2.1 Introduction

Spatial audio processing and coding are not topics that can be treated in an isolated fashion. Spatial audio signals have properties which are related to the specific audio playback system over which the signals are intended to be reproduced. Further, specific properties also result from the microphone setup used if spatial audio signals are directly recorded. In addition to discussing spatial audio playback systems, recording is very briefly discussed. Additionally, conventional audio coding and matrix surround are reviewed.