On Thu, 16 Apr 2009 09:24:38 -0400, "Arny Krueger"
wrote:

I was thinking about doing some dummy head recording and
the effect on frequency response
of using an electret capsule in a model of an ear,
compared to just placing it on the surface of a
head-sized sphere.

Dummy head recording is very old news.

It can only be reasonably be played on headphones.

Any thoughts before I start moulding body parts in
plaster?

Do some homework, first. Google gives 100,000 hits for "dummy head
recording".

But not much on dummy head recording using a modeled ear cavity.

If you want to go a little beyond a glib put-down, Google has
interesting stuff on "ear acoustics" such as:

"Theoretical and applied external ear acoustics
Authors: B B Ballachanda
The external ear (pinna and earcanal) plays a major role in
transforming acoustic signals from free field to the tympanic membrane
in humans. It acts as a filter to reduce low frequencies, a resonator
to enhance mid frequencies (2.0 to 7.0 kHz), and a direction-dependent
filter at high frequencies to augment spatial perception. The external
ear transfer function is altered by variations in the physical
dimension of the external ear either due to individual differences or
due to mechanical obstructions such as blockages, hearing aid
placement, perforation of the tympanic membrane, and use of insert
earphone. It is significant that any change in the characteristics of
the acoustic signal can produce considerable disparity in within- and
between-individual responses. The present paper examines published
studies on sound pressure transfer function provided by the external
ear in humans.
Journal of the American Academy of Audiology"

The microphone you use will already be in a housing, designed to suit
the particular transducer used. Its "ear" if you like. So you'd be
putting an ear inside another ear. Maybe pointless? But this
shouldn't stop you trying, if the subject interests you.