There are many complaints of single individuals about disturbing
low-frequency noise while sound level does not even approach the
admissible limit. Who can point such suffering poeple to measurement
that might be closer related to their perception, maybe something like a
modulation audiogram? I suggest a carrier of 100 Hz being 100% modulated
with frequencies varying between 20 Hz and 1 Hz. Some of the sufferings
are pondering on whether or not to buy expensive LF equipment in order
to provide evidence for the existence of a real hum. I guess, this
cannot be recommended because the ear does not physically resolve
infrasound but the brain is very sensitive to modulation in that region.
So we rather need adequate audiometry based on modulation, too. Don't
we?
http://iesk.et.uni-magdeburg.de/~blumsche/
