What are the important issues in constructing a vented or PR enclosure?
A vented enclosure is normally larger than a sealed enclosure, therefore heavy bracing is needed. Without bracing, a vented box will sound boomy. Second, use double flared ports (that is, flared opening at both ends). They do make a difference in reducing any ‘chuffing’ noise that may result from port turbulence. Third, apply 1″ thick polyfill to the wall. Adding too much polyfill will increase the enclosure loss and therefore make the ports less effective. A passive radiator enclosure should ideally have two radiators on opposing sides of the box so that their forces act in symmetrically opposed directions. As a result, the net forces cancel. Care should be taken to ensure that the passive radiator will not be required to use too much of its maximum excursion, as the mechanical linearity of the suspension system will be less, resulting in higher distortion. Passive radiators are often used up to their excursion limits, and this is often not considered a problem since the distortion pe
