The effects of special coatings on the Sabine–Guastavino Rumford acoustical tiles.

Wallace C. Sabine and Rafael Guastavino developed the Rumford tiles specifically to lessen the reverberation times inside ecclesiastical edifices. These tiles are used in a number of churches, including St. Bartholomew and St. Thomas, both in New York City, and the Duke University Chapel in Durham, NC. In recent times, those responsible for musical programs have been demanding greater reverberation times, even at the expense of clarity of spoken words. Accordingly sealers are being applied to a number of church interiors in order to increase the reverberation times. Because of the limited samples available, the tone burst method was applied at the Cooper Union Acoustics Research Center to measure the effect of applying special coatings to decrease sound absorption coefficients. The absorption coefficients were measured for the naked tiles, provided by the First Congregational Church of Montclair, NJ, and after the consolidator was sprayed on. The test was also repeated for each application of the sealer. ...