Why Your Conference Room Technology May Soon Be Obsolete: Part II
As the VGA connector continues its rapid transition towards obsolescence (referred to in Part I of this post) many people simply assume that using adapters (such as HDMI to VGA) will solve the digital-to-analog connectivity problem. While this may work in the short term, it ignores the looming problem of DRM (Digital Rights Management), a way of encrypting new media to protect against copyright infringement. DRM uses something called HDCP (High Bandwidth Digital Content Protection) to control which devices are allowed to receive the video signal. So how will you know if you’re using digitally protected content? Well, for starters, your adapter will just stop working. (more)
Why Techies Buy Audio-Video Gear Online
My church recently decided to upgrade from our old analog mixing board to a brand new digital mixing console. The interesting part of this process was that they did not buy it through a local AV contractor. They purchased the sound board online through a company that specializes in phone and internet box sales. This got me thinking about the trend over the past few years in which more and more Audio Visual end-users purchase equipment from online sources instead of the local dealer or shop. Is this a good thing or a bad thing? And why is this becoming the norm? (more)
The Speaker Shootout at High Noon
Question: How do you assure your client that they are getting the best possible speakers for their Auditorium or Fine Arts Center? Answer: You hold a “speaker shootout”. Recently one of our clients was in this exact situation, so we did just that. We invited several manufacturers of line array speakers to show up, all on the same day, so we could let our client hear the differences in sound quality back and forth in the exact same auditorium they would be installed in. Three different manufacturers arrived, speakers in tow, to hang their line arrays for the shootout. As the client’s AV Consulting Firm, we were there to moderate the shootout and ensure that each manufacturer got a fair shake (clean signal, volume levels, sound power levels, and so on). And then we began. The client had arranged for a group of about 20 listeners and key decision makers to join us for the shootout as a virtual “jury” to help decide which speakers to purchase. May the best speakers win! (more)
Why Your Conference Room Technology May Soon Be Obsolete
You can’t get away from the digital age. It seems like digital technology is everywhere. As Audio-Video designers, the march towards all things digital is having an impact on display technologies as well. Meanwhile, flying under the radar, there is a subtle shift happening in how the average person shows information from a computer onto a projector or display. (more)
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)
The Leaky Bucket | How Sound Escapes
Blocking sound is often analogized to plugging the holes in a leaky bucket. If you plug up all the bucket holes except one, the bucket is still going to drain. In acoustics, an outstanding partition design will not adequately block sound if holes and weak spots exist where sound can find its way through. (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.
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)
Binaural Recording with a Dummy Head
This past week, as we took acoustical measurements at the Calvin College Fine Arts Center in Grand Rapids, Michigan, a music teacher poked her head into the auditorium and asked if aliens had landed. “Well, not exactly”, I said. But I admitted that it did look and sound a lot like it. Binaural “dummy head” recording isn’t exactly something you see (or hear) everyday, so here is a brief glance at why this technique is used by acousticians. (more)
The Secret Lives of IMAX Theatre Designers
Ask typical movie goers for the definition of an IMAX Theatre, and they will likely give you an unclear response about a big screen and loud sound. On these points they would be right – but only as a vague definition. You see, the IMAX Corporation has gone to great lengths to make sure that every IMAX-certified theatre actually delivers what they consider to be “The IMAX Experience ®.” They want to make sure that the IMAX brand truly means something to consumers – something more than “a big screen and loud sound.” And if that IMAX brand is to mean anything, then every IMAX Theatre must deliver the same high quality movie experience from Los Angeles to New York to your hometown, and so on. This is achieved through the process of IMAX certification, which involves enforcing stringent specifications in two realms: film production and theater design. (more)
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