So you think you can do a decent trackstand?



On 2007-11-17, [email protected] <[email protected]> wrote:
> On Sat, 17 Nov 2007 15:00:50 +0100, Jasper Janssen
><[email protected]> wrote:
[...]
>>Not actually true. The shape of our ears greatly influences our hearing in
>>open air. Not so much when you put on headphones (which eliminate those
>>influences) and start testing for hearing deficiencies, of course, but the
>>outer ears are for directionality and a certain amount of
>>preamplification.
>>
>>Jasper
>
> Dear Jasper,
>
> Can you link to a picture of a human ear and explain in more detail
> how the shape does anything useful from the point of view of an
> audiologist?
>
> After all, the tiny functional opening is rather well-shielded from
> most of the bizarre and convoluted structure.
>
> Primate ears have evolved in the direction of ornamentation, useful in
> itself for social purposes, but not their original function--much like
> antlers in deer, which have moved away from the original purpose of
> defense to a social function.

I think the ear's odd shape is partly what gives it different frequency
responses in different directions. This different frequency response is
supposed to be used by the brain to determine the directions sounds are
coming from.

It can be measured (for a "standard" ear) and built into sound
processing software used in PC sound cards to simulate sounds coming
from different directions. It's called "HRTF":

http://en.wikipedia.org/wiki/Head-related_transfer_function

Of course the first things you do if you're trying to simulate a sound
from a particular direction is just apply a volume difference between
the two loudspeakers. For a better effect, you also apply the correct
time delay. HRTF is the icing on the cake, although I have never found
it works very well on me. YMMV.
 
A Muzi <[email protected]> wrote:

> [email protected] wrote:
> > Jasper Janssenwrote:
> >> [email protected] wrote:
> >>
> >>> our external ears make no practical
> >>> difference in hearing,
> >> Not actually true. The shape of our ears greatly influences our hearing in
> >> open air. Not so much when you put on headphones (which eliminate those
> >> influences) and start testing for hearing deficiencies, of course, but the
> >> outer ears are for directionality and a certain amount of
> >> preamplification.
> >>
> >> Jasper
> >
> > Dear Jasper,
> >
> > Can you link to a picture of a human ear and explain in more detail
> > how the shape does anything useful from the point of view of an
> > audiologist?
> >
> > After all, the tiny functional opening is rather well-shielded from
> > most of the bizarre and convoluted structure.
> >
> > Primate ears have evolved in the direction of ornamentation, useful in
> > itself for social purposes, but not their original function--much like
> > antlers in deer, which have moved away from the original purpose of
> > defense to a social function.
> >
> > (It's hard to claim that deer grow antlers for defense when they shed
> > them for half the year--the antlers are now used primarily for
> > impressing other deer and then for ritualized mating combat when
> > antlers prove equal, not fending off predators. The addition of new
> > points on a yearly basis emphasizes this.)
> >
> > In primates, the loss of all but the faintest trace of motion is
> > significant--our ears have lost most of their original amplification
> > and directionality.
> >
> > (Try to hear better by wiggling your ears. If you actually want to
> > hear better, you cup your hand over that badly shaped thing on the
> > side of your head, which has scarcely any functional amplification.)
> >
> > No other ears even faintly resemble the silly things flattened against
> > our heads that we use to support our glasses. The closest thing is the
> > ear of a basset hound, which favors sheer size rather than naked but
> > useless ornamentation.
> >
> > Most of the human ear's silly contours are well-shielded from the
> > actual opening. The curved channel leading from the outer external ear
> > was once a useful amplifier, but has been so distorted that it no
> > longer has any significant function.
> >
> > You can test this by sticking a finger (or some chewing gum) into the
> > deep part of that channel and blocking it off. You'd be hard pressed
> > to notice any difference in your hearing. In fact, moving the rest of
> > your hand out of the way will make far more difference to your hearing
> > than the tip of your finger blocking what was once a useful channel.
> >
> > Acoustically, the bulk of our external ear has become useless. Another
> > way to understand this is to reverse things--imagine trying to turn
> > the ear into a trumpet. The effect on the sound of the stuff way off
> > to the side of the opening would be practically nil. The side of your
> > head provides about as much functionality.
> >
> > An acoustical function for the ear-lobe would contradict all this, but
> > the ear-lobe is actually just the fading and now useless remnant of
> > the support and muscle structure that you can see in the same place on
> > a dog's ear--which is particularly absurd in a basset hound:
> >
> > http://home.comcast.net/~carlfogel/wsb/media/286143/graphic_pub.jpg
> >
> > Despite the beautiful pose, that's ornamentation, not audiology. If
> > anything, it interferes with the dog's hearing.
>
> Like seatstays, you can hang things from ears.

