What kind of filter/filters are being used in this feedback loop?
Start out by removing the series RC 33K/10nF.

The remaining 10nF ensures the DC gain is ONE.

The 100pF ensures the very high frequency gain also is ONE.

The 100pF in parallel with 10 Kohm is 1uS tau, or 160KHz F3dB.

The 100pF in parallel with (10K + 100K) is 11uS tau, or 14 KHz F3dB.

Now add back in R5 (33K) and C3 (10nF); Tau is 3.3e4 * 1e-8 = 3.3e-4 => radian frequency of 3KHz, F3dB of 500Hz (2 octaves above middle C).

R5 and C3 being parallel with R6, provides 4dB boost in gain above 500Hz.

What is the gain? The minimum gain is set as 1 + 10K/27K or 1.4 or 3dB.

The maximum gain is set as 1 + 110K/27K = 5 (14dB)

And do not forget about the boost in gain, from R5+C3