Coupler response different between Verifit and Aurical

We have recently noticed differences between the coupler response values (2cc) obtained with the Aurical and the Verifit equipment that other centers use. The coupler response in the case of the Verifit is flatter, smoother, while in the case of the Aurical, it shows some peaks.

Is this due to a different measurement technique, input signal or the way the results are presented? Is a kind of average?

I rule out any calibration error since the curves shown in the Natus documentation are very similar to those we obtain.

Anyway, the RECD are OK, since they are the differences between the coupler and real ear responses… but still some people ask about the differences in the responses between the two brands…

I attach 3 pictures to show you what we see:

We obtain something very close to this:

[image]

This graphs in your presentation shows coupler and ear response

[image]

And here, the upper curves show ear and coupler response with verifit:. They are smoother:

[image]

Could you help us with the reason of these diferences? If the input signal itself is different (it seems it is not white noise), that could be the reason?