How to prevent speakers 'booming'?

[basite]

thats true there is a switch phase on the back off my subwoofer .but if i placed a floorstanding speaker in a corner. how would you get booming sound with speakers. i thought boomy sound can only come of really low frequencys like subwoofers.so if i place a bookshelf speaker in a corner would i get booming sound ??

you'd get more boomy sound than if you'd place them freely, with no walls really close to them.

the phase switch on the back of your sub is not the only thing, the equalizer switch is more important if you wanna place it in corners.