Most owners should notice that the bass of this model is rather weak and the tendency to produce those irritating "thuds" rather "doong" for drums.
I found a simple way to reduce this and improve the bass. When I dismantle up the speakers (yes, I tend to open up everything I bought), I notice there is a pretty thick layer of grey sponge lining on 1 side of the wall and on the floor. Its not glued and I simply remove them.
You might have to unplug the speaker wires. If you couldn't remember which wires goes to which terminals, I recommend you to label them.
After removing the foam on 1 speaker, I notice a change in bass on that speaker (standing in front of each speaker to test for any difference). The bass is stronger and drags longer. Thus drums are no longer "thud thud" but towards "thoong thoong" now. Not sure if it should sound that way but it definitely sounds more plesant to me.