With regard to explosions, everyone seems to have their own anecdotal story about what they have heard.
Many here believe, and I do mean believe, rather than actually know, that explosions inside WTC1, WTC2 and WTC7 should have been quite audible.
Because of their real life experiences and/or because they have heard the recorded explosions shown in building demolition videos, it is a strongly held belief that eyewitnesses as well as recording devices should have easily heard any explosions.
To consider this issue fairly, you have to set your biases aside and consider the 9/11 World Trade Center events objectively.
Is it reasonable to dismiss eyewitness testimony and recordings that substantiate the existence of pre-collapse explosions?
It has been argued that because explosions from commercial controlled demolitions can be easily recorded, the same should hold true for the explosions at the World Trade Center on 9/11.
One of the best and clearest examples is this one, to which the firefighter on the phone reacts immediately. Other explosions are also highlighted in this video.
https://www.youtube.com/watch?v=_A9X_8flGeM
If you listen closely and crank up the volume, you can hear a muffled explosion (around the 11 second mark), in this WTC7 video just prior to its global collapse;
https://www.youtube.com/watch?v=XrnmbUDeHus
A big reason for why there are so few comparable recordings is sound proofing.
As I have mentioned previously, a building prepped for a commercial controlled demolition is emptied and its windows are removed. The sound from core explosives easily reflects off the hard surfaces of exposed floors and walls and easily radiates through open perimeter window frames.
Other than localized broken windows, the same conditions did not exist at the World Trade Center towers.
Regardless of whether or not partitions and floor furnishings stand from floor to ceiling, they are highly sound deadening. It may be claimed that these office environments are noisy but without those sound absorbing partitions it would be a loud cacophony. Additionally, the surrounding sealed perimeter windows (securely designed and installed to withstand the forces of nature), totally deflect all but the loudest sounds from inside and out.
It also must be considered that a commercial CD has nothing to hide, and therefore demolition engineers can focus on removing the core immediately to initiate a total building implosion.
Obviously in the case of a covert demolition masquerading as a collapse from plane impact and subsequent fire, a dramatic display of pre-collapse explosions would have been difficult to dismiss.
This would explain the presence of nano-thermite. As observed at the WTC2, once the corner column was cut and the upper section began to topple, pre-planted cutter charges could be ignited in a timed sequence. The sound of explosions, if evidenced (as they were by some eyewitnesses), could now be dismissed as the sound of the collapsing building.
In the case of WTC1 and WTC2, I would therefore suggest that until each began to topple above the impact zones, there would have been a minimal use of explosives.
Again, I point out that the three towers were huge and the energy release from their high speed collapses must have generated an enormous amount of sound.
At some time or another, we've all heard the loud explosive-like boom of a lightning's atmospheric thunderclap.
Yet, with the World Trade Center towers, while the eyewitnesses and public saw and heard something far more intense, the audio recordings largely failed to do it justice.
