What Is That Music?

The mark of great music is that you will always remember where you were and what you were doing when you first heard it.

In early 1977 I was a young First Lieutenant in the Army, training at Aberdeen Proving Ground, Maryland. I had flown up there to attend 3-months of Active Duty for Training. It was winter, but on one weekend when the weather promised to be beautiful, several of us piled into a car and headed South to Washington, DC. None of us had been to DC before, so the trip was one of discovery and high expectations. Smithsonian_Air_and_Space_Museum

For a space and aviation enthusiast like myself, the long-anticipated highlight of the trip was the chance to see the newly opened Smithsonian Air and Space Museum, and to see my first Imax movie, which happened to be “To Fly”.

In the dim light of the large sloping theater, we waited for the movie to begin. Meanwhile, music was softly playing.

You know how when you’re at a restaurant or bar and someone is playing, you’re not necessarily aware of the music per se. It’s just part of the ambiance, the background. But as that music began, it started with deep strings, rhythmically, methodically stroking through the music.

Deep bass notes have always thrilled me. I am a player of clarinets, which have no bass properties to speak of, so perhaps it is the novelty of bass that so captures my imagination. And so it had slowly begun to work on me, that anonymous music.

It was clearly classical, most likely some well orchestrated version of what must have originally been chamber music. As I listened ever more attentively, the music built on itself  and added complexity which maintained and then grew my interest. I had never heard it before, and neither had my friends, but I began questioning myself, “What is this music?”

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Excerpt in the key of D

After over four minutes, when you would think the pace and melody would be becoming somewhat worn, the composer threw in some accidentals, which frankly shocked me, as they must have the music’s first listeners. There was a string of four eighth notes, and one of them sounded flat, while its pairing just two notes away was not. What is this, I thought? And then in the next measure it was repeated, so it certainly wasn’t a mistake. It was an intentional musical device, and one that I loved for its novelty.

It was as if the composer had been holding back for that subtle surprise until near the end of the piece. Just as you thought you knew what to expect, something new appeared in the melody.

Strangely, I left that theater thinking as much about that mysterious theatrical prelude as about the movie. And for an aviation enthusiast, that’s saying a lot.

Before long, I began to hear that piece elsewhere, and with increasing frequency. In fact, the music enjoyed a burst of popularity starting in the early 1970s, the same period when I first heard it.

If you haven’t guessed by now, I’m talking about Johann Pachelbel’s Canon in D. It is now so well known that it has its own web site. The following video featuring Canon in D was compiled by “diemauerdk”.

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According to the Internet, Canon in D first became available to the masses through a 1970 recording, reportedly by the French musician Jean-Francois Paillard. Oddly, even though it was written in about 1680, it was not published until 1919. I have no doubt that its rise in popularity was due in no small part to the large audiences exposed in the iMax theater at the Smithsonian Air and Space Museum. The fact that it was the main theme of the 1980 popular movie, Ordinary People, only helped to propel it to mainstream consciousness.

On viewing the piano sheet music it’s easy to spot where the usual C#  F# structure of the key of D is flatted to produce an appealing effect. The four notes of note, if you will, are D Cnatural B C#. To an ear accustomed to hearing C# throughout most of the piece, a Cnatural sounds flat; but in a delightfully unexpected way.

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I consider myself lucky to be one of the first Americans to hear what was to me new music, and to appreciate that it was a very special work indeed. However, I must wonder; three hundred years from now, do you think any works from present day artists will be “discovered”, and enjoy an almost universal popularity?

 

 

Cold Water Regulator Blues

It’s a black art, the making of scuba regulators for use in polar extremes; or so it seems. Many have tried, and many have failed.

Once you find a good cold water regulator, you may find they are finicky, as the U.S. Navy recently discovered. In 2013 the Navy invested almost two hundred hours testing scuba regulators in frigid salt and fresh water. What has been learned is in some ways surprising.

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Looking at a pony bottle that saved a diver when both his independent regulator systems free-flowed at over 100 feet under the thick Antarctic ice.

