OCR Text |
Show Simple Loud Speaker Has Proven Efficient The device here described has proven its efficiency in many rigid tests. It Is neat, simple, efficient, and It may be made at practically no cost. The materials are as follows: One block of soft wood 2V4 by 2 by 1 Inches. Two common tncks. One rubber band. The method of construction Is seen clearly by the drawing. The hole 1q the block Is drilled slightly larger than "Wiro'Vtfr! Horn h ut Aubber bond the horn end If It tapers. If the horn end Is not of conical shape, such as a phonograph tone arm, the hole Is made Just large enough to Dt snugly. The receiver Is placed as Is shown In lha cut. And It works I Try to beat that for simplicity, r Science and Invention sod Radio News.) |