Time lapse of the WTC collapse. The footage has been sped up by 400% making the LF signals more audible on low quality monitoring systems (i.e Laptop speakers). Many claim the thuds and bangs are wind on the microphone(!). As an audio engineer of 10+ years of experience I can confirm this certainly is not wind you are hearing. The bedrock of the Hudson and the clear space in between the water and the buildings allowed for the capture of this unique audio. Unlike many microphones close to the building that were flat lined by the sheer volume of noise generated by rescue workers, sirens, vehicles, screams and other factors like deflection from large surrounding structures, the audio capture from across the water was unhindered by such factors and a clear recording of the lowest frequencies were captured. Low frequency signals travel much farther than high frequencies, they also take more power to produce. Overloaded camera microphones near the trade center simply wouldn't be expected to pick up such signals. This audio track for me is a smoking gun of something fishy happening to the towers and should be considered by any serious researcher as to what was taking place inside the buildings. (less info)