There's dozens of recordings pertaining to Flight 175 slamming into Tower 2 of the WTC. I've chosen to whittle these down to a handful that are particularly gripping. 

In this tape, professional photographer/editor, Steve Vigilante, really brings out the noise and sound of the impact - even though the initial collision is not shown in the field of view. That smack is just so crisp, clear and loud. It truly must have been painful to hear...