Creative Speculation

I would not be shocked if some things exploded spectacularly at or near ground level. You're talking about 2 100 acre buildings full of electronics, plus another large building, plus a power substation.

Have you ever seen what electrical transformers do when shorted out?

I would also not be surprised if mechanical forces, such as extremely heavy objects falling, hitting the ground were mistaken for explosions as well. Recall that the soft, wet bodies of humans hitting the ground after jumping from the towers are clearly audible on multiple ground-level videos from many blocks away. Drop a 150lb chunk of aluminium cladding 60 stories, what does it sound like when it hits the concrete street below?

Shit, we still have people who witness tornadoes trying to describe what sort of locomotive it sounded like. Humans associate information. We don't record it like a reel to reel.

Edit: and you are STILL dodging the question of how ground-level demo charges produce or even aid an impact point-down collapse of the buildings. Not the top. Not the bottom. Collapse starts where the fires were hottest, where the planes hit the two main towers. Please explain what sort of witchcraft produces a 'controlled demo' that behaves in that manner.