Evaluation board uses 10Kohm Ri, and 10uF Ci

https://www.diodes.com/assets/Evaluation-Boards/PAM8406-User-Guide.pdf

Data Sheet

https://www.mouser.com/datasheet/2/115/PAM8406-247303.pdf

Has gain set by;

AVD = 20*log [2*(RF/RI)]

If i understand correctly RF is fixed at 142kohm. RI must be 18k minimum (confusing as the dev board above uses 10k RI)

Looking for a smaller gain as this is a 5v design, i'm planning to use to drive 3w speakers, i'm looking at using something like 62kohm Ri.

Ci is calculated by the following formula, based on the frequency cut-off(Fc) your looking for.

Fc=1/(2*pi*Ri*Ci)

Using Ri 62000, Ci would be 0.09uF, at 30hz Fc (lower than necessary for such a small driver)

Using Ri 10000 as on dev board, Ci would be 0.5uF at 30hz, despite the fact the dev board Ci is 10uF.

Are they just using a much larger cap than necessary? Or am i calculating something incorrectly?