Calculating box volume
There are several easy steps in determining the volume of an enclosure. By accurately calculating the amount of useable airspace available you can then maximize the performance of your application and achieve the desired results
Note: All measurements and most calculations will be performed in inches
First Step
The first step is measuring for physical dimensions in the vehicle. Prior to, or during this measurement, the shape of the enclosure will be planned. This measurement will enable you to obtain exterior dimensions of the enclosure
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The next step is converting these measurements into interior dimensions. This is done by determining the size of the material (particleboard, MDF, Plexiglas, etc.) that the enclosure will be constructed of. Generally, this thickness measures 3/4 inch. Now this thickness must be multiplied by two for each dimension (top-bottom, front-back, left side-right side). This figure is then subtracted from each exterior dimension of the enclosure. This calculation results in the interior dimensions. Having obtained these interior dimensions, the next step is calculating the volume.
| Important formulas: |
Volume of a rectangular box = Length x Width x Height Volume of a triangular box = Length x Width x Height x 0.5 Volume of a cylinder = 3.14 x Radius x Radius x Height Radius = Diameter x 0.5 |
Note: If the enclosure is not a rectangular box, calculating total interior volume will probably require a combination of the above shapes.
After internal volume has been calculated, it is then necessary to compensate for speaker basket and vent (port) displacement. When calculating, we multiply the speaker and vent displacement by the number of each being used. The volumes for speaker(s) and vent(s) are then subtracted from the internal volume of their respective chamber.
The last step is to convert inches into feet. This is achieved by dividing the volume in cubic inches by 1728 (one cubic foot = 1728 cubic inches). The result is the usable airspace for your enclosure is cubic feet.
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