Enhancement of spatial audio signals by modulated decorrelation

A non-transitory medium having stored thereon instructions for controlling one or more devices for:

• receiving an input audio signal that includes Nr input audio channels, the input audio signal representing a first soundfield format having a first soundfield format resolution, Nr being an integer ≥2;
• applying a first decorrelation process to a set of two or more of the input audio channels to produce a first set of decorrelated channels, the first decorrelation process maintaining an inter-channel correlation of the set of input audio channels;
• applying a first modulation process to the first set of decorrelated channels to produce a first set of decorrelated and modulated output channels;
• and
• combining the first set of decorrelated and modulated output channels with Nr undecorrelated channels to produce an output audio signal that includes Np output audio channels, Np being an integer >3, the Np output channels including the Nr undecorrelated channels corresponding with lower-resolution components of the output audio signal and the decorrelated and modulated output channels corresponding with higher-resolution components of the output audio signal;
• wherein at least one of the Nr undecorrelated channels is produced by applying a scale factor to one of the Nr input audio channels.

An audio signal processing device, comprising:

• an interface system;
• and
• a controller capable of:
• receiving, via the interface system, an input audio signal that includes Nr input audio channels, the input audio signal representing a first soundfield format having a first soundfield format resolution, Nr being an integer ≥2;
• applying a first decorrelation process to a set of two or more of the input audio channels to produce a first set of decorrelated channels, the first decorrelation process maintaining an inter-channel correlation of the set of input audio channels;
• applying a first modulation process to the first set of decorrelated channels to produce a first set of decorrelated and modulated output channels;
• and
• combining the first set of decorrelated and modulated output channels with Nr undecorrelated channels to produce an output audio signal that includes Np output audio channels, Np being an integer ≥3, the Np output channels including the Nr undecorrelated channels corresponding with lower-resolution components of the output audio signal and the decorrelated and modulated output channels corresponding with higher-resolution components of the output audio signal;
• wherein at least one of the Nr undecorrelated channels is produced by applying a scale factor to one of the Nr input audio channels.