A door assembly and a door closer arranged and constructed so as to be wholly concealed within the associated door, yet is rendered readily accessible to effect the adjustment thereof to regulate or control the closing speed of the associated door. In one embodiment, a plurality of controllable inputs to an integrated circuit is adjusted to achieve a frequency specific predetermined value of a dynamic operating indicator of the integrated circuit at the desired specific operating frequency. The base has an outer longitudinal surface, a first end portion having a first edge surface, a second end portion having a second edge surface, and at least one set of apertures. A force generating apparatus is also mounted to the frame, the force generating apparatus configured for pulling the first pipe relative to the second pipe.