Infrasound Anomaly
The Hum of Bratislava
Bratislava, Slovakia — first reported 2005
~50 Hz (mains frequency)
Reported primarily in the Petrzalka housing district, a massive Soviet-era concrete housing block complex. The identical buildings may create acoustic resonance chambers.
Theories
- Structural resonance in uniform concrete panel buildings
- Danube River hydraulic infrasound
- Industrial district across the river
- Electrical grid harmonic resonance in dense housing