Posts Tagged ‘acoustics’

Of Noise and Nature

Thursday, December 22nd, 2016

By Nick P. Miller

I wonder how many people experience the sense of peace and uninterrupted reflection that comes from the “quiet” of nature, unaffected by human sounds.  I know I was aware of how special it seemed when I was vacationing as a kid with my family on Lake Champlain and walked to the shore in the evening.  I heard only rippling of the water – nothing else.  Every time I’m in a place of such quiet, whether a National Park or early Sunday morning at home, I’m awed.

We’re usually not much aware of the sounds around us; so many are worth ignoring.  I think you need an attentive awareness of what you can hear to really register the effect of quiet.  However, if we pause and listen for a minute or two, the multiplicity of sounds may be surprising, especially in a city.  In fact, that’s the only time most people notice the sounds that they can hear – when they stop and reflect.  For most of the time, we tune out and don’t consciously hear the sounds that are irrelevant to us.

There is some science that shows how the audible and visual features of a place interact to convey an impression.  Forty-four subjects were instructed to judge the tranquility of audio / video presentations of 11 relatively “tranquil” locations on a scale of 0 (not at all) to 10 (very much), and that they should judge a tranquil environment as one that they considered a quiet, peaceful and attractive place to be.  The figure below shows the results.   Except for Otley Market and Building Site, the locations are primarily natural.  The combined audio and video presentation ratings show not only the interaction of the two, but that together the resulting tranquility rating is not necessarily an average of the two separate responses.  Broadly speaking, the audio for these 11 locations tends to either support the visual sense of tranquility or reduce it.  That is to say, a place can appear very tranquil, but the sounds can ruin that sense.  This degradation by incongruous sounds is more significant the more natural and beautiful is the visual.

Other studies have demonstrated that locations with natural sounds and landscapes can be restorative and that spending time there will actually clear your mind.  People’s problem solving is improved after spending time in a setting that is predominantly natural.

Unfortunately, it is becoming more and more difficult to find places dominated by natural sounds.  The things we want (thanks for the idea Garret) – cars, planes, various recreational vehicles, leaf blowers – are so ubiquitous that it’s hard to get away from their noise. Even in natural areas you’d expect to be very quiet, it’s possible to hear a chain saw or small plane miles away.  Most ubiquitous are high-altitude jets; at six miles high, they can be as much as 20 dB louder than quiet natural settings; 20 dB louder is a lot – an intruding sound you couldn’t ignore.  And consider that the most beautiful natural places are the ones that most easily lose the sense of solitude and tranquility they convey when human sounds intrude.

I admit real quiet can be spooky for some.  If you’re a city person, enamored of the hustle and bustle, then maybe serious quiet might be unsettling.  But I have found, and I think most people will, that time spent in nature with little other than natural sounds can be a wonderful, memorable experience, later pleasantly recalled.

HMMH Assists FAA and Airports in Standardizing the Process for Determining Sound Insulation Program Eligibility

Tuesday, June 7th, 2016

by J. Eric Cox

HMMH has provided acoustical testing, design, and other consulting services to airports throughout the country that have implemented sound insulation programs in accordance with FAA Order 5100.38D Airport Improvement Program (AIP) Handbook. HMMH has most recently been conducting sound insulation measurements around several airports including:

  • T. F. Green State Airport (PVD) in Providence, Rhode Island
  • Tweed – New Haven Airport (HVN) in New Haven, Connecticut
  • Louisville International Airport (SDF) in Louisville, Kentucky (shown below)

OLYMPUS DIGITAL CAMERA

OLYMPUS DIGITAL CAMERA
Over the last several months, HMMH has also assisted the Federal Aviation Administration (FAA) and airport sponsors in standardizing the process for determining sound insulation program eligibility per current FAA requirements and criteria, which include that the average interior noise level for a residential building or educational facility must be 45 dB or greater.This work has included a recently completed Policy, Engineering, Analysis and Research Support (PEARS) study for the FAA Office of Environment and Energy regarding selection of appropriate aircraft noise spectra for use in determining outdoor-to-indoor building noise level reduction (NLR).