http://store.cinemasecretsonline.com/wo308.html

--
Ted Bennett
 
On Wed, 14 Nov 2007 23:05:05 -0700, [email protected] wrote:

>I stumbled across this fellow in the New York Times archives and
>tracked him down:
>
> http://www.showhistory.com/KilpatrickOneLeggedBicycle.html
>
>Here's a typical newspaper announcement:
>
>
>http://query.nytimes.com/gst/abstract.html?res=9E03E6D81038E533A6575BC0A9609C94679ED7CF
>
>On an unrelated note, note the "brake" bridge with no hole that
>connects the seat stays in the circus picture.
>
>As far as I know, the equipment pre-dates rear caliper brakes, and the
>seat-stays in the picture are much too wide to trap a tire, the two
>usual explanations for such bridges. It may be worth looking into old
>pictures to see how early seat-stay and chain-stay bridges appeared.
>
>Cheers,
>
>Carl Fogel

This thread is going to the dogs:


http://www.nostalgic.net/index.asp?S=arc/photos/1890's+dog+on+a+bike.jpg

It's an 1890's bike with typical seat-stay and chain-stay bridges.

The bicycle's owner must have been tall enough to consider his model a
dachshund--look at that head-tube! It's easily as big as the crank.

***

I count three naked 1897 seat-stay bridges, second from left, fourth
from left, and second from right, in front of the Davenport
courthouse:


http://www.nostalgic.net/index.asp?S=arc/photos/Davenport+Courthouse+1897+with+bikes.jpg

***

A close look reveals a chain-stay bridge on this drawing of an 1894
Union bicycle:


http://www.nostalgic.net/index.asp?S=arc/ScannedLit/TheBicyclingWorld-3-16-94/TBW-3-16-94pg06.jpg

The marketing department could hardly restrain itself:

"Keep Up with the Times! You Can Do It On a Union!"

"What ho, cycler! Why waste your muscle on a RATTLETRAP? The UNION
gives a FULL RETURN of speed for EVERY OUNCE of power supplied."

"There is No Click or Creak."

"Every bearing is Firm and Free."

"The frame is Tight and True."

"If you seek a better, your search is hopeless."

The drawing looks authentic, right down to the lacing of the 32 front
and 36 rear. The price is discreetly omitted.

Cheers,

Carl Fogel
 
On Sat, 17 Nov 2007 10:35:06 -0700, [email protected] wrote:

>Dear Jasper,
>
>Can you link to a picture of a human ear and explain in more detail
>how the shape does anything useful from the point of view of an
>audiologist?

Why don't you link to an ear-witness account by someone who's lost the
external ear without damaging the inner structure, saying that it's
exactly the same as before.

>After all, the tiny functional opening is rather well-shielded from
>most of the bizarre and convoluted structure.

Yes, most. Not all.

>Acoustically, the bulk of our external ear has become useless. Another
>way to understand this is to reverse things--imagine trying to turn
>the ear into a trumpet. The effect on the sound of the stuff way off
>to the side of the opening would be practically nil. The side of your
>head provides about as much functionality.

And yet the inner part of the outer ear makes the whole thing
significantly different from a 3 mm hole in the side of your head.

>An acoustical function for the ear-lobe would contradict all this, but
>the ear-lobe is actually just the fading and now useless remnant of

Well, no ****** is the earlobe acoustically insignificant.

Jasper
 
On Sun, 18 Nov 2007 18:06:49 +0100, Jasper Janssen
<[email protected]> wrote:

>On Sat, 17 Nov 2007 10:35:06 -0700, [email protected] wrote:
>
>>Dear Jasper,
>>
>>Can you link to a picture of a human ear and explain in more detail
>>how the shape does anything useful from the point of view of an
>>audiologist?
>
>Why don't you link to an ear-witness account by someone who's lost the
>external ear without damaging the inner structure, saying that it's
>exactly the same as before.

[snip]

Dear Jasper,

As a boy, I had extensive bilateral external ear surgery.

