Air space behind absorbing panels cheaply improves absorption performance

Evidence

All absorbers, wherever they are located, should be 3 to 4 inches (76 to 101 mm) thick if possible. Recall that as shown in Figure 12.20, a space behind an absorbing panel is an inexpensive way to improve performance. Filling the space with low-density fiberglass is beneficial. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1439

Categorization

• XREF: Connects to the standing ADDENDUM piece on trees as infrastructure only loosely; more directly a practical build tip worth pairing with absorber design notes in the reader’s audio setup knowledge.