DSCN3557cropThe Navy has been issuing reports on cold water regulator trials since 1987. In 1995 the Navy toughened its testing procedures to meet more stringent diving requirements. Reports from that era are found at the following links (Sherwood, Poseidon).  (Here is a link to one of their most recent publicly accessible reports.)

The Smithsonian Institution and the Navy sent this scientist to the Arctic to help teach cold water diving, and to the  Antarctic to monitor National Science Foundation and Smithsonian Institution funded trials of regulators  for use in the under-ice environment. What those studies have revealed have been disturbing: many regulator models that claim cold water tolerance fail in the extreme environment of polar diving.

The Navy Experimental Diving Unit (NEDU) has developed testing procedures that are more rigorous than the EN 250 tests currently used by European nations. (A comparison between US Navy and EN 250 testing is found on this blog). All cold water regulators approved for U.S. military use must meet these stringent NEDU requirements.

Nevertheless, we learned this year, quite tragically, that the Navy does not know all there is to know about diving scuba in cold water.

For example, what is the definition of cold water? For years the U.S. and Canadian Navies have declared that scuba regulators are not likely to freeze in water temperatures of 38° F and above (about 3° C). (The 1987  Morson report identified cold water as 37° F [2.8° C] and below). In salt water that seems in fact to be true; in 38° F scuba regulators are very unlikely to fail. However, in fresh water 38° F may pose a risk of ice accumulation in the regulator second stage, with resultant free-flow. (Free-flow is a condition where the gas issuing from the regulator does not stop during the diver’s exhalation. Unbridled free flow can quickly deplete a diver’s gas supply.)

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The regulator on the left free-flowed, the one on the right did not.

While a freshly manufactured or freshly maintained regulator may be insensitive to 38° F fresh water, a regulator that is worn or improperly maintained may be susceptible to internal ice formation and free-flow at that same water temperature. There is, in other words, some uncertainty about whether a dive under those conditions will be successful.

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An isolator valve that can be shut to prevent loss of gas from a free flowing regulator.

That uncertainty can be expressed by a regulator working well for nine under-ice dives, and then failing on the tenth. (That has happened more than once in Antarctica.)

That uncertainly also explains the U.S. Antarctic Program’s policy of requiring fully redundant first and second stage regulators, and a sliding isolator valve that a diver can use to secure his gas flow should one of the regulators free flow. There is always a chance that a regulator can free flow in cold water.

A key finding of the Navy’s recent testing is the importance of recent and proper factory-certified maintenance.  Arguably, not all maintenance is created equal, and those regulators receiving suspect maintenance should be suspected of providing unknown performance when challenged with cold water.

This finding points out a weakness of current regulator testing regimes in the U.S. and elsewhere. Typically, only new regulators are tested for tolerance to cold water. I know of no laboratory that routinely tests heavily used regulators.

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Weddell seal on the Antarctic sea ice. Photo copyright Samuel Blanc. (From Wikimedia Commons).

Considering the inherent risk of diving in an overhead environment, where access to the surface could be potentially blocked by a 1400 lb (635 kg), 11 foot (3.4 m) long mammal that can hold its breath far longer than divers can, perhaps it is time to consider a change to that policy.

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About to descend through a tunnel in 9-feet of ice on the Ross Ice Shelf.

 

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A huge Weddell Seal blocks the diver’s entry hole. He looks small here, but like an iceberg, most of his mass is underwater.

 

 

Cold Water Scuba Regulator Testing — U.S. Navy vs. EN 250

Under thick ice in the Ross Sea, near McMurdo, Antarctica.

When scuba diving under 3-m thick polar ice with no easy access to the surface, the last thing you want to worry about is a failure of your scuba regulator, the system that provides air on demand from the aluminum or steel bottle on your back.

However, cold water regulators do fail occasionally by free-flowing, uncontrollably releasing massive amounts of the diver’s precious air supply. When they fail, the second stage regulators, the part held in a scuba diver’s mouth, is often found to be full of ice.

