left image is IBVA direct ( mean use IBVA AD )

right image is Mac Sound Line input ( mean use Mac AD )

both same brain head amp that inside of IBVA, however to Mac sound line input is no high cut filter.

IBVA setup is 960 Hz sampling, 320 Hz -3dB high cut filter

direct out is 1000 Hz -3dB slow high cut filter.

Test with 5 Hz sin wave and 40 Hz sin wave.

drop power for 5 Hz is because of Mac Line output and input filter.