C. I. Holmer
Noise Control Technol., Inc., 2440 Freetown Dr., Reston, VA 22091
Professor L. Cremer was avidly interested in the transmission of sound through walls as part of his practice in architectural acoustics. The frequent use of masonry constructions for partitions and exterior facades in Europe, and their documented departure from ``mass law'' sound transmission performance led him to study this phenomenon in detail. He first identified what we now call the wave-coincidence effect (i.e., the matching of sound wavelengths in the surrounding fluid with the flexural wavelengths in the panel) as the mechanism which produced the non-mass-law performance in the 1940s. This work influenced London, Beranek, Watters, and Feshback in this country, leading to our present understanding of this phenomenon. His later work in impact sound transmission for masonry floors, and the transmission of flexural waves through wall junctions for flanking transmission also had a pioneering quality. Cremer systematically and significantly altered our understanding of sound propagation in buildings and other structures. This paper will review these several pioneering investigations to help us appreciate this giant of our field, on whose shoulders we all stand.