The most commonly used type of loudspeaker baffle is a closed box in one side of which the loudspeaker is mounted. In this type, discussed here in considerable detail, the back side of the loudspeaker is completely isolated from the front. A customary type of closed-box baffle is shown in Fig. 7.3
. The sides are made as rigid as possible using some material like 5-ply plywood or MDF, 0.75–1.0
in. thick, and braced to prevent resonance. A slow air leak must be provided in the box so that changes in atmospheric pressure do not displace the neutral position of the diaphragm.
When selecting a loudspeaker, the first two questions that arise are how loud must it go and what bass cutoff frequency can be tolerated? This ...