The skull has a number of open air-filled chambers, which could in principle act as resonators: the paranasal sinuses in the bones surrounding the nasal cavity; two large maxillary sinuses in the cheek area; two frontal sinuses just above the orbits; several small sinuses between the orbits; and two sphenoid sinuses at the base of the skull. Certainly professional singers report resonant-like sensations in the frontal sinuses when they are producing a note with maximum carrying power.
If you know the volume of these chambers (from MRI scans), then it is easy to calculate what the respective resonant frequencies are; however, note that they are mostly all lined with a mucosal layer, and also prone to filling as a result of various infectious agents; thus, to be certain, you would probably have to rule out factors such as sinusitis and fungal infections.
I doubt that you'll cause anyone's head to explode, but you would obviously have to use bone-conducted signals, and this will rule out relatively low frequencies at levels greater than about 50-60 dB (HL), as vibrotactile cues will confound any reports of resonance you might get.
On 12 Mar 2012, at 17:55, Gordon, Michael wrote: