Next, you enter either an inside diameter for the tube you are using if you want a circular port, or the inside dimensions of the square port you are going to build into your box (make sure you click the 'Slot Port' button if you are designing a slot port - if you don't understand the difference between a square vent and a slot vent, click here. The port length should be 16 inches deep. This tunes the boxes to about 40 Hz. How To Make A Slot Port The easiest and most effective way to build a port is to use a slot shaped port that uses 3 sides of your enclosure as port walls. If the port is located at one end of the box, only one additional piece of wood is required to complete the port. H = height of slot port w = width of slot port d = diameter of equivalent round port so to compute the 'diameter' of the port as a function of the slot height and width i would use: (using the + obviously) This makes sense to me because given any port length L, the total volume of the port will be the same. The 'Minimum Port Area Required' result is how much port area you will need to keep port velocity under about 30 meter per second for slot ports and 32 meters per second for aero (or other round) ports. Port velocities above these numbers are where serious port compression sets in and you begin to lose a LOT of output. Remember, just like the round port, only use the length that extends into the enclosure when calculating the port’s displacement. Figure N shows the internal and external dimensions of the port. The external dimensions will be used when calculating displacement. Calculating the displacement of a slot port is very similar to calculating.

1. Round Port Calculator
2. Slot Port Design

Overview:

This is a calculator for designing a L-Slot Vent Bass Reflex Enclosure. The formulas used in the calculator create a design that suggests the most maximally flat response in an anechoic environment based on the number of drivers, the thiele small parameters and the allotted dimensions specified in the user’s input fields.

The calculator does NOT take into account the effects of placing the enclosure into the listening environment. This type of enclosure may not be the most suitable option for your application. I recommend reading the articles in the Projects category on box design for further information.

Feel free to check out the other calculators on the site as they may provide the results you are looking for. —> Enclosure Calculators You can also request a totally custom design for your driver(s)/application by filling out the form in the Blueprints Inquiry page.

The spreadsheet calculator loads via iframe below the diagrams. You can also access the spreadsheet here.

Instructions:

Round Port Calculator

Slot Port Design