Posts Tagged ‘hmmh’

How did cities used to sound?

Thursday, March 28th, 2013

by Nick Miller

This is a question that many of us may have wondered about, but we at HMMH together with Professor Karin Bijsterveld of the University of Maastricht, Netherlands, her students, associates and staff of the Amsterdam Museum have provided an answer.  Several years ago I became aware of Karin’s research on urban soundscapes via the internet.  I emailed her suggesting that there might be some synergies between her work on soundscapes and our work creating virtual realities with our Soundscape Builder™.  She initially responded that she didn’t think so, but over the next year, she came up with some possibilities – including demonstrating how cities used to sound.  Eventually I traveled to Maastricht, demonstrated how our Soundscape Builder™ worked, and we both thought we could develop a useful collaboration.

Over the course of the following five years, Karin put together a proposal and was funded to conduct research on sounds significant in earlier eras in Amsterdam, and to assemble an exhibit for the Amsterdam Museum.  Using sounds researched by Karin, Annelies Jacobs, Alexandra Supper and recorded by Arnoud Traa , HMMH mixed, balanced, and conditioned the sounds so that they would be realistic if heard in Dam Square in Amsterdam.

Soundscape Builder for Dam Square 1895

Soundscape Builder for Dam Square 1935


The Sound of Amsterdam exhibit is presented with a touch-screen and headphones.  The headphones provide the realism of binaural recordings, as does the Soundscape Builder™ referenced above.  Visitors can choose the year (1895, 1935 or 2012) and the sounds they want to hear.  The 1895 and 1935 screens provide eleven possible sources and single ones or any combination may be selected; both English and Dutch versions are provided.

The exhibit has had considerable attention with writer Warna Oosterbaan producing an article published in the NRC, a high quality Dutch national newspaper, and Arnoud Traa was interviewed on Radio 1, the most important news radio broadcaster in the Netherlands.

For me, the experience has been delightful, working with new friends, separated by thousands of miles and five time zones, but easily sending files and comments back and forth.  The grand opening to the public is 28 March 2013.

So how did Amsterdam used to sound?  Before predominance of the internal combustion engine – 1895 – the most notable difference for me was the absence of low frequency noise.  But add unmuffled cars and trucks (1935), with back firing and horns, and we become surrounded by a continuous rumbling din.

Having it All

Thursday, July 19th, 2012

by Mary Ellen Eagan

The ongoing culture war about working women has been renewed by an article by Anne-Marie Slaughter (former director of policy planning for the U.S. State Department) in the July Atlantic Magazine, and the announcement this week that the new CEO of Yahoo, Marissa Mayer, is pregnant.  This is a topic (minefield?) I normally avoid:  while I am very proud of the fact that my pregnancy did not sway the HMMH Board of Director’s appointment of me as President of the firm in 2004, I also have dear friends who have chosen to stay home while their kids were infants, toddlers, teens, and even adults.  When people ask (as the often do) how I manage to balance work and home, I tell them there is no such thing as “work-life balance”.  It’s all a scramble, something is always behind schedule, and someone is usually frustrated with me because he or she is not getting enough of my attention – if not at work, then at home.   My favorite pin reminds me.

Working mom pin

However, I also tell them that I am incredibly fortunate to have the choice to attempt this balancing game, as my friends are fortunate to have the choice to stay at home.  I think about the vast majority of women around the world who can’t afford this choice for economic reasons, or some of my male colleagues who don’t feel as though they can afford this choice for cultural reasons.  I think about how fortunate people like Marissa Meyer and Ann-Marie Slaughter – and yes, even Mary Ellen Eagan  – are to be able to have the resources – wonderful spouses, families, and nannies – to support this lifestyle.  It takes a Village. Finally, I think that if people spent less time judging, and more time finding ways to be supportive of the entire range of working families, there’d be real progress in this debate.

INM Version 7.0c and Floatplanes in Alaska

Thursday, January 5th, 2012

by Brad Nicholas

If you have not heard, the Federal Aviation Administration (FAA) just released Version 7.0c of its Integrated Noise Model (INM).  This update is almost entirely about database changes, and a lot of them, including:

  • Updated noise information for nineteen aircraft
    • Nine Airbus jets
    • Six props
    • Four helicopters
  • Sixty-eight changes to aircraft substitutions
    • Twenty-two new
    • Thirty-eight modified
    • Eight deleted
  • Eleven new aircraft
    • Five Cessna jets
    • Four Bell helicopters
    • Two single-engine floatplanes
  • Modified arrival profiles for twenty-one aircraft
    • Sixteen Airbus and Boeing jets (updated reverse thrust segment)
    • Five props (added final landing segment)

There are a few other changes, but you can find those in the release notes.  I’m an instructor for HMMH’s INM Training Course so I take an interest in any new releases, but there was something special about this one.  In the list above, I’m fairly confident that the thing that jumps out at everyone is the floatplanes.  Or maybe that’s just me.  Let’s do a little backstory here.

