Bose Vs-1
2010
|
|
Koss Pro4AAT Titanium Pro Headphones $62.00 Koss Pro4AAT Titanium Pro Headphones are rugged, closed-ear headphones built tough enough for broadcast use but at a price even the smallest studios can afford. Built for extreme durability and with a closed ear design for maximum bass and isolation, these headphones have a wide frequency response of 10 Hz-25 kHz and feature titanium-coated high polymer diaphragms for crisp, accurate sound and oxy… |
|
|
Koss KEB4 Portable Earbud (Black) $0.99 Koss KEB4 Portable Earbuds are ultra-lightweight stereophones that fit perfectly into anyone’s price range or travel plans. A see-through, wind-up case is provided for storage and protection. The 4-foot straight cord also has an L-plug that is designed for active use. The dynamic element has a frequency response of 70-20,000Hz…. |
|
|
Bose VS-1 Video Expander – Video signal converter – black The Lifestyle® VS-1 video expander brings the simplicity and elegance of Lifestyle® system audio to your attached video components.The Lifestyle® VS-1 has been designed exclusively for use with Lifestyle® systems, and simplifies both system setup and operation. The Lifestyle® VS-1 includes: Integrated system design â works seamlessly with Lifestyle® 48, 38, 28 Series II and 18 Series II D… |
Basics of active noise cancellation and how it differs from passive treatment
Observations of an industry insider ANC 1 of 3
Active Noise Cancellation in relation to passive noise cancellation
Whenever I wonder what I do in a social context that I brace myself for a lot of blank stares. In the beginning, I would answer with a very frank, "We produce active systems of noise reduction for heavy industry." It has always been followed by a long silence a few brave said: "So you insulation? or something to that effect. To put the individual, when confronted with words Cancellation Active Noise, all they hear is noise, and they fall back on their experience to help categorize what I do, it usually means insulation.
In recent years, active noise cancellation has become more common place and understood by the outstanding efforts of Bose and other active in the production of ear protection. There is still a significant amount of confusion if the exact nature of active noise cancellation (ANC) and how it is different passive noise suppression products such as insulation. The purpose of this paper is to try to describe these differences in a manner that is both accessible and understandable to all.
Basics
In other words, the passive noise cancellation processing are all about deflection and absorption. They are, in essence, a barrier between the observer and the source of noise. Passive treatments take the form foam plugs in the ear, foam lining between the engine of a car and the interior and even the walls 20 feet of concrete barrier the busy streets. Their sole purpose is to absorb the sound and turn it into something else (usually heat), or take into account in another direction.
Active noise cancellation, on the other based on the principle of destructive interference, the idea use a wave to cancel another wave. The easiest way to visualize this principle is to use waves in the water. If I drop a pebble in a pond it creates ripples (waves). By dropping a pebble in the pond second shortly after the first, mix rock like the undulations of each, small areas are created where there are no visible waves. In fact, these points of the surface is perfectly smooth. This is a product of the destructive interference.
Another way to visualize it is by imagining a wave. Each wave has two fundamental properties: in how fast it goes up and down (frequency) and how far it goes up and down (pitch). Also, remember that a full wave peaks and valleys. Now imagine adding a second wave to the first. This second wave is identical in frequency and amplitude, but the second wave is out of step with the first. So much so that the peaks and valleys of the second wave line exactly with the peaks and valleys, respectively, of the original sound wave. When sound waves are identical combined, they add their energy. Let's say the first wave at its peak has an energy of 1, and the second wave of its Valley has an energy of -1. Added two causes combined energy equal to zero!
Why Instead of using Active Passive
If this explanation seemed very complicated, do not worry, it is. The implementation of active noise cancellation is still more complicated than described. So why bother with all this? Because there are certain waves that passive treatments are not able to stop. A colleague of mine likes to say "With sufficiently concrete and re-bar, everything can be quiet." Unfortunately, there are many applications where concrete and rebar are not an option.
Take for example your home. Usually, doors and windows closed, you do not hear the birds singing, or drive through typical auto. But even with everything closed, you can still hear that car with the thumping bass as he drives by. The reason is that the low-frequency noise can penetrate physical barriers more effectively than high frequency noise. It is the same principle that lets you get an AM radio station while driving in the hills where you can not have an FM station in all the waves here. are much lowest frequency and is not affected as much by physical barriers.
That being said, passive treatments have a practical threshold less how much they offer little or no reduction. The lower limit is questionable, but for the most part, passive treatments began to suffer reduce efficiency to about 1000 Hz, and their performance will degrade as the frequencies are lower. active noise cancellation works best on noise below 300 Hz is possible to use the ANC on the noise up to 500 Hz, but the reductions are limited and must be considered on a case by case basis. (For more information on why ANC is useful only up to 500 Hz, please read Part 2 of this series.) As you can imagine, with different areas of effectiveness, the two methods for reducing noise are in fact complementary to another. Active noise cancellation should not be considered as a replacement for the passive treatment. In fact, we often recommend to our clients that their first do everything they can with passive noise cancellation, and if the noise levels are still too much of a problem, then consider the active cancellation of noise.
Conclusion
Although active noise cancellation is a high tech solution for unwanted noise. This is not a substitute for a good piece of high density foam. Because of costs associated with each system, we recommend that you do everything possible with passive forms of treatment, then re-evaluate your environment before deciding on the implementation of active noise cancellation.
About the Author
Taylor Reynolds is the Director of New Business Development of NVH Technologies (http://www.nvhtechnologies.com) Having worked for a number of years in the active noise cancellation industry, Taylor is used to working with individuals with an extensive background in acoustics as well as those with almost no understanding of acoustics. The purpose of this article is to help educate those individuals trying to understand active noise cancellation better.
2006 Mazda MAZDASPEED6 in Roswell Atlanta, GA 30076 – SOLD
|
|
Koss Pro4AAT Titanium Pro Headphones $62.00 MODEL- PRO4AAT VENDOR- KOSS FEATURES- Pro4aa Titanium Headphones Home headphone is a headphone that is primarily used in the home, with home electronics. Generally speaking, home headphones are somewhat larger and more isolating. Home headphones with cords tend to have a longer cord.* Titanium coated high polymer diaphragm for accurate sound reproduct… |
|
|
Koss KEB4 Portable Earbud (Black) $0.99 Koss KEB4BK Earbud Stereophone is ultra-lightweight, the perfect accessory for portable and replacement users. The KEB4 includes a see-through, compact, wind-up spool carrying case for easy storage and protection when not in use.A 4-foot straight cord and L plug provide flexibility and reliability for active use. The KEB4 is the perfect travel companion designed to fit into anyone’s price range or… |
|
|
Bose VS-1 Video Expander – Video signal converter – black The Lifestyle® VS-1 video expander brings the simplicity and elegance of Lifestyle® system audio to your attached video components.The Lifestyle® VS-1 has been designed exclusively for use with Lifestyle® systems, and simplifies both system setup and operation. The Lifestyle® VS-1 includes: Integrated system design â works seamlessly with Lifestyle® 48, 38, 28 Series II and 18 Series II D… |
http://www.millionaireprofitsecretsplus.com http://www.theassassinationassessed.com http://www.trafficsiphonplus.com
Comment