[ricardojoa]

If bass is omnidirectional, shouldnt treating the front wall or the rear wall have the same effect on the frequencies below 100hz?
The reason for the front wall is because i dont want panels or pillar on the corners. I already have a small room so with those corner trap in, the place will look cramped. I would guess that broadband panels on the front wall should be a good alternative?

[DTB300]

In my experience, the Front Wall/Rear Wall Floor/Ceiling seams are a good place for bass trapping.   But not nearly as good as treating the corners of the room.   Corner trapping was a major change in my room as well as rear wall trapping. 

If you do not want to straddle a corner with a trap, you can put them flat on the wall to the left and right of the seam touching each other.   I believe on Real Trap site they have a picture of this as an alternative to straddling the corner.  I believe it came from a question about a door by the corner of the room.  Cover the door and the wall next to it.

But your room is your decision, and compromises must be made in each of our rooms.  Just know your bass trapping will not be as good as it can be.

[dsrviola]

"If bass is omnidirectional, shouldnt treating the front wall or the rear wall have the same effect on the frequencies below 100hz?"  No. The order of priority for trapping corners to control bass in a room should be front wall, then rear wall, then the midway point between along the  front wall. If you're unwilling/unable to use traps I'd recommend moving the speakers to the diagonal. That can fix quite a few acoustic problems in one fell swoop.