In addition, we have assisted several airport authorities (including Los Angeles World Airports and the Port of Seattle) in developing sound insulation program acoustical testing plans (ATP) for FAA review. This work has included providing additional information and supporting details related to the various methods that may be used to measure the exterior building façade sound level in the determination of NLR, each of which require a different adjustment to the measured level to account for the reflection of sound energy from the façade under test that is not transmitted through the exterior wall and instead travels back to the measurement microphone.

And as part of our on-going sound insulation testing work at Louisville International Airport, we have recently been evaluating noise mitigation program eligibility for several educational buildings and residential dormitories at the nearby University of Louisville Belknap Campus. This has required us to evaluate methods to compute daytime average sound levels (as required for educational facilities by FAA) that are consistent with the noise study, aircraft operations data, and analysis methods previously utilized to generate the Day-Night Average Sound Level (DNL) noise contours for the Noise Exposure Map (NEM).

Finally, I will be presenting a paper at the New England Noise-Con Revolution in Noise Control conference to be held in Providence, Rhode Island during June 13 – 15, 2016. This paper investigates the correlation between aircraft interior noise levels and various residential building construction features. The results of this analysis are then considered in the context of the current guidance provided in Appendix R of the FAA AIP handbook, which specifics a procedure to determine the eligibility of residences for sound insulation programs based on interior noise levels for categories of homes. Ultimately, we were unable to identify any specific building construction details which might result in truly effective categorizations of residential structures for this purpose since even the best possible approaches resulted in ranges of interior DNL noise levels that directly overlap and all of which span the 45 dB FAA criteria. An example presentation graphic is provided below comparing average interior DNL values for single family homes with total window assembly glazing thickness.

graph
If you are interested and would like to learn more, please attend my Noise-Con presentation entitled “Investigation of Correlation between Aircraft Interior Noise Levels and Residential Building Construction Details” on Tuesday June 14, 2016 from 1:20 PM – 1:40 PM in Room 550 A/B of the Omni Providence Hotel during the “Building Acoustics Measurement and Modeling” conference session. Hope to see you there!

 

 

Some Stuff I Like to Think I’ve Learned

Thursday, April 21st, 2016

by Nick Miller

founders 2a

HMMH Founders (from left to right) Nick Miller, Andy Harris, Carl Hanson, and Bob Miller.

I began my career in acoustics, noise, and how people react to noise in 1973 after quitting the Air Force. Not that USAF was a bad experience – it taught me a lot.  After living with pretty liberal parents, and going to liberal universities and colleges for about 8 ½ years, I found I actually could like politically conservative people and shoot an S&W Combat Masterpiece with reasonable precision without really aiming.  But never mind that; it’s just that lessons for life are everywhere.

Anyway, I began at Bolt Beranek and Newman in Cambridge Mass, (BBN) and found myself in a liberal, open-minded organization where my group in environmental noise analysis and control was struggling to find the best ways to resolve or attempt to resolve the relatively new political issue of the public’s dislike of all sorts of noise – from factories to construction to race tracks to new parking garages to planes, trains and automobiles. We worked with and for the likes of Ted Schultz, Ken Eldred, Dick Bolt (testimony about the 18 minute gap in the Nixon tapes fame), Bob Newman, and other brilliant people of whom you may not have heard like Chuck Dietrich, John Shadley, Warren Blazier and other good guys.  Truly a great place to start a career and learn.

As BBN turned away from acoustics to computer workings like design of the internet, Andy, Bob, Carl and I founded HMMH in 1981 (guess what the initials stand for). It was, and continues to be, another great experience, if you can get past the initial stress of putting your house up as collateral.  I remember vividly the day we four with our spouses met with bank representatives and all signed papers tying the future of our homes to our future success (or failure).  Well, we actually succeeded beyond our dreams, had a heck of a good time working together, bringing compatriots in noise into the company, sharing ups and downs, and building a company of more than 40 people.  That may not seem large to most people, but for a boutique business, we thought – “Not bad.”

