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AES

Audio Engineering Society

24th International Conference on Multichannel Audio
June 26-28, 2003, Banff, Canada

 

SURROUND AMBIOPHONIC RECORDING AND REPRODUCTION

by Ralph Glasgal

AMBISONICS + AMBIOPHONICS (Fig. 8)

In the absence of a three ball Ambiophone or impulse response expertise, it is possible to make live recordings using a single Ambiophone facing forward to catch the stage and an Ambisonic WXYZ coincident microphone just behind it to only record hall ambience in all dimensions. The Ambisonic array must be baffled to prevent it from picking up frontal direct sound. Six media channels are also required to store this version of periphonic sound.

Instead of an Ambiovolver an Ambisonic decoder is required to deliver the ambience to the surround speakers. Normally, Ambisonic surround speakers must be symmetrically arranged about the listening spot. However, when only ambient sound is being handled Ambisonically, the requirements are less stringent. Also the more speakers used the better the results

Fig. 8 Ambisonic Techniques Can Be Used to Provide Surround Ambience With Height

Since Ambisonic technology and some hardware and software has been available since the 70s, this route may be more attractive to researchers than the Ambiovolver approach.  The advantage of the Ambiovolver however, is that hall ambience need not be recorded during the performance.  There is also the complexity of the various Ambisonic four- capsule microphones and control units.  Ambisonic techniques are also often used to capture  hall impulse responses.

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