[SAC-HELP] Removing Instrument Response

[James Smith]

Hello:

I have a set of Canadian seismograms that I need to remove the
instrument response from. I have converted the seed files to sac files
and extracted the RESP files.  I am using the following commands in
SAC:

sac> file.sac
sac> rmean
sac> rtrend
sac> taper
sac> trans from evalresp to none freq .01 .015 2 5

When I use the evalresp file I get the following output:

 Nominal Calper not set. Setting Nominal Calper to -999.000000 to
match Wfdisc Calper
 Sensor Calper not set. Setting Sensor Calper to 1.000000 to match Wfdisc Calper
 Response appears to be Un-Normalized.
 Waveform appears to be unscaled.
 Wfdisc calib value is (769600000.000000).
 Waveform multiplied by 1.000000 after deconvolution.

The deconvolved seismogram usually doesn't resemble the original. My
understanding is that removing the instrument response should not in
general change the shape of the seismogram. I've tried applying
various bandpass filters without much luck.

Can anyone tell me if I am missing a step or what could be responsible
for my problem?

Thanks,

James Smith
Colorado State University