Acoustic Sweep at the Perimeter

The relay line beneath the radiator was stable, so I relocated to the front entrance threshold. A heavy aluminum draft strip sealed the bottom of the exterior door. I approached the rubber weatherstripping where it compressed against the hardwood floor. Taking the pry tool, I tested the flex of the black rubber fin. High resistance, clean rebound. A steel screw head sat slightly recessed in the floor channel, dusted with dried street grit. I tapped the screw head once with the pry tool's heel. Crisp, non-resonant click. The external barrier is tight. No exterior draft penetrates the seal.