Have you tried restarting your ants?
ispy, the three main books agree that it was not possible to move around the house without making noise; that sound carried everywhere; and that detectives tested to see what sounds could be heard in the master bedroom from other locations in the house. Unfortunately, none of them specifically name JBR's bedroom as one of those locations, although common sense suggests that they would have tested shouts from there.
We all need to remember that the enclosed staircase on the west side of the house extended from just outside JBR's room to the west side of the master suite and would have conducted sound directly between the two. Interestingly, the sound path between JBR's room and BR's room is not direct at all - baffled, in fact, by the zigzag in the hallway that connects the area outside JBR's room to the play room (and from there to the hall leading to BR's room).
Just to complete the set ---
from Foreign Faction (Kindle, p. 134):
Detectives sometimes stayed into the wee hours of the night, listening to the creaks and groans of the old home. It seemed that one could not move about the house without being heard from another area of the home. Nearly every step taken seemed to cause some type of audible response from the floor joists of the structure.....
Detective Gosage had moved around to different parts of the home to see if shouting could be heard from the third-floor master suite of the parents. Investigators were trying to determine if the family would have been able to hear the same scream that neighbor Melody Stanton had claimed to hear. BPD investigators reported hearing Gosage’s shouts from various locations of the home, including the basement.