Infinite baffle

Infinite-baffle mounting, is the easiest of all types of a woofer enclosures to install in your vehicle! 

Performance from this type of installation, is typically good, but may vary from vehicle to vehicle.

This design does not require designing or building an enclosure, so it saves time and money.

Custom Car Audio Boxes - Subwoofer Enclosures Infinite Baffle "Enclosure" When utilizing the Infinite baffle design, the woofers front cone is isolated from the rear cone when mounted on the "baffle board". The baffle board is the board that the woofer is mounted to. Advantages of this design include simplicity, minimal occupation of space. Disadvantages of this design are larger power requirement, difficulty (sometimes extreme) in completely isolating the two sides of the cone from each other, and slightly less accurate sound reproduction.

As with any speaker box design there are disadvantages and advantages of design type.  Unfortunately, there are several disadvantages to the infinite baffle. When a speaker is mounted in an enclosure, the air inside the enclosure acts like a spring against the speaker cone, and the resulting buildup in pressure provides mechanical damping and prevents excessive cone movement. But an infinite-baffle installation does not use an enclosure, so the mechanical damping is poor, resulting in "hang-over" and lack of definition. The power handling of the speaker will also be compromised since the infinite baffle provides very little control over cone excursion.

Building the box

When utilizing the infinite baffle design, the woofers front cone is isolated from the rear cone when mounted on the "baffle board". This basically uses the vehicle as a box. If you elect  to use this design, make sure you purchased the correct type woofers and, as each woofer has its own designed function.

as mentioned there are many types of woofer speakers on the market. They're many speakers available for infinite baffle or "free air" applications of available, usually the biggest difference from free air speakers and sealed box speakers is of the "stiffness" or spring action of the speaker cone. Speaker cone stiffness is simply, how easy it is to move the speaker cone back and forth. In a sealed box enclosure, woofer cone movement is controlled by the air tight seal. This seal will control speaker cone movement.