Does anyone know where the warning:
WARNING: FIR normalized: sum[coef]=9.781101E-01;
comes from when removing the instrument response from some IRIS data?
The interesting part is that sum[coef] seems to be always =9.781101E-01
(even in similar threads:
Is it some kind of systematic error?
Even though this seems to be a common case, I couldn't find an answer to
this in the internet. Also I think this error doesn't come from obspy
but from the underlying libraries, correct?
Does anyone know the answer or where to find it?