Acoustical treatment historically meant absorption, favoring dead rooms

Evidence

Commercial acoustical absorption has been around since the 1930s, when dozens of companies were manufacturing versions of resistive absorbers. The design of bass traps came later and fit the general pattern of acoustical treatment being synonymous with acoustical absorption. “Dead” acoustics became fashionable. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1660

Categorization

• XREF: Connects to the reader’s historical interest — commercial absorption since the 1930s and the ‘dead acoustics’ fashion.
• corroborated: 2 independent passages support this claim — Toole, Floyd E, Sound reproduction- the acoustics and…, 1660