A likely problem is your seating position is in a null point.
The following explains the mechanics of bass in a room. While the subject is subwoofers… it explains standing waves and will give you lots of info on how the room changes the characteristics of bass,
Also, it would be helpful to know your components and the venue. There is a place to put photos and your components under your UserID. This would allow us to understand your situation and be an order of magnitude more helpful. My systems are shown.