Ambisonic Blur

This tool controls the spatial resolution of the $L^\text{th}$ degree Ambisonic sound scene while preserving its overall energy. Implementation is described in¹. The user can control the “blurriness” of the scene from $0\%$ to $100\%$ by gradually varying the maximum degree retained for the output sound scene and thus the spatial resolution. This is done by muting the higher degree components as the blur parameter $\alpha$ goes from $0\%$ to $100\%$ with weighting functions

as shown in Fig.1. Thus, when the components of degree $l_1 \leq L$ are muted, the remaining components of degree $l \leq l_1$ are amplified in accordance to keep the global energy of the sound scene.

The slope of the weighting functions is controlled by a parameter $\tau$.

Compilation parameter

• L: maximal Spherical Harmonics degree (i.e., Ambisonics order, $L \geq 0$)

Inputs / Outputs

• Inputs: $(L+1)^2$
• Outputs: $(L+1)^2$

User Interface

Element	OSC	Min value	Max value
Blur proportion $\alpha$ ($\%$)	alpha	0	100
Steepness $\tau$	tau	0.25	1