In June of 2007 I was at Willow Lake, Alaska doing noise measurements for a study of floatplane noise.  Willow Lake is just up the road from the now (in)famous city of Wasilla.  Each year, the frozen lake is used as the restart point for the Iditarod dog sled race.  It’s a scenic little lake, surrounded by forest with houses, cabins, and a community center along the shore.  It is also used by floatplanes.

Floatplane Departure, Willow Lake, AK

 The weather for the measurement program was great and the residents around the lake were friendly and helpful.  Folks in Alaska love their airplanes.  It is by far the most aviation-literate population that I have ever met.  Everyone seemed to be a pilot, have been a pilot, or at the bare minimum, have a pilot in the family.  Given the love of airplanes and the low operations levels (approximately twenty operations per day in-season), why was the study necessary?

In short, the floatplanes, particularly the de Havilland DCH-2, are loud and due to the size of the lake and proximity of the houses to the shore, the planes are quite close to residential locations when they are applying full thrust to get off the water.  Here’s a picture of a Beaver taking off from the deck of residence along the shore.

De Havilland DHC-2 Beaver Take-off, Willow Lake, AK

 At full throttle, that radial piston engine and whirling propeller produced maximum levels averaging 112 dBA at this location for northbound departures.  A single northbound DHC-2 departure per day would give a Day Night Average Sound Level (DNL) of 70 dB.  Actual average levels were quite a bit lower due to a much higher percentage of southbound departures and the fact that the lake is frozen most of the year.  Still, after experiencing this firsthand, I was impressed by the tolerance of the locals.
After the measurement program, it was time to model the average annual conditions for our report.  At that time INM 7.0 was the most current version and the DHC-2 was modeled using the GASEPV, a generic single engine piston aircraft with a variable-pitch propeller.  Unfortunately, that aircraft produced levels that were nine to twenty-three decibels too low compared to the measurements, depending on the location along the flight path.  To put twenty-three decibels in perspective, using that aircraft would be the same as using an accurate aircraft, but modeling one two-hundredths of the correct number of operations.
 After no small amount of work and worry, I ended up creating a user-defined aircraft by modifying the GASEPV to have a much longer take-off distance and increased source noise levels.  This produced a reasonable representation of the Beavers operating on the Lake.
Let’s jump back to 2012 and the release of INM 7.0c.  It has a new aircraft, a DHC-2 floatplane.  Let’s see how it compares on the most common departure path at Willow Lake.  The table below includes measured values and the INM 7.0c computed Sound Exposure Level (SEL) and take-off roll distances for the GASEPV (INM 7.0 representation of the DHC-2), my user-defined aircraft, and the new DHC-2FLT.
Item Description Measured GASEPV User-Defined DHC-2FLT
Site 1 SEL (dBA) near start of takeoff





Site 2 SEL (dBA) take-off “roll”





Site 3 SEL (dBA) just after take-off





Site 4 SEL (dBA) after take-off





Take-off Roll (ft)  





Well, nothing hits the measurements exactly at all points, but the user-defined aircraft and the new DHC-2FLT are clearly better than the old substitution.  Of course the user-defined aircraft was developed from precisely this particular set of measurement data so the agreement is not surprising.  The agreement with the new standard INM data is nice to see though.  The development of this data for the new DHC-2FLT will be detailed in a US DOT Volpe National Transportation Systems Center report which is pending publication (see the INM 7.0c release notes).
The discrepancies for the take-off roll portion are not entirely unexpected.  First, the measurements may slightly overstate the SEL by including some taxi noise.  Second, water is a hard reflective surface and the INM will underestimate the levels when the primary reflected path is off the water due to the inclusion of a soft-ground effect.  You can remove this effect for props in the INM, but it would do that at all sites which would throw off the results at Sites 3 and 4 where the soft-ground assumption is more appropriate.  Third, the measurements were of a limited number of aircraft which performed the majority of the operations on this particular lake.  The general fleet may be slightly different.
So there you have it, INM 7.0c is out and it has two new floatplanes.  This may not matter to most folks, but I can remember a few months back 2007 when this would have made my life a lot easier.

The Deeper Meaning of Rudolph

Thursday, December 22nd, 2011

Rudolph the Red-Nosed Reindeer











I have reached the age where I’m trying to be more reflective and purposeful (aka, midlife crisis).  Or perhaps it’s just that my husband’s deep thinker tendencies are rubbing off on me.  Here’s what he has to say about Rudolph:

  • So.  The family was all together watching Rudolph the Red-Nosed Reindeer last night (Mama in her ‘kerchief and I in my cap).  Our youngest daughter, the seven year old, asked if any of the reindeer were girls.  If you’ve seen the show recently, you might recall that the reindeer pulling Santa’s sleigh all are clearly males: the bucks all have antlers and the does don’t.  However, a quick Google search suggests that that this is actually backwards:  male reindeer typically lose their antlers before December, while the females, which do have antlers, retain theirs. But while the show does get a couple of mere prosaic facts wrong, it’s the mythic aspects of Rudolph I find interesting.

