofer produces a distorted sound while moving, it shows subwoofer is blown. And you should avoid getting it.

4. Testing a Used Subwoofer Through Receiver:

Testing the used sub through a receiver is the most effective way to check its ability to produce sound. But make sure you don’t connect a powerful subwoofer with a weak receiver, as it may damage the amp or subwoofer itself. Always match the impedance; the audio input cables should connect to the power source.

1. Connect the Subwoofer: Take an RCA or speaker cable and connect the used subwoofer to the receiver. (Make sure you follow the connection requirements)
2. Use the Subwoofer’s Own Crossover: If the used subwoofer has its own crossover settings on the back, use this feature to test the subwoofer.
3. Use External Crossover: If your subwoofer doesn’t have crossover settings, get an external device and connect it to your audio setup.
4. Set the Crossover: According to the subwoofer’s manual or specification, adjust the crossover settings on the external device. Or you can also set the HPF and LPF on the head unit.
5. Play the Music: Now play the test tune or music and look for any rattling or buzzing sound. If you hear any unusual sound, it indicates the subwoofer is blown and should be avoided purchasing.
6. Use Different Settings: The subwoofer works well in the recommended crossover settings. Therefore, you must adjust the crossover on different levels to check the subwoofer’s performance.

5 Reasons to Test a Used Subwoofer Before Purchasing:

The reasons that always make me test any used subwoofer before purchasing are below:

1. Testing Ensures Functionality:

It will help you assess the quality and performance. It can also help you identify any issues or defects that may not be immediately visible.

Making sure a subwoofer works appropriately is important because it can drastically affect the overall sound of your system, and buying one that doesn’t work correctly could result in wasted money.

Therefore, I always ensure its functionality before purchasing for more accurate price comparisons when shopping around for the best deal.

2. Detect Issues:

As mentioned above, testing the used subwoofer helps you find the defects. For example, a blown coil or other internal components could compromise the audio quality and durability of the subwoofer.

So, testing the subwoofer is essential to identify potential problems and minimize your risk of buying a blown subwoofer.

Furthermore, testing can also reveal how well-maintained the product is, which will give you an idea of its expected performance lifespan.

3. Verify Compatibility:

What If you buy a well-working used subwoofer, but your current audio system doesn’t support it properly? Therefore, you must also verify its compatibility before purchasing your existing sound system.

Otherwise, you’ll need to get an external amplifier for the used subwoofer. Compatibility testing also helps avoid impedance mismatches between the subwoofer and an amplifier and can help you identify the optimal placement within your space.

4. Negotiate Pricing:

That’s my most favorite reason to test a used subwoofer. Believe me, it helped me get an excellent deal I could never have imagined.

So, trying a used subwoofer before purchasing can help negotiate the price by allowing you to detect any issues or defects that might affect the item’s value. If anything is found, it will enable you to negotiate for a lower price. 

5. Peace of Mind:

Ultimately, it can give you peace of mind knowing that your money is not wasted on an item with poor performance or defective parts.

By testing the subwoofer, you can make an informed decision based on its sound quality and other features such as weight, power handling, and size.

Testing also allows you to judge if the subwoofer will fit in your room’s acoustic dimensions, which further aids in making a sound decision.

Things to Consider Before Testing a Used Subwoofer:

Please follow the below points before you test a used subwoofer:

• Check Subwoofer’s Specification: You must learn about its specifications before testing. This way, you know what to expect regarding power handling, frequency response, and other performance metrics. You can check the manual user guide. If not available, go to the model’s website.
• Having the Right Equipment: You must ensure that you have the right equipment, such as speaker wire, multimeter, amp, and receiver, to test the used subwoofer.
• Pick the Right Environment to Test: You must test the used subwoofer in a room without noise. This way, you can detect the rattling or buzzing sound from the subwoofer.
• Know the Seller’s Reputation: To avoid scams, you must ensure you’re dealing with a legit person. Research the seller’s reputation and read reviews from previous customers if you’re dealing with an online seller.
• Have a Plan for Negotiation: You must make a plan to negotiate the price with the seller if you find any defects in the used subwoofer before buying.

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