Implementation of active noise control for hearing test application using PC

Hearing screening test is a method to determine the disorder in human ears. Conventional audiometer and an audiologist are required in order to perform the hearing screening test. However, this procedure is difficult to be implemented especially in a remote site such as factory or school due to the ambient noise which may cause inaccuracy in the test. In this work, the application of active noise control (ANC) is proposed to reduce the ambient noise using a personal computer in hearing screening test. The ANC algorithm was implemented using a computer with data acquisition modules and LabVIEW software. The results showed that the anti-noise was successfully generated in the electrical domain but no reduction was observed in the acoustic domain. The ANC is a deterministic application that requires real-time operating system to respond to the input with precisely timed output. In order to have an effective ANC system, the processing time has to be less than 0.125 ms at 8 KHz sampling rate.