Inserting the bass reflex plugs
If the speakers are close to a rear wall or in a shelving unit, the bass may sound too strong. Inserting the supplied foam plugs into the bass reflex ports can improve the sound in this case.
Insert the plugs
Insert one foam plug into the bass reflex port on the back of each speaker as illustrated.
Notice
Never push the plugs completely into the bass reflex ports.
Also check the speaker positioning.