Gene Hunn wrote:

>There is a device that actually digitizes the sound, computes it at a
>lower frequency without altering the elapsed time, then plays it into your
>ear. Dave Nunnallee had one a couple of years ago. In this way you can
>"hear" those lost higher frequencies apparently.

I'm a bit behind the curve on this thread as I am working off-line these
days, picking up Tweeters digests from Dan Victor's web page. As there
appears to be some interest in this subject, I am re-sending the following
message which I posted privately to several folks earlier on this thread:
____________

As a youngster, I was taken to the rifle range weekly by my father, where we
shot and shot and shot, without hearing protectors of course. My interests
have long since evolved to birding, but as a result of the shooting my
high-pitch hearing is poor. (Interesting note: my brain has apparently
adjusted for the hearing loss by making my low-pitch hearing very acute,
which is great for owling but really bad for boom-boxes!)

For several years I have been using a device called the Songfinder. This
device costs approximately $1000, weighs a little over a pound, runs on 6
rechargable AA batteries, and is worn with a strap over the shoulder. A
lightweight earphone set is worn, with jacks plugged into the Songfinder.
Each ear piece has a mike on the outside and a speaker on the inside next
to the ear. The mike picks up the natural bird sounds, and transmits them
analog to the Songfinder box where the sound is converted to digital.
Depending on your manual switch settings, the digital sound frequency is
cut in half or in third, thus lowering the frequency one or two octaves.
The sound is converted back to analog and is sent up a separate wire to the
small speakers in the earphones. This all happens in real time, and since
the input mikes are located by each ear the user can recognize direction
quite well. Volume can also be adjusted manually.

Most people with high-pitch hearing loss retain pretty good hearing at lower
frequencies, thus the user is able to hear bird songs clearly at a
lower-than-normal pitch. For me, this is a godsend, and like Nancy's father
my biggest problem now is getting used to the symphony of bird sounds which
I hadn't heard for years! At one octave lower, some warblers tend to sound
rather like fast Robins, but most bird songs still sound remarkably like the
originals and are very recognizable.

The last address I had for Songfinder was:
Mr. Lang Elliott
NatureSound Research
P.O. Box 84
Ithaca, NY 14851

phone (607) 257-4995

--------------------
April 29: An added note - I returned several days ago from a week in SE
Arizona where I used the SongFinder extensively. As usual, it provided a
wonderful tool for me to hear the many bird songs which for me are usually
silent. However, as I have noted before while birding with others who have
acute hearing, the SongFinder does not provide as much sensitivity for the
faint calls and songs as can be heard by an individual with excellent
hearing.

BTW, Southeast Arizona is in the grip of a serious drought. Virtually no
spring wildflowers, most streams including Cave Creek and Madera Canyon are
dry, and bird populations and diversity are low. Very enjoyable trip
nonetheless.

Dave Nunnallee
dnun461 at ecy.wa.gov
Bellevue, WA