Thank you to everyone for your wonderful responses to the question: how do I measure resonant characteristics of the human body?
Here is a summary of those responses and the related findings.
This link to a NASA report contains approximate resonant ranges for several body parts (head, hands, chest, etc). The report cites a 1978 ISO that I was unfortunately unable to access. (ISO 2631-1978(E), Guide for the Evaluation of Human Exposure to Whole Body Vibration, ISO, 01/15/78.)
NASA also had this more general link on human performance capabilities. The report has values on everything from dark adaption thresholds, to vibration tolerances, to push off velocities in space.
Thanks to Andy Milne, Jose Ignacio Alcantara, David Smith, and Bob Masta for their suggestions.
“Tap the body part with something hard and pointy - maybe not too pointy = :) - and record the resulting impulse response”.
Since this technique was relatively low-tech and easy to do, in my lab we actually tried this. We used a hard rubber mallet (same design as physicians use to get a reflex from a person’s knee), had people tap their own heads, and recorded the impulse responses from a nearby area on the scalp. We also to impulse response measurements of the mallet. With that we were able to do an FFT on both people’s heads and the mallets, subtracted the average resonance of the mallet and had a pretty quick and surprisingly consistent measurement of people’s head resonances.
Use an MRI to determine the volume of resonant chambers of the head: i.e., “ 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.” Be careful to rule out biases in the resonance caused by the mucosal layer and any potential infections increasing amount of mucus in any of these chambers.
I haven’t tried this yet, but will next time I get on the scanner. I’d like to correlate the method above with this technique.
A warning – avoid loudly projecting frequencies around 7 Hz as they can cause gastrointestinal problems and feelings of illness.
Dr. Michael S. Gordon
Department of Psychology
William Paterson University