If It Sounds Like Noise to You, It May Be “Esion”
Fundamentally, sound is “that which we hear”. What we hear at any given time can greatly influence us. We use sound to communicate, to express warning, fear, pleasure and excitement. Some sounds can relax us and help us fall asleep, while other sounds can distract us and make it more difficult to perform simple tasks. Different sounds can be soothing and pleasing or annoying and irritating. Accordingly, determining “What is sound?” and “What is noise?” can become a highly subjective task. As engineers and scientists, it’s our job to generate generalized models that have a high level of correlation to humans (or to specific populations). (more)
When One Size Does Not Fit All | Diffuser Sound Levels
On a recent trip to India, I discovered a cute clothing sizing term called “free size” which is equivalent to “one size fits all”. Free size clothing must be a manufacturer’s delight since production and distribution are greatly simplified. Adjustments to the size of the garment are typically made through waist ties of various designs and if needed, permanent alterations.
In the A/E/C industry, diffuser, grille and register (air device) manufacturers have chosen the free size philosophy when it comes to providing sound data. (more)
Elbows vs. Sound Attenuators: Interchangeable?
It is common belief that a series of elbows near an air handling unit (AHU) can accomplish the same insertion loss as a manufactured duct sound attenuator. It’s true that elbows are less expensive than sound attenuators, but what acoustical performance is really achieved with this “low cost” substitution?
Let’s compare the two designs. Using the tables presented in the 2007 ASHRAE Handbook – HVAC Applications, for any type of elbow (round, rectangular, acoustically lined or not), the width of an elbow (in the plane that it turns) must equal or exceed 30 inches to get ANY insertion loss at 63 Hz. A 30 inch wide elbow provides only 1 dB of insertion loss (IL) at 125 Hz . These two frequencies are typically of concern when reducing sound from AHUs.
2009 AIA Grand Valley Honor Award Winners
This past Saturday night we attended the 2009 AIA Grand Valley Honor Awards program at the Urban Institute of Contemporary Arts (UICA) in downtown Grand Rapids. As a Professional Affiliate Member of the AIA, our firm serves as consultants to architects. Although we are not eligible to receive an award, we look forward to the chance to support our friends and celebrate their accomplishments in architecture over the last year. In addition, Acoustics By Design was pleased to be the acoustical and audio/video design consultants for six of the nominated projects! The real surprise of the night was that the independent judges panel, made up of three distinguished architects from Iowa, declined to give out awards in several categories. (more)
Rooftop Roulette | Noise and Vibration Isolation for Air Handlers and Mechanical Units
Over the years as an acoustical consultant I’ve seen a lot of architectural firms locate rooftop air handling units over or near acoustically sensitive spaces; then they put up resistance to doing the necessary extensive noise controls that are needed for such a situation. The protest usually includes “but we’ve never had to do that in the past…” I call this rooftop roulette, because while not incorporating noise control design may have worked in the past, it does not guarantee future success. (more)
It’s time for another semester, and I tell my architecture students that if there’s one thing they learn in my acoustics class, it’s that porous absorbers do not block sound. A porous sound absorber, by definition, has many tiny interconnected voids that sound travels through. Fiberglass and open cell foam are examples. The sound wave loses its energy through friction between the air particles and the fibers/void walls of the material it is passing through. (more)
As long as you haven’t been living in a cave this past year, you’ve probably noticed that America’s new favorite color is green. Even the “big, scary corporations,” like Walmart and McDonalds, have re-worked their ad campaigns to reflect a more-green, environmentally friendly corporate image. Seemingly everyone is going green. The term “greenwashing” has come to describe businesses that project a green corporate image (through ad campaigns, marketing, and so on) but take little action to reduce their own carbon footprint or energy consumption. They are “green” in name only. At the same time, some organizations are embracing a new paradigm of green business practices and sustainability. So, who’s really “green” and who’s just “greenwashing?” (more)
Noise Isolation for Mixed-Use Developments
In the world of architecture, we frequently hear the term “mixed-use development,” and our firm is increasingly called upon to provide mixed-use development acoustical consulting. The term “mixed-use” generally refers to a development that incorporates residential and commercial space in a close-knit fashion. Mixed-use developments have been constructed for centuries, often taking the form of residential space above retail space – such as the shopkeeper living above the shop. As industrialization increased, mixed-use fell out of favor, and segregated land-use became popular. But late in the past century, mixed-use developments resurfaced, often with the intent of revitalizing urban areas and creating walk-able communities – as opposed to communities where a person must drive a car or take some form of public transportation to perform their daily routine. (more)
This past spring I was blessed to be married to an amazing woman who thankfully doesn’t mind when I walk into a business and point out the acoustical flaws and potential improvements that could be made “if they had only hired an acoustical consultant!”
During our engagement, the task of planning for the wedding began, and of course, we visited venues for potential places to hold the reception. In the months leading up to the big day, we attended several weddings and receptions and were on the prowl for good ideas as our wedding neared. (more)
Subscribe via email
Enter your email address
Delivered
by FeedBurner