I will agree the collapse could have masked the sound...however, if you claim that demolition devices were used to initiate the collapse, then by definition, at least some of the devices would have had to been activated before the start of the collapse in order to cause the collapse. Anything that produces enough energy to either cut through or heat the columns or trusses to failure would create byproducts...light, sound, smoke, etc.
By the time the towers collapsed, there were hundreds of cameras pointed at them. There is a wealth of video and audio documents that clearly show the events that happened immediately before the collapse initiated. At no time during the last 30 seconds before the collapse do we see or hear anything that would indicate a high energy device going off. There are no flashes of light before the collapse...no extra sounds...no new sources of smoke of a different color...nothing. If a device caused the collapse, there would be evidence of some sort of it going off before the collapse started. We just don't see or hear it.