New Lord Manufacturing Company Acoustical Facility Free

A facility for measurement of transmission loss and sound‐power radiation has recently been completed at Lord Manufacturing Company. The facility includes a source room of irregular shape (∼2100 ft³ volume), and a rectangular main reverberant room of ∼11 000 ft³ volume, both of 12‐in. concrete‐filled, concrete block construction. A unique feature is a modular steel panel filler wall for providing flexibility in varying TL sample size from 6×8‐ft samples to 3×3‐ft samples. Data are shown that indicate the facility is capable of reverberant‐field TL testing with $110‐oct$ resolution from 125 to about 10 000 Hz with samples up to about 16 lb/ft² mass law. Beranek's criterion of 20 modes/band is satisfied in the main room to 63 Hz for 1‐oct analysis, 80 Hz for $13‐oct$ analysis, and 125 Hz for $110‐oct$ analysis.