Friday, May 6, 2011

How Do Deaf Aids Work?

By Owen Jones


Hearing aids in the strictest use of the term have been around for ever. When early man shouted a greeting or a threat from a long way, the listener in all probability cupped his hands behind his ears in order to better hear what was being said to him. In general, people did not live a long time before several hundred years ago, especially the poor and the very rich, so being hard of hearing was not the problem that it is today.

People were either born deaf or went deaf through illness. People did not go deaf through being old or through industrial noise because there were no machines. The poor died of hard work and sickness and the rich were assassinated. Scholars and monks were possibly the only classes that lived into old age and scholars were often monks and visa-versa. These people were certainly clever enough to have developed the hearing trumpet from the cupped hand.

But that is all that mankind had for thousands and thousands of years. More of the sound (or vibrating air) was caught by the cupped hand or trumpet (thereby enlarging the outer ear) and forced into the inner ear. Then, all of a sudden in historical terminology, along came electricity and wiring and circuitry and batteries not much more than a hundred years ago.

Modern hearing aids work on much the same principle. A microphone collects the sound, amplifies it and instantaneously plays it back through a loudspeaker which is placed in or behind the ear. Owing to the level of technology, the early hearing aids were big and unsightly. The battery was the size of a house brick and so was the amplifier. The microphone was large and the speakers were headphones. There was a little volume control, but on the whole, you got what it gave you.

These days hearing devices still work on the same principal, but micro technology has permitted manufacturers to miniaturize the set-up so that all the components fit in one small device, which is then put in or behind the ear. Most of these hearing aids can be adjusted in some way to suit the wearer's personal hearing impairment. This is because not everyone is impaired to the same degree and not everybody has complications with the same frequencies.

In addition, the environment you are in can make a lot of difference to the effectiveness of the deaf aid and therefore, modern units permit the wearer to filter out some ambient noises like wind rush or heavy machinery. There is also much greater volume control than before. Volume control can even be set on automatic.

The fundamental form of hearing aid is the analogue system, the same type as was first invented for batteries but much, much smaller. These are usually BTE (behind the ear) units. The next sort is the programmable analogue hearing aid. This device is programmable for use in different situations and is a great advance on the simple analogue method.

The last type is the modern digital hearing aid. It is also the most effective and the most expensive. Its circuitry is capable of Digital Sound Processing or DSP. These digital aids use many millions of sound codes to identify frequencies and then either filter them out or amplify them. The difference is like converting from vinyl records to CD's.

Owen Jones, the writer of this piece writes on quite a few topics, but is currently concerned with hearing aids comparisons. If you would like to know more or check out some great offers, please go to our website at Digital Hearing Aids Prices.




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