Noise is an unwanted sound that reacts with normal activities. Sound is the vibration that travels through a medium called air. It is also a physical phenomenon that is sensed by the human ear, weather that type of sound makes a pleasant or unpleasant way purely depends on the luster and their mood of activities.

The sound has three physical characters which are frequency, vibration, intensity. Depends upon the people their listing mode will differ, many people’s are love to hear loud noise but it is very danger which will cause hearing loss when frequency get into higher volume.

The normal background noise level is getting reacts with an acceptable noise level (ANL). Where ANL is the highest level of background noise is predicated by 85 percent accuracy.

It is the best recommendation for your patience. The special information is that the acceptable background noise levels is lower in female gender while comparing with males and also one of the reports found that the male gender has more tolerance than the female with ANL.

The people have hearing loss will have less ALN than the people with normal hearing. In older records said that the background music does not matter in ANL but in recent studies found that there is some relationship between background noise and ALN.

Where ALN is different from background noise and it will also get differ from the number of talks. Another study data declared that the people who have better speech understanding will have lower ALN.

In the older records found that the ALN will not differ for the people who use the hearing aid of unaided conditions and the latest break the theory that the people who use the hearing aid were they are in lower ALN.

There are many conflicting results occurs because the testing place and types of equipment are different. Based on the equipment the results will vary for every experiment.

The major test has been carried out to find the level of ALN with different spectra of the background of noise they are broadband noise, high and low pass filtered noise, high and low-frequency band passes the noise, all this moderately produce the sensuous hearing low and produce the low ALN.

The ALN groups are classified as 3 types, were low, mid and high. The low level in ALN is 0.3 and the mid is 13.6 and the high is 12.3.

Typical background noise levels will distribute hearing aided persons. So, many technologies are used to reduce the ALN which would help them to get the accuracy of the other voice without background disturbance.