I am trying to develop a hearing test that outputs different tones at different frequencies through the headphones. As soon as the user hears the sound, the corresponding decibel level should be recorded.
I know that there are already online digital hearing tests. But I wonder how they determine the dB level, without a microphone.
Currently, I am still failing to find a way to calculate the decibel level.
Here are my questions:
- is there a way I can derive the dB based on the volume of the headphones?
- while researching I often came across the term “calibrating headphones”. What does calibrating headphones mean in the context of measuring dB?
This really is a hardware problem. You say "find a way to calculate the decibel level". That tells me that you fail to understand the problem domain. It's not a calculation problem.
As a simple example why it's not, some headphones have an analog gain control. The exact same headphone, using the exact same volume setting in software, will produce different decibel levels.
Hence, the answer to question 1 is a hard NO.
"Calibrating headphones" is a fairly ordinary calibration activity, but your question 2 suggests that you're not familiar with calibration in general. In this context, it means that you determine using known hardware (a specific microphone, connected to known audio hardware) how loud an unknown headphone for each of its settings.
This is unlikely to help you - instead of using known headphones, you now need a known microphone.