% freq (Hz)        realZ            imagZ
20                 120              -993
25                 120              -993
31.5               120              -993
40                 120              -993
50                 120              -993
63                 120              -993
80                 120              -993
100                120              -993
125                962.4            -1324
160                908.25           -1196.45
200                842              -993
250                999.99           -900