SONOMETER, THREE WIRE PATTERN, GEARED

A hollow wooden sounding box, about 1160x 120x 115mm (length x width x height) provided with 0-100cm scale at its top, with two wires stretched over fixed bridges, one at each end of the box. One wire passes over a horizontally mounted pulley and has a spring balance for directly reading the tension applied. The second wire is fixed at one end and attached to wrest pin for tension control and provides complete length of vibration. The third wire passes over a vertically pulley and for suspending masses through it for tensioning the wire. The wires supplied are of steel and are carefully selected to possess the exact determined density and radius uniformly throughout the length to avoid the need of repeated measurements. The wire tension mechanism is based on robust and mechanically sound thumb screw & gear system, which is accurate, more reliable and makes changing wires quick and easy. Complete with three moveable bridges, wrest-pin key and a set of four wires, length 1 m, diameters 0.70, 0.40 and 0.40mm. Supplied without masses.