Modify response calculation for infrasound channels so it is valid
Related experiment: PIC 201939 Erebus Backbone.
This experiment has channels HDF, BDF, LDF (Centaur + Chaparral 64Vx2). Nexus calculates the response. It may issue a 'failed to recalculate overall sensitivity' message. Regardless of whether the instrument is re-selected and the response calculated again without that message being issued, channels HDF and BDF fail rule 412 of the stationXML validator: product of stage gains must equal total gain. Channel LDF does not fail.
Some useful information from Mary Templeton:
it doesn’t work well to just multiply the values of the gain stages for the total sensitivity. It needs to be calculated for all stages at the frequency value specified in stage 0 (or ), then those values get multiplied.
Requested behavior: Nexus to calculate responses for these channels (other channels such as ?DH may be affected, unknown) in a way that passes validation.