Headset microphones for recording speech intensity

[Reggie Weece <weece@xxxxxxxx>]

Dear list members,

As part of my research, I am looking for a reliable way to record
human speech such that changes in the recorded levels are a reflection
of changes in the speaker's voice, and not simply due to the speaker
turning their head or moving away from the microphone.  This naturally
suggests using some sort of headset microphone, but our previous
experiments with these have still given rise to too much "play" in the
positioning of the microphone relative to the mouth.  Does anyone know
of reliably rigid headsets/mountings for this type of application, or
of any other workarounds for this problem?

Thanks,
Reggie