| Re: So, what's with room gain?
Its actually two separate things. There is the boundary gain that you get from the operation in non-4Pi space. In non-technical jargon that means that the output of the driver is focused into a smaller space. Less space = more apparent output.
The other type of gain is the pressure-vessel gain. Below a certain frequency the room no longer supports standing waves. When the wavelength is greater than the room dimensions, you get a uniform pressurization of the room. You get more gain as frequency decreases so its called "room gain". This is more apparent in small tightly sealed environments. Cars are a great example and the pressure vessel gain you get inside that environment is substantial. Its occurs lower in frequency and to a lesser extent inside a room. Typical living spaces are not tightly sealed acoustic chambers and their construction varies, giving different results depending on the physical properties of the floor, wall, ceiling, etc… Boundaries that are sturdy and stiff (concrete) give more re-enforcement than does stick-built or flexible building materials that will absorb some of the energy. Think of the Three Little Pigs. ;-)
|