Real Ear Aided Gain (REAG)
With the probe tube just in front of the eardrum, we measured the REAR .
That is an output measurement.
Now we can also choose to subtract the input (which we know from the reference microphone) from that found output. And then what do we have? … Of course the gain! So what the hearing aid has done to the sound.
The software of the REM equipment can also be used for an Aided Gain measurement via a prescribed target. We mention NAL-NL1, NAL-NL2 or DSL 5.0 as the main calculation rules.
We can therefore see whether the actual measured gain corresponds with the required gain, according to the prescription. If not, the hearing aid setting can be changed and the result reassessed with a new measurement
You can measure that Aided Gain at different input strengths. We often measure at 55, 65 and 75 dB.
You then have a good overview of the dynamics of the total speech area. An example of that is showed alongside.
In this way it is also possible to recognise compression of the signal.