Noise to reduce the distraction associatedwith transient soundsSound travels

Noise is unwanted sound. It has 3 effects depending on levels:-High level – mechanical changes in a person like heatingof skin , vibration of the eyeballs or internal organs.Low level – biological changes like elevation of bloodpressure or stress.Lower level – psychological effects like annoyance andcomplaintsSteady sound :Are the background sounds in any environmentIt is continuous and on long termCould be tonal or randomCould be accepted as normal soundTonal sound create more annoyance than the random sound- Transient sound :Such as : conservations, paging, machine sounds. Road trafficThey are mostly short termCan vary in levelCould cause distraction to a personThe use of sound masking is to reduce the distraction associatedwith transient soundsSound travels in waves and spread in all directions from thesourceReflected by hard surfacesBlocked by wallsAbsorbed by soft surfaces( Ever hear the saying, “it’s so quiet you could hear a pin drop?”The reason you can “hear a pin drop” over distances is becausethere’s nothing to cover or otherwise impede the sound frombeing detected by your ears ) .We believe that (quiet) is the low background sounds, whenwe are annoyed we believe that ( quiet ) is what we aresearching for. But what we really searching for is the freedomof the acoustical distractions that cause annoyance. The onlyway to achieve true quiet would be to maintain a lowbackground sound level with no transient sounds ( a conditionthat requires complete isolation from all activity sounds ).So quiet is actually the absence of the distractions around usrather than the absence of all noise which could be similar tosound masking definition.The main goal of sound masking is to achieve privacy and toprovide confidentiality of speech, especially in places like :closed offices, conference rooms and secure facilities. Even inthe open areas where people would want to be free from thedistracting soundsSound maskers can cover and hide sounds, but it cannotchange or eliminate them It is the addition of sound createdby special generators and distributed by unseen speakersthrough a specific area to reduce any distractions and makepeople comfortable whenever needed. Sound masker couldbe used in so many places such as : in houses, shops andcommercial offices, hospitals …Sound masking is so far the least expensive tool for providing privacy.They are special audio speaker systems that create uniform sound levels.They do not cancel sound but make conversations heard at a distance moredifficult to understand and so less likely to distract.Overcoming neighborhood noises, snoring sounds from other familymembers. It creates noise free environment for reading or studying as wellas speech privacy.Speech privacy is achieved when speech cannot beunderstood. So if you are standing outside the room by thedoor, you will definitely know that someone is speaking butyou should not understand what is being talked about.In open areas speech privacy is less practicalWith sound masking the radius in which speech can beunderstood is greatly reduced by raising the background noiselevel therefore reducing the speech to noise ratioDirect Field Sound MaskingSound masking systems can beinstalled in a direct position in whichthe speakers are pointing downwardsfrom the ceiling and sound masking isemitted directly into the space. Thishelps to create even distribution soundfield.Indirect Sound MaskingSound masking installed in indirectposition in which speakers are hiddenabove the drop ceiling and soundmasking is pointed upwards andreflected off the ceiling deck and backto the environment space.Closed officesClosed offices are done to provide privacy but actually may not besuccessful. why?walls can transfer the sounds ( walls are sound transparent) , so speech canpass to the next offices. Sound masking can be used to achieve good privacy.- Open officesOpen offices transfer sounds too clear. The conversations of others can beclearly understood and hearable . Sound masking raises the backgroundlevel to make up for the absence of walls that would otherwise block thesound.- Sound Masking in Medical FacilitiesResearchers shown and discover that medical buildings are similar toopen offices , they both transfer sound very we need toprovide sound masking in many locations to achieve the good privacy.For example , in nursing area , corridors and patient room and more.Exterior walls are heavier than interior walls since thematerial for the exterior are more and stronger. So exteriorwalls not always need audio protection. Un like the interiorwalls which is needed .?when someone speaks , then the speech will effect the wallby making vibration , these vibration may read and detectconversations by :laser or directional microphones by a remote .on the far side of the wall with vibration detectors or directlistening.within the wall cavity with vibration detectors or fiber opticmicrophones.To avoid this –> Vibration sound masking devices provideprotection .masking device should be placed in the room at aappropriate height and spacing on the wall.Masking protects the wall panels, the wall cavity, and beyondthe wall, while the masking levels in the secure room do notinterfere with speech.Sound masking in doors :Doors are weak and there are types like hollow or solid core,metal and more.Every door has a gap around its. So sound may be heard bydirect listening or other methods from doors. Since the soundpaths through and around a door,to avoid this -> vibration sound maskers are used on doors.Sound masking in ducts :Most of modern rooms have supply ducts that connect to aother rooms. So Ducts can be effective speaking tubes.Sound can be heard and detected by:Direct listening.with probe microphones .Vibration devices within the duct where they are not visiblefor inspection.To avoid this -> Vibration sound maskers is used