An audio encoder configured to encode a frame of a soundfield signal comprising a plurality of audio signals, the audio encoder comprising - a transform determination unit (203, 204) configured to determine an energy-compacting orthogonal transform based on the frame of the soundfield signal; - a transform unit configured to apply the energy-compacting orthogonal transform to a frame derived from the frame of the soundfield signal, and to provide a frame of a rotated soundfield signal comprising a plurality of rotated audio signals (E1, E2, E3); - a waveform encoding unit configured to encode a first rotated audio signal of the plurality of rotated audio signals (E1, E2, E3); - a parametric encoding unit configured to determine a set of spatial parameters (ae2, be2) for determining a second rotated audio signal of the plurality of rotated audio signals (E1, E2, E3) based on the first rotated audio signal, wherein the parametric encoding unit is configured to perform parametric encoding on a per sub-band basis and to determine a different set of spatial parameters for each of a plurality of sub-band signals of the second rotated audio signal; and - a non-adaptive transform unit configured to apply a non-adaptive transform (M(g)) to the frame of the soundfield signal to provide a transformed soundfield signal comprising a plurality of transformed audio signals (W, X, Y); wherein the transform determination unit (203, 204) is configured to determine the energy-compacting orthogonal transform based on the transformed soundfield signal, wherein the parametric encoding unit is configured to determine a second prediction parameter based on the second rotated audio signal and based on the first rotated audio signal, the second prediction parameter enabling a corresponding decoder to estimate a correlated component of the second rotated audio signal based on the first rotated audio signal; and/or wherein the parametric encoding unit is configured to determine a second energy adjustment gain based on the second rotated audio signal and based on the first rotated audio signal, the second energy adjustment gain enabling a corresponding decoder to estimate a decorrelated component of the second rotated audio signal based on the first rotated audio signal. - a transform determination unit (203, 204) configured to determine an energy-compacting orthogonal transform based on the frame of the soundfield signal; - a transform unit configured to apply the energy-compacting orthogonal transform to a frame derived from the frame of the soundfield signal, and to provide a frame of a rotated soundfield signal comprising a plurality of rotated audio signals (E1, E2, E3); - a waveform encoding unit configured to encode a first rotated audio signal of the plurality of rotated audio signals (E1, E2, E3); - a parametric encoding unit configured to determine a set of spatial parameters (ae2, be2) for determining a second rotated audio signal of the plurality of rotated audio signals (E1, E2, E3) based on the first rotated audio signal, wherein the parametric encoding unit is configured to perform parametric encoding on a per sub-band basis and to determine a different set of spatial parameters for each of a plurality of sub-band signals of the second rotated audio signal; and - a non-adaptive transform unit configured to apply a non-adaptive transform (M(g)) to the frame of the soundfield signal to provide a transformed soundfield signal comprising a plurality of transformed audio signals (W, X, Y); wherein the transform determination unit (203, 204) is configured to determine the energy-compacting orthogonal transform based on the transformed soundfield signal,