Guys, my attention has been elsewhere the past couple of weeks.
The catalyst for the original post was to go beyond the usual "speakers in a room" approach, and use the room itself as an integral part of the sound. IB seemed like an attractive way to make this happen. The IB "rule of thumb", manifold exhaust area >= Total Sd, made me wonder about any potential benefits resulting from purposely undersizing the opening to load the drivers with mild compression.
My original idea was a baffle style IB, similar to the picture from ScottL. But many users report that wall manifolds require heroic bracing to mitigate flex. The manifold implementation side-steps around this problem by balancing the physical driver movements. The sole downside I see with a manifold is managing the exhaust area. This led to my idea that a purposely undersized exhaust could potentially result in more pleasing bass. My manifold placement uses the floor / wall boundary to support the bass output as well. Sound? Well this is one of those crazy audio projects that will be impossible to predict the outcome until after building.
My woodworker is visiting on Thu to discuss the build. I expect the manifold dimensions will be defined by building and implementation considerations, like spacing between the floor joists, and bracing. Will update further. |
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