Before revision: The head-related transfer function is involved in resolving the cone of confusion, a series of points where ITD and ILD are identical for sound sources from many locations around the 0 part of the cone.
After revision: The head-related transfer function is involved in resolving the cone of confusion, a series of points where Interaural-Time Differences (ITD) and Interaural Level Differences (ILDs) are identical for sound sources from many locations around the 0 part of the cone.