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The difference between the recording and reconstructing wavelengths used in acoustical holography leads to a longitudinal distortion in the image. Furthermore, one of the important advantages of the three-dimensional nature of the hologram image, namely, the parallax effect, cannot be utilized unless resolution in the image is sacrificed by not using the full hologram aperture. This paper describes the experimental apparatus and a technique whereby the principles of multiplexing by holography are extended to 3-D representation of acoustically acquired data. It will be shown that full aperture sharing among the recorded wavefront of B-scans is compatible with off-hologram-plane sampling, so that the convenience of off-hologram-plane sampling can be combined with the image properties characteristic of the full aperture. Experimental results demonstrating the usefulness of the technique in ultrasonic diagnostics and nondestructive testing are presented. The possibility of using it in earth holography also will be discussed. [ABSTRACT FROM AUTHOR]