Device for listening to and recording of the sounds produced by birds or other distant objects. The device (FIG. 1) is attached to a pair of binoculars or a telescope and consists of one or more directional microphones, microphone structures or sets of microphones, a microphone and headphone amplifier...http://www.google.fr/patents/US5007091?utm_source=gb-gplus-shareBrevet US5007091 - Procedure and device for facilitating audiovisual observation of a distant object
Procedure and device for facilitating audiovisual observation of a distant ...
