Recently some friends and I had the opportunity to carry out some sound tests. Whilst not replicating all of the conditions of that night the results are nevertheless very interesting.
We had access to two villas which were of block and concrete construction. The area was on flat open ground but the villas were slightly closer packed than where OP lived.
Firstly I tried screaming as loudly as I could to see if it could be heard at a distance. At 80m in the open (paced out) 4 people in line of sight not expecting to hear anything did not hear anything unusual. This was at about 28 degC with a light wind blowing towards the witnesses. This was surprising to me as Burger and Johnson both reported "helps" at more than twice this distance.
Secondly we tested female screams at a similar distance. At 80m the screams could be heard clearly. At 177m they could only be heard as very faint by one witness . There was again a light breeze from the screamer towards the witnesses.
This was very surprising given what Burger reported but of course this was with surrounding buildings which could have redirected and "concentrated" the sound. It was not possible to replicate these conditions but it was possible to investigate how screaming from a room affected what was heard.
Next a woman screamed as loudly as she could from within a closed room inside the ground floor. The room had two windows like OPs bathroom but they were slightly smaller and double glazed. This screaming could not be heard any further away than 50m. In fact a woman and girl both screamed together. I expected that this would change when the window was opened. On opening the window completely the scream could be heard clearly at 50m and at 80m but became very difficult to hear at 100m and beyond.
Here is the most fascinating part.
From a villa next door no more than 10m away the screaming could not be heard at all even with the window wide open until the screamer was right next to the window and the witness was right next to an open window when it was clear.
Obviously those screaming were not doing so "for their lives" but I was stunned as to how the screams could be lost over such relatively short distances.
When you actually measure out 177m (580ft) it is a huge distance and seemed much further than I had been thinking of when first analysing the PT witnesses evidence.
I suspect the pattern of what was heard is to do with the tiled bathroom and pitch of the screams. It seems that high pitched sounds carry further. It's a shame you didn't try breaking down a door right next to the window to see who could hear that
