Connecting Gold Phantom to an amp and/or sub

[ogs]

If bass is too strong the placement of the speaker in the room is probably part of the problem. If you cannot move the speaker due to furnishing your only option is using an equaliser based on measurements. Again a MiniDSP SHD would help you here. REW (Room Eq Wizard) with a UMIK-1 is good for measurements. I believe REW can export EQ directly to a MiniDSP unit.
Adding a subwoofer would most likely complicate more than solve things.