The U.S. Navy uses scuba in polar regions where water temperature is typically -2° C (28° F).  That water temperature is beyond cold; it is frigid. Accordingly, the Navy Experimental Diving Unit developed in 1995 a machine-based regulator testing protocol that most would consider extreme. However, that protocol has reliably reflected field diving experience in both Arctic and Antarctic diving regions, for example, in Ny-Ålesund, Svalbard, or under the Ross Sea ice near McMurdo Station.

There are currently both philosophical and quantitative differences between European standards and the U.S. Navy standard for cold water regulator testing. Regulators submitted for a European CE mark for cold water diving must pass the testing requirements specified in European Normative Standard EN 250 January 2000 and EN 250 Annex A1 of May 2006. In EN 250 the water temperature requirement for cold water testing ranges from 2° C to 4° C. Oftentimes, regulators that pass the EN 250 standard do not even come close to passing U.S. Navy testing.

An iced up, highly modified Sherwood SRB3600 Maximus second stage regulator

The Navy’s primary interest is in avoiding regulator free-flow under polar ice. The breathing effort, which is a focal point of the EN 250 standard, is of lesser importance. For instance, the 1991 Sherwood SRB3600 Maximus regulators long used by the U.S. Antarctic program have been highly modified and “detuned” to prevent free-flows. You cannot buy them off-the-shelf. Detuning means they are not as easy to breathe as stock regulators, but they also don’t lose control of air flow to the diver; at least not very often. Here is a photo of one that did lose control.

NEDU performs a survival test on regulators, and any that pass the harshest test are then tested for ease of breathing. The so-called “freeze-up” evaluation breathes the regulator on a breathing machine with warmed  (74 ±10°F; 23.3 ±5.6°C) and humidified air (simulating a diver’s exhaled breath) at 198 feet sea water (~6 bar) in 29 ± 1°F (-1.7 ± 0.6°C) water. Testing is at a moderately high ventilation rate of 62.5 L/min maintained for 30 minutes. (In my experience a typical dive duration for a dry-suit equipped diver in Antarctica is 30-40 min.)

To represent polar sea water, the test water is salted to a salinity of 35-40 parts per thousand.  The possible development of a “freeze up” of the regulator 2nd stage, indicated by a sustained flow of bubbles from the exhaust port, is determined visually.

In contrast, the European standards call for slightly, but critically, warmer temperatures, and do not specify a duration for testing at an elevated respiratory flow rate. I have watched regulators performing normally under EN 250 test conditions (4° C), but free-flowing in water temperatures approaching 0° C. Those tests were run entirely by a non-U.S. Navy test facility, by non-U.S. personnel, using a U.K. produced breathing machine, with all testing being conducted in a European country. The differences in testing temperatures made a remarkable difference.

Haakon Hop of the Norwegian Polar Institute in Ny-Ålesund, Svalbard.

The NEDU testing results have been validated during field testing by scientific diving professionals under Arctic and Antarctic ice. The same regulators that excel in the NEDU protocol, also excel in the field. Conversely, those that fail NEDU testing fare poorly under the polar ice. For instance, a Norwegian biologist and his team exclusively use Poseidon regulators for their studies of sea life inhabiting the bottom of Arctic ice.  (The hard hat in the photo is to protect cold skulls from jagged ice under the ice-pack.) Poseidon produces some of the few U.S. Navy approved cold-water regulators.

As is usual for a science diver in the U.S. Antarctic Program, a friend of mine had fully redundant regulators for his dive deep under Antarctic ice. He was fully prepared for one to fail. As he experienced both those regulator systems failing within seconds of each other, with massive free-flow, he might have been thinking of the words of Roberto “Bob” Palozzi spoken during an Arctic Diving Workshop run by the Smithsonian Scientific Diving program. Those words were: “It’s better to finish your dive before you finish your gas…”

In both NEDU’s and the Smithsonian’s experience, any regulator can fail under polar ice. However, those which have successfully passed U.S. Navy testing are very unlikely to do so.

