ADHD is characterised by impaired inhibitory control of irrelevant stimuli. The irrelevant speech and ambient noise of an open-plan office (60–70 dB) constitutes a near-continuous demand on attentional resources that the ADHD brain has reduced capacity to filter automatically. A 35 dB reduction brings the ambient level inside the pod to approximately 30–35 dB — a level at which irrelevant speech from outside becomes inaudible and no longer competes for attentional resources, allowing directed attention to be sustained.