The increasing popularity of Ambisonics as a spatial audio format for streaming services poses new challenges to the existing audio coding techniques. This paper seeks to evaluate timbral distortion and localization accuracy of Ambisonic audio encoded using Opus low-bitrate compression. The study was conducted for first, third and fifth order Ambisonic signals at various bitrates reproduced over a 50-channel spherical loudspeaker configuration. This study has identified how lower bitrates reduce timbral fidelity, though this changes depending on the audio content. Localization accuracy has been found to be relatively robust even at very low bitrates. The results suggest that the user experience of spatial audio streaming services would significantly improve if third order Ambisonics would be implemented over first order.
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