The present invention provides an apparatus having a microphone, an analog to digital converting circuit, a semiconductor memory, input device, and a controller. A first row of die pads consists of a first group of four die pads and run in a first direction. The gas is permitted to migrate through the particulate material, but it is then vented to the surrounding atomosphere without causing substantial turbulence in the particulate material and to reduce tendencies for dusting and separation of the particulates into sizes. A downhole tool, such as a bridge plug, frac-plug, or packer, is also provided.