Below is an exampel of the SAC response file format. Note that if zeros are zreo, there is no need to write them. The response must be in displacment with unit meters.
ZEROS 3 POLES 4 -0.0123 0.0123 -0.0123 -0.0123 -39.1800 49.1200 -39.1800 -49.1200 CONSTANT 3.832338e+12
Note that the response file names must follow SEISAN response file file names with SAC at the end like e.g. KEV__B__Z.2000-10-10-0000_SAC.