Andy was president until 1989, and then I was until 2004 when we handed leadership to Mary Ellen. Andy, Bob and Carl have all retired and I will be within a year’s time.  I’ve naturally started wondering what to do next, and what about my 40 plus years of experience?  Do I walk away and leave the battle field of political acoustics or not?  I’m leaning toward going cold turkey.  However, my son-in-law’s father pointed out how much experience, ideas and insights I would be taking away from the industry.

To get to the point, I have decided to at least write a series of blogs describing some of the things I’ve learned about noise and people, leadership and mentoring. This is perhaps a common human desire to pass on something of what one has learned in a lifetime career.  I’ve noticed that a number of old folks like to write books about their accomplishments.  I certainly won’t be doing that.  I’m not sure what I’ve accomplished, but I do know I’ve learned some things.  Also these things are not worth a book; I’m not going to do what I notice some authors do and take a few basic pieces of wisdom and use up 200 to 300 pages talking about them in different ways.

So, I intend to write a series of blogs over the next months. That is my intent, anyway.  I will start with issues of the discipline: noise and people’s reactions thereto in different contexts and to different sources.  This will be fun for me, anyway.

In Memoriam

Monday, October 28th, 2013

by Mary Ellen Eagan

Laymon Miller

Laymon Miller

 

 

 

 

 

 

 

 

 

Many of us at HMMH knew Laymon Miller personally – he was an important early contributor to the practice of noise control.  Laymon did much of the early work on aviation and highway noise control, as well as industrial acoustics, as described in this biography prepared for a University of Texas award that Laymon received:

Laymon Miller, Leo Beranek and Walden Clark of BBN in Seattle with Boeing 707 in background

Laymon Miller, Leo Beranek and Walden Clark of BBN in Seattle with Boeing 707 in background

 

 

 

 

 

 

 

 

 

 

 

 

Most of Laymon’s consulting work was: (1) Noise and vibration control for HVAC (Heating, Ventilating, and Air-Conditioning) systems in buildings; (2) noise control for manufacturing plants, aimed at meeting OSHA noise regulations for the protection of workers’ hearing; (3) noise surveys and noise control aimed at protection of communities against the intrusion of excess noise from manufacturing plants, highways, power plants, airports, etc.; (4) noise and vibration control of products for customer acceptance; and (5) vibration isolation designs for achieving very low vibration levels for particular instruments or processes.

From my perspective, one of Laymon’s greatest contributions – not only to the field of acoustics, but also to the world – is Bob Miller, one of HMMH’s founders and former Chairman of the Board.   Bob mirrors not just Laymon’s passion for acoustics, but his courtesy and grace, and is a constant reminder that scientific inquiry and curiosity are a wonder.

Laymon will be missed, and our thoughts and prayers go to Bob and his family.

Founder’s Award

Monday, October 28th, 2013

by Nick Miller

At last week’s HMMH Annual Stockholder Meeting, the Founders of HMMH presented their award for excellence “In recognition of outstanding performance on a project that was uniquely challenging, technically innovative, and resulted in proven client satisfaction.”  The award was given to the project “On-Board Sound Intensity Measurements to Evaluate the Noise Reduction of Pavement Grinding, I-195, Providence RI.”  The Project Manager was J. Eric Cox, Principal in Charge was Christopher W. Menge, and the team included James E. Ferguson III, and Ryan Cranfill.

From left: Carl Hanson, Chris Menge, J. Eric Cox, Nick Miller

From left: Carl Hanson, Chris Menge, J. Eric Cox, Nick Miller

 

 

 

 

 

 

 

 

 

 

 

The purpose of the project was to prove that adequate sound reduction of I-195 road noise had been achieved by diamond grinding of the concrete bridge deck, mainline roadway, and on/off/interchange ramp surfaces. Grinding operations were conducted to reduce noise generated by traffic traveling over transverse tining. The “OBSI” measurements had to be made on 19 ramps and roadway sections, in the wee morning hours when little other traffic was using the roadways.  Client David Freeman of Maguire Group, Providence, RI said that “it worked out really well and the results [of the measurements] were used to justify a bonus to the contractor.”

More information on OBSI can  be found on HMMH’s website: http://www.hmmh.com/on-board-sound-intensity.html.