 

A previous blog posting on the subject of Antarctic diving may also be of interest.

 

Polar Bear in Town

In some places, the food chain gets down-right personal. In the high Arctic, a careless human is not a top predator; he is a meal. Polar Bears are methodical hunters, showing no fear of humans. When hungry, they are white death on paws.

In 2007 the U.S. Navy and I were helping the Smithsonian Institution Scientific Diving Program teach a course on under-ice diving in Ny-Alesund, Svalbard, an international research town a relatively short distance from the North Pole. Ny-Alesund is the most-northern continuously occupied settlement, and is occupied year-round by scientists and support personnel.

The fjord adjacent to Ny-Alesund is normally covered in 4-5 feet of sea ice in the springtime, making it an ideal location for training in under-ice diving. To gain access to the water, ringed seals travel some distance from land to find holes penetrating the ice, through which they enter and exit the water beneath the ice. And polar bears walk out on the ice to patiently wait for the seals to reappear, and be gobbled up. 

In 2007, the sea ice was gone. The polar bears’ food was not concentrated around breathing holes, and thus the bears were not catching many seals. They were hungry.

By law, the resident and visiting scientists had to carry rifles with them when they ventured away from the icy town to do research in the surrounding hills. But in town, no weapons were required. Polar Bears simply didn’t come into town.

Until one night.

There is only one bar in Ny-Alesund, and it specialized in serving Jesus Drinks during parties. A Jesus Drink is any alcoholic mixture served with glacial ice that is roughly two thousand years old. Get it?

On the night of the bear sighting, a petite Australian doctor friend of mine was walking back from the bar alone, and as she approached the dormitories, she saw a polar bear passing along the side of the dorm I was in. As it disappeared around a corner of the building she was left wondering if she was hallucinating. To make sure of what she saw, she ran across the end of the building just in time to see the white bear reemerge, calmly walking down a snowy road. Since she was close by, I clearly heard her yell the alarm, “Polar Bear in Town!”

The bear was headed towards the area where about a dozen Greenland Huskies, used for pulling sleds, were tied down for the night. So the deathly calm of the Arctic night was shattered by a female doctor yelling at the top of her lungs, while the vulnerable dogs were barking to save their lives — literally.

Of course I hopped out of bed, threw on my multiple layers of Long Johns, slipped into my Arctic parka and gloves and headed out the door to see the bear.

As luck would have it, our experienced dive team leader from the Smithsonian was walking in as I was headed out.

“John, you’re heading outside, in the dark, with a bear close by, and you have no gun.”

“Hmm… I see what you mean.”  I hadn’t looked at it from the perspective of a hungry bear. I turned around and went back to bed.

The next morning we found bear tracks a plenty. The dogs had scared off the bear apparently, since he didn’t claim any animals. Lucky dogs.

Well, the next evening we happened to have a party, with plenty of glowing blue Jesus ice. Although the walk to the bar, down a snowy road with no protection from the elements had not seemed daunting in the fading polar daylight, things were different when I returned to the dorm about midnight, by myself.

There was no moon so the sky was pitch black, but everything else was white, except for me. My parka was brown, and in retrospect made me look a bit like a muffin. And of course I knew that out there in the whiteness, somewhere, was a brazen, hungry bear looking for a snack.

I had never thought of myself as a potential meal, until then.

My head was on a swivel, and my not-yet dark adapted eyes were peering towards the most distant snow and ice, in all directions, looking for a movement that might warn me of a bear. And then the huskies started yelping again, in obvious alarm. That was when I realized that by the time I saw the white on white predator, he would have me. They’re fast, and I had nowhere to run for safety. I was in the open.

That is a curious feeling, knowing that you could be taken like a hunter takes a deer.

I wondered how badly it would hurt.

Well, with that Jesus ice coursing through my veins, I felt safe. That is, I felt safe once I was back in the dorm, snug in my bed.

As I lay there trying to fall asleep, I couldn’t help but reflect on how primal a fear it is, that fear of being eaten.