Hi All
I was using multipole LP filters with my seismographs. They use the opamp non-inverting input. The note with the filter design says that the input " must return to ground via a low-impedance dc path". I wanted to reduce in half the input to the filter. I know the output of an opamp buffer would work but if I used a voltage divider w/o the buffer how low of resistor would be considered "low impedance". 

Regards
Barry