audio sound analyzer

this gadget used to calibrate sound pressure level ranges from 30hertz-20khertz suited for human hearing level [login to view URL] has an independent frequency level. it could measure through calibrated level panel for sound pressure level called as [login to view URL] is used for concert or auditorium for sound frequency calibration.... its very useful enough to all sound engineers.....installers.....and various used in public places like gym's....halls.....buildings etc..... with it could solve problems of out phasing. of sound waves. and it protects human ears for various hearing defects that erring sounds that had giving to human being.....