It had no noticeable effect on my hearing, much less any significant
effect. The violin sounded the same, before and after. No differences
noted before or after hearing people speak.

In fact, I had no hearing problems during the two weeks that I wore a
handsome white turban of bandages. Despite their dangling bedsheet
ears, basset hounds actually have excellent hearing.

One ear later required more surgery, since keloid scar tissue was
pushing it off my head and causing trouble with my glasses.

Again, no noticeable effect on my hearing.

Years later, I talked to audiologists at my clients' offices and
learned that people are just as prone to fantasizing about their
hearing as they are about all their other health problems. Trying to
figure out what's real and what's imagined occupies much of their
time, just as RBT's bike-fit threads often hint that there are more
princesses than peas out there.

Regrettably, the only absolute test is indeed bilateral ear amputation
with testing before and after. The test still wouldn't be much good,
since it can't be performed as a blind test--after an amputation, the
suject can't help paying more attention to his hearing, which distorts
his perception.

Nevertheless, the majority of single-ear amputatees report no hearing
changes, and testing usually fails to confirm the understandable
complaints from the minority--volume, frequency, and our rather
pitiful directional sense remain well within the normal range, along
with the more complicated measures.

This is hardly suprising, since the functional ear is inside the
skull.

Here's an abstract of a small study of patients with large single-ear
blood-vessel malformations, some of which involved amputation, while
most merely reduced the huge growth right next to the external ear
opening. Of the 29 patients, 8 had amputations with one kind of
treatment, while 6 had amputations with another approach.

"Of 22 of 29 treated patients [14 of 29 had amputations] surveyed, 81
percent were satisfied with their management. Hearing was either
unaffected (n = 15) or diminished (n = 5); two patients noted
decreased sound localization.


http://www.plasreconsurg.com/pt/re/prs/abstract.00006534-200504010-00001.htm;jsessionid=HQ2QTz63LBhxJcvPQG7qN31qrkpPSlfgfkTrRcv7HZYkbc8Xqf54!1600246195!181195629!8091!-1

"Management" in this case means which treatment was chosen for the
large growths, the primary concern of both patients and doctors.

In other words, 15 of 29 people with long-term, painful external ear
problems noticed no effect on their hearing, 5 noticed diminished
hearing (hardly significant with the age-range of 1 to 55 and the
follow-up time of 5~6 years), and 2 thought that they had some trouble
with directional hearing--again, most likely a psychological effect,
since blind tests of directional hearing tend to show why we use our
eyes instead of our ears to navigate.

The effect on hearing was essentially dismissed in the study. Unless a
growth actually blocks the external opening, no significant effect is
expected.

In fact, the lack of effect is highlighted by the fact that none of
the 15 patients who had large ear growths removed without amputation
reported improved hearing.

Luckily, you don't have to cut your ears off to test things.

Stick two wads of damp kleenex in the outer channels of your ears,
blocking them, and see if you can tell any difference.

If you're still unconvinced, go to an audiologist and ask him to test
your hearing with and without the channels blocked.

Cheers,

Carl Fogel
 
On 2007-11-18, [email protected] <[email protected]> wrote:
[...]
> In fact, I had no hearing problems during the two weeks that I wore a
> handsome white turban of bandages. Despite their dangling bedsheet
> ears, basset hounds actually have excellent hearing.

Everything you're saying about ears is most interesting. After my
experience with HRTF filters I'm quite ready to believe that the
frequency response of my pinnae has little or nothing to do with
directional perception.

But don't proper dogs have upright ears that they can swivel? I had
always assumed that the floppy ears of basset hounds and other dogs are
the result of domestic breeding, perhaps designed to make them look less
wolf-like.
 
On Sun, 18 Nov 2007 17:44:59 -0700, [email protected] wrote:

>With that point settled, we can move on to less developed canines,
>such as wolves, coyotes, and foxes, all of which have upright, mobile
>external ears, nicely shaped for catching sound waves and funneling
>them into the internal ears.

First, I have to note that you know way too much about some subjects
Carl.

Second, I long for the many muscle ears of a cat or dog, able to
swivel and grab sounds from a wide area... or even two separate areas
at once.

I think they'd be easier to create artificially than three arms, which
is my other goal for human refinement.
 
