Plain

The core component of a Zorba model is an absorptive element such as glass wool or mineral wool which is assumed to face out to a rooms acoustic field while also being backed by a solid wall.

The acoustic absorption performance of the core element is calculated in Zorba as a function of thickness and flow resistivity.

Flow resitivity

For some materials the flow resistivity may be calculated from their density (see for instance Beranek's Noise and Vibration Control). This box allows one to calculate for some common materials. Generally speaking the flow resistance increases as something like the 1.5 power of the density and the inverse square of the fibre diameter.