Very interesting.
from the guy in the garage. the high response does not seem to me to
be the factor here in my minds eye. time of arrival may be solved by
the brain with a multiple pass study without needing high freq. info
time resolution.=20
but there may be something going on with the result on how a low pass
filter works.
i will be booked for 2 months now but still likely will be able to
look at this in the garage.
if the plan comes together I get a second floor on that three cow
garage as well this spring.
i may be quiet for awhile but am still paying attention.
rich peet
--- In Marty Michener <> wrote:
> At 06:08 PM 4/6/02 -0500, you wrote:
> >Marty Michener wrote:
> >
> >a bunch of interesting stuff.
> >
> >
> >I have a few questions:
> >
> >What mics and headphones did he find with such high frequency
response?
> >It's not just the digital encoding that changes things, very little
> >equipment is made for going above the 20k limit by any significant
> >amount. Sennheiser, for instance seems to have only one mic that
gets up
> >there at all, the MKH 800. And it stops way short of 80khz at
50khz. And
> >it's a pretty recent mic. You would also need custom mic pre's,
special
> >analog recorders too. Even the analog recorders have cutfilters
built
> >all through them in one form or another. And headphone design
limits
> >their upper frequency too.
>
> HI Walt:
> Excellent questions. My only answer is, I think the mics and
recorder went
> nearly flat to over 120 kHz. My memory, only.
>
> I have no recall of his mentioning measurements of phase shift,
although in
> four hours he undoubtedly might have. We are talking huge,
expensive audio
> lab at Tufts, fed funding and no real budget limit. Does ONR
know "state
> of the art"? I have wondered all the same things you ask here,
but all I
> can recall is he had the mics custom built, and they worked to 120
kHz, and
> he use analog recording techniques (modified RTMA video machine???).
>
> The sad details:
>
> As this was, to my knowledge, never published (Batteau untimely
death, see
> below) it is all from a verbal conversation on or about 1965.=20
There is
> another, interfering angle - I was introduced to D.W. Batteau by an
old
> friend, Roger Payne, Post-doc from Cornell at Tufts, switching from
Barn
> Owl hearing to moth hearing to whale hearing. Roger was just about
to jump
> off the academic cliff into single-handedly creating the 'save the
whales'
> movement - Judy Collins, rock groups, original Humpback Record,
etc. He
> had enlisted me and Batteau for technical support of his acoustic
> research. So, Roger was diverting DWB from his lab hearing
analysis to the
> ocean, and into saving marine mammals.
>
> I have looked his stuff up on the web, and it is all overshadowed
by his
> next venture - inventing and publishing a dolphin conversation
maker. He
> published this work originally supported by ONR, as many of us did
in the
> 60's - basic, not applied research, or so we thought. He published
and
> demonstrated the uses of his machine. It converted human voice
sounds into
> clicks or pops or whistles played over a speaker hydrophone, so
that vocal
> commands by humans could come closer to dolphin's own natural
> communications, and demonstrated a much-increased training process
with it.
>
> Now comes the confused history. The navy decided to "possess" his
> work. The project was suddenly classified, copies of the report
were
> garnered and locked up or destroyed. You remember the late 60's,
and the
> degree you believe what actually happened today must depend on how
much of
> the paranoid "us and them" you believed, then and now. The upshot
is many
> liberals claimed that the navy was using it to train dolphins to
carry
> bombs into enemy places. he growing environmental movement lapped
it all
> up. Now "they" are coming to tap our phones, even kill us if we
know too
> much! They also claimed that when Batteau was found drowned, in
Hawaii,
> about 1968, that it had sinister "them" implications. This
discussion was
> whispered even on many college faculty meetings, because Batteau by
that
> time was in a major media battle to prevent the Navy ever using
dolphins
> for military purposes, including activists that went to jail for
midnight
> dolphin releases from federal projects. Very exciting stuff. But
some
> have even claimed Batteau's wife's boyfriend did it. All word of
mouth. It
> was hard to even puzzle it all over. Nothing was ever proven about
the
> death, and it is still listed as accidental - a guy out for a
morning run
> and swim around sunrise. We just lost a really bright guy, but, of
course
> we won the war. ( ;^))
>
> Sorry, for so much diversion, but it explains the never published
part.
>
> >So, maybe what we are talking about is actually sound that's much
lower
> >frequency, but precise measurement of the timing of the arrival of
the
> >wavefront is how it's done. Phase shift calculations in other
words.
> >Yes, digital can mess this up, but the flip side is that a
cutfilter
> >working perfectly should not. Most real life filters produce some
phase
> >shift, however, which is a timing change. I wonder if there has
been any
> >examination on just what was getting through his system? What it's
phase
> >shift was and so on.
> >
> >And if it's phase shift that's used even we old geezers can do it.
I can
> >certainly localize a sound precisely still.
> >Walt
> >
> >
>
> Not only do analog filters produce phase shift, but our digital
editing
> filters do as well. I agree with all you said, but I specifically
recall
> Batteau telling me - when you impose analog filters in the
headphone
> output, most of the 3D beamforming process is disrupted. The up-
down and
> front back stuff, probably not the methods we use to localize
sounds from a
> distance in the woods or field.
>
> I will try to contact Roger and ask about these studies. I haven't
seen
> him in decades. If anyone on the list has his email, and would
send it to
> me privately, I think he is living now in Vermont, or was it
England? I
> could probably find out from his ex-wife, Katy Boynton Payne, at
Cornell,
> and now of elephant communication fame.
>
>
> Marty Michener
> MIST Software Associates
> 75 Hannah Drive, Hollis, NH 03049
>
> coming soon : EnjoyBirds bird identification software.
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