In addition to loudness and latency differences, there is even a frequency-specific effect due to the shape of the head and in particular your ear (your pinna t

In addition to loudness and latency differences, there is even a frequency-specific effect due to the shape of the head and in particular your ear (your pinna to be precise). This is actually probably the reason why our ears have the weird shape they do. This is different for every person, which means that headphone-based simulated spatial audio can never be perfect.