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Audio-engine: reproduction

The output of the encoding unit is a complete representation of the periphonic soundfield in an ambisonic format. The decoding unit recreates the soundfield in an inverse process to the ambisonic encoding. Therefore, decoder and encoder share the plugin that defines the set of encoding rules to use.

The decoding process depends on the actual loudspeaker-layout. This layout is passed to the decoder via a configuration-file. Therefore, the decoding unit can be used to decode an ambisonic soundfield to virtually any loudspeaker-layout.

It is possible to rotate the whole soundfield to adjust the ``front'' direction to the actual orientation of the audience.

Basic ambisonic decoding works only very well in a small sweet spot. This is highly desirable in a production environment, when the mixing engineer is seated within this small area to obtain the best possible result.

However, if a periphonic soundfield is to be recreated for a large audience (as it is in concert situations), most of the listeners will be outside this sweet spot. It is therefore necessary to enlargen the sweet area of good reproduction at the expense of the excellent reproduction quality in the original sweet spot. The largest sweet area can be obtained by the so-called in-phase-Decoding.

To optimize the trade between large reproduction area and quality, it is possible to crossfade between the two decoding algorithms.


next up previous
Next: Frontends Up: the IEM-Cube Previous: Audio-engine: production
Johannes M Zmoelnig 2002-09-17