This erratum concerns the expression of acoustic particle velocity [Eq. (4)] in the original paper.1 We have mistakenly omitted a coordinate transformation term for the expression. The expression in the original paper is correct for the direction r. However, for the direction θ and ϕ, the correct equations should be as follows:
Note that the proof for here is similar to the proof for in the original paper, which is correct. Without the Wigner 3-j symbols in the expression of , the active order is not 2 N anymore. However, the truncation error also falls to an acceptable value as the truncation order increases. Figure 2 from the original paper must also be replaced with the figure given here. Note that the performance of sound intensity in the ϕ direction, similar to the θ direction, is slightly worse than that in the r direction as well due to the truncation error.
The authors very much appreciate Byeongho Jo of Korea Advanced Institute of Science and Technology for discovering this problem.