upgrade my sound!!

I recommend a Stereo Pair of Self-Powered Subs. Front Firing, No Ports, located near the Mains for excellent Imaging. 

Very low bass starts mono, then becomes directional by either the not too low fundamental and by the bass overtones.

Add 2 subs. Three will give you incredible smooth, tight, articulate and deep bass like you won't believe. Do not sell one, add two. Put each one a different distance from a corner.

Right now with one sub there are areas where the bass waves cancel creating a dip or drop-off. So you turn it up and this is what creates the boom. Running more subs in different locations moves these areas around until the overall response winds up being very smooth and even. Smooth bass is fast accurate bass. It will also go a lot deeper. Incredible improvement.  

Room acoustics uber alles.

Yeah I’ve been intrigued enough about the 2 sub discussion to try it.  When I first got into the hobby about 20 years ago the conventional wisdom was that was unnecessary but it seems like everyone is recommending it now.  I won’t do it in two channel as I wouldn’t have the room and I’m very happy with that system now

The most effective, easiest and actually cheapest solution is four subs. The number of subs is far more important than how big or powerful or any of that. So no it is far from everyone is recommending it. Most are still stuck in the old school EQ one sub approach. A few now are starting to realize more is better. But then they get stuck in the rut of thinking stereo. Low bass is not stereo. Timing, etc, none of the usual stuff applies. Just get four, you will not believe. The last guy to do this PM'd me with, and I quote, "F---n f--k this is awesome!" Just do it.