On Mon, 19 Nov 2007 03:27:35 GMT, still just me
<[email protected]> wrote:

>On Sun, 18 Nov 2007 17:44:59 -0700, [email protected] wrote:
>
>>With that point settled, we can move on to less developed canines,
>>such as wolves, coyotes, and foxes, all of which have upright, mobile
>>external ears, nicely shaped for catching sound waves and funneling
>>them into the internal ears.
>
>First, I have to note that you know way too much about some subjects
>Carl.
>
>Second, I long for the many muscle ears of a cat or dog, able to
>swivel and grab sounds from a wide area... or even two separate areas
>at once.

Dear Vey,

First, everyone should know as much about basset hounds as possible.
Ignorance forced T.S. Eliot to revise his original line to something
much weaker:

"I do not know much about gods; but I think that the basset hound/ Is
a strong brown god . . ."

Second, you could long even more for the many muscle ears of a horse
or rhinoceros, since they have better muscular control than cats and
dogs, being able to flick and swivel either ear independently over a
much larger range.

The ear control of those large creatures, however, is not used just to
**** one ear toward a sound. It's useful for getting rid of annoying
insects, just like their tails, which long ago lost any balancing
function.

If you watch a cat listening for mice in the fall leaves, you'll find
that they **** their heads more than they move their ears.

This is the guy who has the external ears and muscular control for
hearing that people are thinking of:


http://video.google.com/videoplay?d...l=7&start=0&num=10&so=0&type=search&plindex=0

If the video doesn't play, there's a try-this option on the lower
right, and you can select other video formats, too.

Cheers,

Carl Fogel
 
On Sun, 18 Nov 2007 21:20:34 -0700, [email protected] wrote:

>On Mon, 19 Nov 2007 03:27:35 GMT, still just me
><[email protected]> wrote:
>
>>On Sun, 18 Nov 2007 17:44:59 -0700, [email protected] wrote:
>>
>>>With that point settled, we can move on to less developed canines,
>>>such as wolves, coyotes, and foxes, all of which have upright, mobile
>>>external ears, nicely shaped for catching sound waves and funneling
>>>them into the internal ears.
>>
>>First, I have to note that you know way too much about some subjects
>>Carl.
>>
>>Second, I long for the many muscle ears of a cat or dog, able to
>>swivel and grab sounds from a wide area... or even two separate areas
>>at once.
>
>Dear Vey,
>
>First, everyone should know as much about basset hounds as possible.
>Ignorance forced T.S. Eliot to revise his original line to something
>much weaker:
>
>"I do not know much about gods; but I think that the basset hound/ Is
>a strong brown god . . ."
>
>Second, you could long even more for the many muscle ears of a horse
>or rhinoceros, since they have better muscular control than cats and
>dogs, being able to flick and swivel either ear independently over a
>much larger range.
>
>The ear control of those large creatures, however, is not used just to
>**** one ear toward a sound. It's useful for getting rid of annoying
>insects, just like their tails, which long ago lost any balancing
>function.
>
>If you watch a cat listening for mice in the fall leaves, you'll find
>that they **** their heads more than they move their ears.
>
>This is the guy who has the external ears and muscular control for
>hearing that people are thinking of:
>
>
>http://video.google.com/videoplay?d...l=7&start=0&num=10&so=0&type=search&plindex=0
>
>If the video doesn't play, there's a try-this option on the lower
>right, and you can select other video formats, too.
>
>Cheers,
>
>Carl Fogel


Sorry, Bob, not Vey--I confused two posts in different windows.

C.F.
 
On Sun, 18 Nov 2007 20:34:23 -0800 (PST), Marian
<[email protected]> wrote:

>
>> Here's the first example that I've found, a shaft-drive with a bridge
>> connecting the chain-stays:
>>
>> http://www.nostalgic.net/arc/pre1920/1900 Columbia shaft drive%...
>
>What's old is new in your 1900 Columbia Ladies' Shaft Drive bicycle
>the saddle has an ERGONOMIC CUT OUT for tender bits!!

Dear Marian,

Saddles with hopefully cut holes were actually quite common in early
bicycles, but they were known as hygenic rather than ergonomic for
reasons that I dare not explore.

Looking for a nice link about hygenic saddles, I ended up here:


http://www.momentumplanet.ca/features/role-bicycle-womens-liberation-movement

Here's more about Annie Kopchovsky, the first round-the-world woman
bicyclist:

http://www.annielondonderry.com/images/BI05ANNIE.pdf

I was prepared to embrace Annie until I saw that her itinerary led
north from New Mexico, went Trinidad and then swerved east around
Pueblo to go through La Junta on the way to Colorado Springs.

