The amount of spatial redundancy for recordings from a spherical microphone array is evaluated using a low delay lossless compression scheme. The original microphone signals, as well as signals transformed to the spherical harmonics domain, are investigated. It is found that the correlation between channels is, as expected, very high for the microphone signals, in several different acoustical environments. For the signals in the spherical harmonics domain, the compression gain from using inter-channel prediction is reduced, since this conversion results in many channels with low energy. Several alternatives for reducing the coding complexity are also investigated.
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