BTW, as further proof, David also pointed out that many of the reindeer names in Clement Moore’s original poem (A Visit from St. Nicholas) while conceivably gender neutral in 2011, were probably quite feminine in mid-nineteenth century America (just think about Dancer, Prancer, Vixen, and Cupid for a start).  This launched a long discussion of whether this 1960s portrayal of Rudolph is actually an anti-feminist screed – don’t forget that Coach Comet shoos Clarice and Mrs. Donner (she’s never named) back to the cave because searching for Rudolph is “men’s work”.  But I digress.  There’s more:

  • Mythic, you ask? Rudolph the Red-Nosed Reindeer?  Well, Rudolph himself is pretty much your basic Joseph Campbell “hero-with-a-thousand-faces”. You’ve seen him before; he’s Luke Skywalker, Harry Potter, all those guys.  However, the other characters are bit more nuanced. Consider King Moonracer.   Who is he and why is he even in RTRNR?  If you don’t recall, King Moonracer is the sovereign of the Island of Misfit Toys.  The misfit toys are in hell and Moonracer is the Lord of the Underworld – he’s the god Hades.  He’s not the Christian devil; he’s not evil.  He presides over those who are unloved and no longer alive.  He also represents the Anti-Santa.  Santa rules Christmastown with mercy and compassion; if you’re good, you get toys (and I’ve noticed, at least in our house, that Santa brings the naughty kids plenty of toys, too).  Hades rules with old-fashioned Old Testament judgment: when Rudolph, Hermey, and Yukon Cornelius ask to stay, Moonracer rejects their request and only allows them to spend a single night on the Island – just enough so they know the taste of being truly forgotten and unloved.


King Moonracer
















Yukon Cornelius






But that’s not end of the story, of course. Rudolph and his friends leave the Island to confront and overcome their fears (though Yukon dies and is raised from the dead – but that’s another story).  Santa sees his own errors of judgment and together Santa and Rudolph redeem the Misfit Toys.  And we hear them exclaim, as they fly out of sight — Happy Christmas to all, and to all a good night.

Up next:  The Grinch

Nails on a Chalkboard

Friday, November 11th, 2011

by Mary Ellen Eagan

I had an “NPR moment” the other day, but it was not the kind they advertise on pledge drives.  This story about Why Nails on a Chalkboard Drive Us Crazy had me sticking my fingers in my ears in a way I hadn’t since high school.  Not good when you’re driving (so I’ll caution you, too, before you click through to be sure you have hands free).

The team of German and Austrian researchers, Michael Öhler of the Macromedia University for Media and Communication in Cologne and Christoph Reuter from the University of Vienna, first picked out two sounds they determined were the most annoying to people: scratching fingernails on a chalkboard and squealing chalk on a slate.  They then played the sounds to a group of volunteers, half of whom were told their real origin and the other half who believed they came from contemporary music.  The researchers found that people who believed the sounds were art rated them as less grating than those who knew where they really came from, suggesting a psychological component to people’s annoyance.

But they also found that the research subjects had clear physiological reactions to the noises, such as increased heart rate, sweating and blood pressure regardless of their beliefs of the sounds’ origin.  This is apparently the consequence of the frequency of the sounds, between 2,000 and 4,000 hertz, which hits the frequency range over which the human ear is considered to be most sensitive because of the anatomy of the ear canal, the scientists said.

I’m blogging about it because it makes two points that are relevant to human reaction to transportation noise:  frequency and attitude.

  1. First, transportation noise also happens to have most of its acoustic energy in the same mid-frequency range (also babies crying – see my previous post on that issue).
  2. Second, attitude plays a significant role in our response (annoyance) to sound (noise).  The chalkboard research showed that when subjects were told before listening to it that the recording was “modern music”, they were much more tolerant than when they were told they’d be hearing nails on a chalkboard.  We often joke about people being much more tolerant of “the sound of Freedom” near military bases, but there is good reason.   Sandy Fidell has written extensively that a significant portion of the variance in annoyance dose-response curves (comparing aircraft noise exposure doses to levels of high annoyance) can be attributed to attitude toward the noise source.  Airports that take this to heart, and make concerted efforts at public outreach, can attest to the difference that attitude makes.

Fortunately, in the case of both chalkboards and aircraft noise, technology has evolved significantly in the last 30 years, so that the need to stick our fingers in our ears is much less.