I closed these late yesterday but then turned them off again over night.  I've collected overnight spectra now and have re-closed the loops.  I'll make comparisons with the HEPI L4Cs and the ISI T240s for evidence of minimal harm from the loops.  Attached is the comparison--I'll examine it closer too but I think there are elevated areas with the loops on between 0.7 and 10hz.  Maybe we can live with this or tune this out.