In the presentation last year by Shyam Sunder it was said that they concluded that WTC 7 was not brought down by controlled demolition. They did not tests for explosives in the rubble or dust, instead they go on lenghts to prove there was no explosion sound measured and therefore it could not be a controlled demolition.
The engineer and explosive expert Ron Craig showed similar views in a Gage-radio debate.
Now this premise is clearly false, as the sound or blast waves were matter of new patents to reduce their effects.
So, if you ever be confronted with the “sound” premise, just show them theses patents:
US patent 6183669
"primary disadvantage of explosive shaped charges is that they generate excessive noise and debris upon detonation. This noise and debris can pose potentially serious health and safety hazards to someone using a cutting device which employs conventional shaped charge explosives.