Introduction
The history of noise cancellation dates back to the time in the 1950s when technological innovations enabled the engineers to invent the system mechanisms to cancel the noise that originated from the helicopter and the airplane cockpits, Dr. Bose is a very notable personality in the history of noise-canceling headphones, he began his after being provided with headphones while on his international flight, he was dissatisfied with the poor quality which could not withstand the loud engine noise. He began to work on the headphones to find effective means of improving the quality which took him almost a decade of research (Federico, Eric & Nauta, 95).
Initially, the noise-canceling technology was meant to protect the pilots from noise interferences especially those that were participating in the first non-stop flights around the world. The noise-canceling headphones that are available on the market use Analog technology, however, there are other standard methods where digital processing is applied in active noise and vibration control, in particular, noise-canceling is very effective in countering the airplane engine noise, in this case, the headphones have the same size as the normal headphones. However, the actual electronic circuitry is located in the plane’s hand rest where it takes the sound signal from the microphone which is behind the headphones then inverts it sums it up together with the audio signal (Berger, 23)
Mode of working for the noise-canceling headphones
The noise cancellation in the headphones is achieved mechanisms that aim at reducing the unwanted ambient sounds, also referred to as the acoustic noise; the reduction applies the active noise control. Effective noise cancellation ensures that the sound signal is delivered even at very low volumes. This allows for comfort in communication even in noisy situations such as in the airliner.
The noise-canceling headphones in most cases make use of the Active Noise Cancelling technique to cancel the low-frequency portions of the noise; however, this technique relies on the more traditional methods such as the soundproofing method in the prevention of the higher frequency noise from reaching into the ears (Seabridge & Morgan, 202). This technique is preferred because of the numerous advantages that it provides; it’s cheap, it has a simplified circuit which reduces the demand for the complicated circuit especially at higher frequencies the active noise cancellation i8s is not effective. It is worth noting that during high frequency to cancel external sources of noise is attained by using a sensor which when combined with the emitters of wavelengths that cancel noise (Hansen 58).
Active Noise Cancellation (ANC)
This is a technique that involves the use of one or more microphones that are placed near the ear. There is a sophisticated electronic circuit that makes use of the signal from the microphone in the generation of the anti-noise signal to counter the effects of the noise signal. With the production of the anti-noise signal from the speaker drivers of the headphone, the ambient noise is canceled by the destructive interference, this results in a clear sound signal being delivered to the ear (Seabridge & Morgan 81).
Principle of working of ANC
Sound is a pressure wave that is made up of two phases; the compression and rarefaction phases. The noise-cancellation speakers produce the sound wave signal which has an equal amplitude but it is in anti-phase as compared to the noise signal.
According to Benesty Et al 213 noise cancellation can also be achieved through the use of the principle of attenuation, in this case, the noise cancellation speakers are located at the same location as the sound source to attenuate the two signals, under these conditions it is required that the noise cancellation speakers are maintained at the same audio power level as compared to the noise source, another technique makes use of the transducer which functions by emitting the cancellation signal, the transducer may be strategically located at the position where the sound attenuation is needed (Hansen 34).
This technique is advantageous since it consumes less power, However, it is disadvantageous since it is only effective with a single attenuation point, the noise cancellation at multiple points is not possible due to the high chances of matching of the unwanted sound and the cancellation signal due to the three-dimensional nature of the sound wave thereby creating the alternative zones with both constructive and destructive interferences (Benesty et al, 197)
Modern technological advancements have enabled the use of the digital computer as a form of advanced active noise control, the computer receives and analyzes the noise signal, and it then generates the inverted signal which cancels the noise signal through destructive interference. Hansen 87 explained that the Active Noise Control techniques differ from the passive Noise control techniques because the former techniques are powered while the later techniques are at unpowered levels. Soundproofing is a form of passive noise control which is achieved through the use of techniques such as insulation walls or sound-absorbing ceilings. The Active Noise Control is advantageous because it is less bulky, more effective at low frequencies, and blocks the noise selectively.
Conclusion
It is worth noting that the technology aimed at curbing noise in headsets has taken advantage of various methods of technological innovation. The mechanisms are used to cancel out noise from headsets. Currently, there are various applications used to curb noise that could be otherwise destructive to man’s ears. For instance, it has played a major role in helping individuals working in cities deemed to be very busy characterized by a noisy environment.
There is already a version of the low-tech solutions to this problem, this include; the Ear-plugs and the sound dampeners which are available, however, this are not efficient. The mechanism to cancel noise attains its objective as it blocks sounds from their origin rather than blocking the same from getting their way to the human hearing system.
The innovation of canceling noise in headsets uses dimension 1 zone. Apart from the noise-canceling headphones, there have been other commercial applications that have succeeded, this include; the active mufflers, and the control of noise in the air conditioning ducts (Seabridge & Morgan 72). It is also important to note that the technology to cancel noise has played a major role in helping cut down the amount of noise that interferes with a worker at a place of work. Finally, the cyclic attribute of engines ensures that examination of signals as well as canceling noise is possible and easy.
Works Cited
Benesty, Jacob, Chen, Jingdong. Huang, Yiteng. & Cohen, Israel. Noise Reduction in Speech Processing, New York: Springer, 2009. Print.
Berger, Elliott. (Ed) The noise manual, AIHA, 2003. Print.
Federico, Klumperink, Eric & Nauta, Bram. Wideband low noise amplifiers exploiting thermal noise cancellation, New York: Springer, 2005. Print.
Hansen, Colin. Understanding active noise cancellation, New York: Routledge, 2001. Print.
Seabridge Allan., & Morgan, Shirley. Air Travel and Health: A Systems Perspective, New York: John Wiley and Sons, 2010. Print.