A screening check to see if a radio earpiece is loud enough to damage hearing. Work down the steps and type in the numbers as you go.
Install a decibel meter app on a phone. Search your app store for sound level meter or decibel meter.
Pick one that lets you turn on A-weighting and shows the highest reading. Apps published by health and safety organisations tend to be the most accurate. This phone is now called the meter phone. Take its case off.
Open the app settings. Turn A-weighting on. Turn Max hold on. Turn off anything called noise reduction.
Go into a quiet room. Shut the door. Turn off any fans.
Hold the meter phone still and read the number with nothing playing. Type it in.
If it is over 45 the room is too noisy. Find a quieter one.
Get a second phone. Put a recording of someone talking on it, set to repeat. This phone is the talker phone.
Tape the talker phone flat on a table, speaker facing up.
Start the recording. Hold the meter phone's microphone 2.5 cm above the talker phone's speaker. That is about the width of your thumb. Turn the talker phone's volume up or down until the meter reads 90.
Leave that volume alone for the rest of the test.
Put a piece of tape on the table to mark exactly where you were holding the meter phone. Then put the meter phone down.
Take radio 1. Hold its microphone on the tape mark. Press the talk button and tape it down so it keeps talking.
Take radio 2 into a different room, or at least 5 big steps away. Plug the earpiece into it. You should hear the recording through the earpiece.
The test
Turn radio 2's volume all the way up.
Press the earpiece firmly onto the meter phone's microphone. Wrap a rolled up tea towel around both to block out other noise. Read the number after 20 seconds.
Do it three times. Take the earpiece off and put it back on between each one.
Now turn radio 2's volume to the setting people actually use day to day. Do the same three readings again.
Skip this step if everyone uses full volume anyway.
Borrow one or two different phones, ideally different makes. Repeat step 12 with each one and type in the average of its three readings.
If the phones agree, that rules out a badly inaccurate microphone and the error range narrows. It cannot narrow all the way, because every phone shares the same sealing problem. If they disagree by more than 10 dB the test is invalid, since that points to a leaking seal rather than a difference between phones.
Your result
Where you sit against the action level
Exposure at full volume
Where the errors come from
The right-hand column shows whether testing on more phones reduces that error. Anything marked no is shared by every phone and stays no matter how many you use.