How To Make a Sealed Box Louder By Adding Plastic Ports

 

The two main popular car subwoofer enclosures in the car audio world are ported and sealed. Sealed is often an choice if saving space is an factor and also if you want to go for sound quality. Ported boxes on the other hand are generally louder and slam harder. Ported boxes are ideal for rap and hip hop with low end deep bass, sealed boxes are more rock music that gives you that upper punch. This is because sealed boxes have less delay and tend to have an flatter frequency response. If you have an sealed box with no air hole or known as an port or vent, then you can make an simple modification to add more bass. Sealed boxes in my opinion do sound good, but to make them loud, you need an really high powered rms amp and sub combination, at least an 1000 rms. With an ported enclosure, you don't need to run as much power to get the same type of performance out of your speaker. 

Porting an sealed subwoofer enclosure is possible. PVC pipe that is used for guttering is cheap and cheerful to make it possible to port your sealed subwoofer enclosure. An 3 inch or 4 inch opening in diameter is good for smooth air flow and to prevent unwanted port noise from your car audio system. To tune your aero port for your sealed enclosure, you will need to adjust the length of the port. The longer the port the lower the HZ frequency tuning will be, the shorter the port, the more louder the bass tuning will be. The best way to do this is to first workout how much cubic volume the sealed box that you want to port is. The can be done by entering the length, width and height measurements in an online subwoofer box calculator. 

Ported boxes are generally bigger than sealed. This is why you invert mount the subwoofer in the sealed box that you want to port. So the magnet sticking out of the box instead of the cone. The subwoofer magnet and metal basket takes up room inside the box. By inverting your car subwoofer, you are reducing the amount of cubic feet volume that gets taken up. This makes the sealed box bigger inside. 

Once you have the cubic volume of your sealed box, use an online port calculator, enter the values of the cubic ft volume of your box, the diameter of the port opening and the length. This will then display an HZ value, lower deep bass you want to tune the port to around 33 HZ, for louder SPL boomy sort of bass you want to port to achieve 40 to 50 HZ tuning. Play around with the port length in the calculator to get the desired tuning frequency you want to achieve. Then get an saw and cut the port plastic to your length and use sandpaper to file down the rough edges to smooth it out. Adding the port to your sealed subwoofer enclosure is easy, simply mark up the diameter, by placing the port on top of the box and mark it with an pencil. Once you have made the cut out outline, get an jigsaw and cut it out. Push the port in and seal the inside around the port with silicon, this will prevent air leaks.You might want to vacuum inside the subwoofer box as there will be dust inside from cutting the MDF.

Thats it! Your cheap sealed prefab box is now ported, enjoy the extra boom without spending money on an expensive custom enclosure.

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