This circuit can be used as a subwoofer pre-amplifier, the isochronic transmittance can be founded just with the inverting transmittance equation (T=-Z2/Z1). Z1 is the 1K resistor and Z2 the parallel assembly of the 16nF cap and the 10K resistor. Then, your just have to reduce this formula to get something like "T=To/(1+j(w/wo))" with "To=the 0Hz transmittance value", " w=The input frequency (rad/s)","wo=the cutting frequency (rad/s)".
Then, if you want to found the gain(dB) you just have to calculate "G(dB)=20log(T)" With "T" the transmittance founded before!
This circuit "cuts" the signal at 1KHz
