Room as echo chamber

This bedroom was particularly noisy. Thin walls and creaky floorboards. It seemed you could hear everything that was being said in the neighbouring rooms. So was the room acting as a resonating chamber, a sound box. It was about 4 metres long. For a stationary wave with a node at each wall, that would mean a wavelength of 8 metres. Frequency = speed of sound/wavelength = 340/8 = 43 Hz. Even for a male voice, this would be a bit low. On the other hand, 100Hz might just hit the second harmonic!