Above are shown the widths of the six-foot exponential loudspeaker horn at suitable short intervals along its length. The material necessary for making one of these horns can be obtained from a single sheet of wall board. The pattern, which is shown in Fig. 1, is prepared and laid upon the wall board; and the latter is cut along the lines indicated, allowing on one side an extra lap equal to the thickness.

Radio Record, Volume I, Issue 49, 29 June 1928, Page 2

Above are shown the widths of the six-foot exponential loudspeaker horn at suitable short intervals along its length. The material necessary for making one of these horns can be obtained from a single sheet of wall board. The pattern, which is shown in Fig. 1, is prepared and laid upon the wall board; and the latter is cut along the lines indicated, allowing on one side an extra lap equal to the thickness.