While conducting an annual hearing conservation plant visit for one of my customers, I ran into a situation of what NOT to do when cleaning an audiometer headset.
Before conducting a calibration, I always perform a listening check. I clean the headset jacks at all three connection points (starting from the back of the audiometer), and listen to a 1000 Hz continuous tone to ensure that the earphones are producing an uninterrupted tone when the earphone cords are flexed. In this case, all was well. After setting up my calibration equipment and mounting the first earphone onto the coupler, I noticed that the output was off by 2-3 dB for all of the frequencies. This is highly irregular for any audiometer. Fortunately, I was able to adjust the output and bring it up to ANSI specifications…until I got to 6000 Hz. As much as I tried, I was not able to adjust the output beyond a certain point. I ended up telling the customer what I found and said that the audiometer was going to have to be sent in for repairs (if necessary) and calibration.
Out of curiosity, I decided to call the manufacturer with the thought that there might be something I missed or that there might be a “field fix.” After telling my point of contact the problem I found, he stated that, in the course of cleaning the headset, any liquid that gets on the diaphragm of the earphone (past the black grid) can over time “clog” the diaphragm and affect the output of the audiometer. He stated that this affects the output particularly at 6000 and 8000 Hz. The only fix for this would be to replace the earphones and recalibrate the unit. Cost. . .several hundred dollars!
After my phone call, I asked the customer if she cleans the headset regularly. She said that the headset is cleaned after each use. When asked how she cleans the headset, she stated that she takes a can of aerosol disinfectant, and sprays the entire headset. That was my “AHA” moment! I relayed to her the conversation I had with the manufacturer and what she was going to have to do.
Thus, the following reminder: ALWAYS CLEAN THE HEADSET BY HAND USING A WET WIPE, ENSURING THAT NO LIQUID ENTERS THE CENTER GRID OF THE EARPHONE!