Three-Dimensional Soundfield Standard
Dear Gary: Your forum call in September’s Widescreen Review for a “three-dimensional soundfield standard” has been addressed within the family of Ambiophonics, championed by Ralph Glasgal, termed Periphonic Ambiophonics. “PerAmbio 3D/2D (Patent pending) projects height sounds onto the horizontal plane of 5.1 loudspeakers for decoderless replay from any six-channel media, e.g. DVD-Audio, SA-CD, or DTS-ES Discrete. When ready to add a decoder and four or five loudspeakers, the home theatre owner is able to extract lossless 3D from the same disc. By “3-D,” I mean the listener is in the sweet spot at the center of, not just the circle of ITU 5.1/6.1, but the sphere of human hearing where lifelike tonality is possible. The included diagram shows what could be “next” in audio for music, movies, virtual reality (VR), and training simulation: a 10-loudspeaker layout that is a hybrid of Ambiophonics for an accurate front stage, where our hearing is most acute, and modified first-order Ambisonics, for full-sphere ambience (isotropic). Briefly, Ambiophonics turns stereo “inside-out,” acting as virtual headphones––but comfortably and with no in-head sounds or pinna confusion for frontal voices––to present a 120-degree-wide image with localization accurate ± 5 degrees. PerAmbio 3D/2D satisfies six listeners in home theatre environments, although only two are on the Ambiophonic plane. For compatibility, moving back 26 percent of the loudspeaker diameter satisfies ITU 5.1 angles. Two other flavors of Ambiophonics compatibly play legacy libraries, both user and content provider, of stereo and 5.1/6.1 2D surround. Research is reported in AES preprint #5934 “Scalable Tri-play Recording For Stereo,” ITU 5/1.6/1 2D, and “Periphonic 3D (With Height) Compatible Surround Sound Reproduction.” Presented at AES San Francisco in October 2004 will be the spatial aspects and microphone array for future-proof 2D and 3D recordings, releasable in 5.1/6.1 2D, PerAmbio 3D/2D, or stereo. More info is available from the Ambiophonics Institute (www.ambiophonics.org) or Filmaker Technology (www.filmaker.com), developer of the technology.
Robert E (Robin) Miller III, AES, SMPTE, BSEE, FilmakerTechnology / Filmaker Inc., Bethlehem Pennsylvania
Editor-In-Chief and Publisher Gary Reber Comments:
I thank you both for your contributions for the dialogue that is now occurring throughout professional circles. I am concerned about the ITU referenced 5.1 angles, as they do not support imaging-specific 360-dgree holosonic soundfield creation. However, I plan on studying the Periphonic 3D With Height recommendation.