Shameless hussy!

Anyway, even a few highwheelers had those hopeful holes in seats:


http://www.eriding.net/media/photos/transport/vintage_bikes/040930_cbr_mp_his_trans_vb_521.jpg

Here's an 1889 safety with ornate holes:


http://www.eriding.net/media/photos/transport/vintage_bikes/040930_amoore_mp_his_trans_vb_022.jpg

An 1892 safety with a simple slot seat:

http://collection.rydjor.com/bikecollection/1892imp.htm

An 1896 safety, ditto:

http://collection.rydjor.com/bikecollection/1896imp.htm

An 1898, ditto:

http://collection.rydjor.com/bikecollection/1898and1.htm

A 1903 triangular hole:

http://collection.rydjor.com/bikecollection/1903tri.htm

An 1868 wooden prototype for Sheldon's RealMan saddle:

http://collection.rydjor.com/bikecollection/1868bon.htm

The classic saddle, no holes, no compromises, no compliance:

http://www.sheldonbrown.com/real-man.html

Of course, no lady could ride a conventional highwheeler, so a
sidesaddle version was invented. Unfortunately, the skirt conceals not
only indecent limbs, but what must have been a fascinating mechanism
and an even more fascinating saddle:

http://i15.tinypic.com/7wymkj9.jpg

More details here, including the need to shorten one side of the
handlebar:


http://books.google.com/books?id=Is...VoUN&sig=tmRUEfhyh2CnplviKF8Pid5rDnE#PPA43,M1

Page down past the--alas!--missing picture for more details. For some
reason, the sidesaddle highwheeler never caught on. Once this design
is revived, I feel confident that the fair sex will post more often on
RBT.

Cheers,

Carl Fogel
 
On Nov 19, 5:21 am, [email protected] wrote:
> Sorry, Bob, not Vey--I confused two posts in different windows.

Dear Carl,
that suggests that you have directional windows, to say
the least.

Sergio
Pisa
 
On Mon, 19 Nov 2007 09:05:00 +0100, "James Thomson"
<[email protected]> wrote:

><[email protected]> a écrit:
>
>> Of course, Eddy could have drilled the bridge vertically and
>> used an L-bracket if he felt the need for a fender on the indoor
>> track.
>
>*Outdoor* track! Note the grass:
>
>http://www.thespincycle.com/files/merckxMoltini.jpg
>
>Rain delayed the record attempt.
>
>http://www.classicrendezvous.com/Benelux/Merckx/Merckx_hour_B-guide_1.htm
>
>James Thomson

Dear James,

You're right, I was wrong, and I wish could provoke even more
corrections like that!

I was fooled by this picture:


http://upload.wikimedia.org/wikipedia/commons/6/61/EddyMerckxHourRecordBike2.jpg

That's a museum-style display stand that I carelessly mistook for the
actual track.

The details in the next article that you give us are fabulous:


http://www.classicrendezvous.com/Benelux/Merckx/Merckx_hour_B-guide_1.htm

To reduce weight, Merckx drilled the seatpost, handlebar, and chain,
used a titanium handlebar stem and pedal spindles, secured hollow
axles with special smaller nuts, and fitted an alloy rear cog.

He designed the frame himself and had Ernesto Colnago build it.

But even after getting it down to less than 12 pounds 2 ounces, he
left the two bridges between the chain stay and the seat stay, as your
original pictures show.

Seat-stay bridge:

http://www.thespincycle.com/files/merckxMoltini.jpg

Chain-stay bridge:


http://upload.wikimedia.org/wikipedia/commons/6/61/EddyMerckxHourRecordBike2.jpg

Maybe the bridges were useless and Eddy was simply a slave to fashion?
Great lungs and legs don't necessarily make you an engineering genius.

Or maybe they brace things just enough to be useful on a bike trimmed
down to less than thirteen pounds, even if it's only going to be
ridden on a smooth _outdoor_ track for an hour or so by a Belgian
tourist in Mexico?

My guess is that the frame would have lasted without the bridges, but
it does seem as if bracing was the only intention.

Thanks again for pointing out my mistake with such a wonderful
article!

Cheers,

Carl Fogel
 
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