Hi, I have a THX certified subwoofer, I leave the volume behind it at the reference level (slightly below the middle of the maximum volume) when turning the water on the receiver onkyo tx nr757 it turns the sub volume on + 5db should increase the volume on the subwoofer (Above the reference volume) and lower the volume in db on the receiver or should I leave as the acueq arrow on + 5db ??