The ornamental design for decorative signal transducing necklace, as shown and described.
FIG. 1 is a front view of a decorative signal transducing necklace showing my new design, drawn broken away for indeterminate length.
The design is directed to the ornamentation applied to the headset. The earphones (depicted as EARBUD style headphones), the audio connector, the fastener (depicted as two touching hemispherical objects) and the microphone (depicted as a rectangular object) are shown in broken lines. The broken lines form no part of the claimed design.