Why do I get different frequency responses in EASE and the GLL Viewer?

The reason for this is simply different calculation intervals in the basic settings of both EASE and the GLL Viewer.

The excitation signal in EASE is pink noise, calculated as follows:

The AES2 standard signal is set band-limited for the cut-off frequencies 88.4 Hz and 11.3 kHz (band limits for the one-third octaves from 100 Hz - 10 kHz)
The maximum input voltage (MIV) the system can handle with this signal is checked
The resulting broadband signal level is then evenly distributed to all one-third octave bands (pink), which means each band is reduced by 13.22 dB (10 * Log10(21))

If you wish to compare frequency responses of the GLL between the GLL Viewer and EASE, please use the following settings in the GLL Viewer:

As EASE only evaluates and uses a frequency range from 88.4 Hz to 11.3 kHz (band limits for the one-third octaves from 100 Hz - 10 kHz), please set those limits in the GLL Viewer’s Calculation Parameters for the AES2 Band-Pass Input Signal. The frequency response shown in EASE and the GLL Viewer should then be comparable.