Different brand/model Sub(s) integration


I have an all analog setup, the speakers are 2 Tannoy Kensington and one REL s/510. 

I have a room mode at around 30Hz, that I can't fix regardless the REL's location. The only viable solution I can see is to add another sub, because the REL does not have DSP and no bass-trap can effectively absorb it.

Do I need to add another s/510 or I would be better off adding another brand with DSP so I can null the room mode? 

128x128astolfor

Yes get another and stay away from bottom firing subs, unless they have a butt plate or a fixed slot that doesn't use the floor. You CANNOT decouple that type of sub.. I quit using them in the 80s.

SVS or JL or GR OB servo subs. Sell the REL and buy a pair to start with. IBs ported or passive radiators just NOT firing downward with an open bottom.. Kid stuff OP, pure kid stuff.. I been building bass enclosures for 45 years..  No one around me uses them they are the blight of the neighborhood. Makes everything vibrate.. Even the kids are decoupling their subs and mass loading the tops with springs too.. 

I am not a robot

Regards

Have you placed the subwoofer at the listening position then walked the room listening for the loudest bass mode? 

@oldhvymec +1 on the servo sub suggestion. Once you go servo you can never go back!

I am a robot.