How to Measure a Subwoofer?
Subwoofers can take your music experience to the next level if they work fine. But when a subwoofer starts showing malfunctioning signs, you have to replace it with a new one. However, replacing your old subwoofer with a new subwoofer is easy. But when you want to use the old enclosure, you must ensure that the new subwoofer fits in the box.
Most probably, you can know the subwoofer’s size by looking at its back sticker. However, it can be tricky for you if there is no size mentioned on the subwoofer and you don’t know how to measure a subwoofer size. As an audio expert, I will share with you the most effective methods so that you can easily replace your old subwoofer with a new one without wasting your money on the wrong-sized subwoofer.
You can use a ruler or measuring tape to determine the readings of the subwoofer’s mounting height, cutout depth, and mounting depth. These readings will help you get the exact subwoofer’s size.
What Data Should You Measure?
As mentioned above, you have to get the readings of the subwoofer’s mounting depth, mounting height, external (speaker) diameter, and cutout depth to get the overall physical size.
1. Mounting Depth:
It is the measurement of the distance from the bottom of the mounting surface to the back of the speaker cone. Or You can also say it measures the distance from the front of the speaker cone to the rear of the subwoofer, including any protruding parts such as the terminals or voice coil. It is critical when selecting a subwoofer as it determines how deep of an enclosure you need for installation and proper performance. The deeper the mounting depth ⁽¹⁾, the larger enclosure required for proper operation.
2. Mounting Height:
Mounting height measurement depends on the type of subwoofer you have. It is usually measured from the lowest point of the mounting plane to the top, outermost edge of the subwoofer’s front panel. You should take the reading in a straight line, not including any curved edges. Also, consider it an essential measurement as it determines how far the subwoofer projects from the front of the mounting surface.
3. Cutout Diameter:
It is the distance between opposite faces of the mounting hole for the subwoofer, usually measured in inches or millimeters. Cutout diameter measurements are essential because they affect how well a sub will fit into an enclosure and ultimately determine its performance. Additionally, measuring the cutout diameter accurately can prevent potential damage to the subwoofer due to improper fitting.
4. Speaker or External Diameter:
You can measure the speaker diameter (AKA External Diameter) by measuring the subwoofer’s speaker cone from one end to the other (left to right), excluding any mounting lugs. This will help you choose the right subwoofer size for your older enclosure.
How to Measure a Subwoofer?
1. Take Your Older Subwoofer Out From the Older Enclosure:
Start by disconnecting the power and unplugging any cables connected to the amplifier. Next, locate the screws or bolts that attach the subwoofer to the enclosure and unscrew them through a screwdriver until they are free. After removing all the screws, carefully remove the subwoofer from the older box by gently pulling it toward yourself.
Also, if there are any wires attached to the subwoofer, disconnect them so that you won’t break them. After removing the driver, place it on a flat surface to start measuring the subwoofer.
2. Measure the Mounting Depth:
Before you begin the step, place your subwoofer in the upright sitting position, as it will help you collect the data accurately. You can use a ruler if the subwoofer is smaller than it. However, if your ruler is smaller than the sub, you can use a measuring tap.
Now, you will need to measure from the front edge of the mounting surface to the back of the speaker cone or voice coil. Start by placing your measuring tape at the base of the mounting surface and extend it until it reaches the back of the subwoofer’s cone or voice coil. Make sure to account for any protruding parts, such as the terminal or voice coil, that might be sticking out from the back of the subwoofer. The mounting surface can be a metallic or plastic plate around the cone. This is how to measure the subwoofer’s mounting depth.
3. Measure the Mounting Height:
With the drive upright standing position, start by measuring from the bottom side of the plane to the top edge of the subwoofer’s front panel (highest point of the projection). Make sure that you take a straight line without any bends or curves.
You need to place the subwoofer in such a way that the cone faces the upward direction. You can use a measuring tape or ruler and start the process by measuring the bottom of the sub up to the mounting frame. A mounting frame is a piece of metal or plastic wrapped around the cone. Remember that you could damage the sub if the height extends too far. This is how you measure subwoofer mounting depth.
4. Measure the Cutout Diameter:
Measuring the cutout diameter of a subwoofer is straightforward. All you need to do is take out a ruler or measuring tape, place it in the opening of the one mounting hole, and measure the distance between opposites sides. Ensure you measure accurately to ensure a proper fit when installing your subwoofer. After taking the measurements, convert them to either inches or millimeters.
Method to Measure the Mounting Holes:
Now that you have measured the subwoofer’s dimensions, let’s move forward to measure the mounting holes of the older subwoofer so that you can get the new subwoofer and compare the holes with them. Or you can drill the holes on the new subwoofer if necessary. Follow these steps:
1. Gather Your Tools:
Before you start measuring, ensure you have the essential tools to note down the readings, such as a measuring tape or ruler and a pen or pencil.
2. Trace the Mounting Holes:
After you gather the required tools, the next step is to locate the mounting holes. You can easily find them by looking at the back of the subwoofer and finding the mounting points where screws or brackets would attach it to an enclosure. You should locate these mounting points on either side of the subwoofer, just above where the speaker connects to the back of the box.
3. Measure the Distance Between the Holes:
Once you have identified the mounting holes, begin by placing a measuring tape or ruler between the centers of the two holes. Make sure that you have aligned the tape correctly and that it is not pulled in any direction so it can give an accurate measurement. Note down the measurement you receive, as this will be necessary when installing your new subwoofer.
4. Repeat the Process Until You Measure All the Holes:
If your old subwoofer has more than two holes on the mounting frame (circular metal frame), repeat the process to measure the distance between the centers of all the screw holes. This is essential as each enclosure hole may have a slightly different length, and you must consider this during installation. Once you have measured every mounting hole, compare your measurements to ensure they are consistent before proceeding with the installation.
General FAQs
What Is a Subwoofer Diameter?
A subwoofer diameter is the measurement of the physical size of a subwoofer’s speaker cone. It typically measures in inches and can range from 6 to 18 inches, depending on the specific subwoofer. Smaller sizes are used for home theaters or desktop audio systems, while larger sizes are designed for more powerful bass tones in the car audio setups.
How Do You Measure the Subwoofer Box Cubic Feet?
To determine the cubic feet, measure the box’s height, width, and depth in inches, then multiply those three numbers together to get the total volume in cubic inches. Divide that number by 1,728 (the number of cubic inches in a cubic foot) to get your result in cubic feet. E.g., if your box measures 24 x 16 x 12” = 4608/1728 = 2.67 cu ft. That’s it! Now you know how to measure your subwoofer box to obtain accurate results for its size and shape measurements.
What Size Sub Is Best for Bass?
It depends on the size of your room and the power of your amplifier. Generally, bigger subwoofers produce more bass in larger rooms, and a powerful amp is needed to drive them. An 8-inch subwoofer is sufficient for making good low-end bass for most setups. However, if you are looking for deeper and richer bass tones in larger rooms, then 12 or 15-inch subs with at least 250 watts of RMS power may be necessary. The best way to decide which size subwoofer works best for you is to experiment with different sizes in different-sized rooms.