Many signal processing techniques for sound source separation using microphone array have been studied as a robust audio recording method to ambient noise. However, the implementation in real-time is still hard to be realized in terms of its large computational cost. As an another approach, a directional microphone has a capability to record sound from a specific direction; however, it is impossible to pick up sound at a specific distance. As a part of research on acoustic transducer, on the other hand, a method to broaden the directivity by using the slant-plate acoustical lenses at the front of loudspeaker has been utilized. In addition, there is a report that a slant-plate acoustical lens combined with a conical horn shows a sharper directivity than that by a parabolic microphone. The authors have studied selective distant recording using acoustic lens that synchronously adds the wave fronts after removing the time difference of arrival via the speaking tubes having different lengths. As a result of that the shape of the speaking tube in the acoustic lens was replaced with exponential horn, an improvement in terms of sound quality with a reduction of resonance was obtained.