Panasonic tv speaker (bass sound) rattles

Hello my panasonic viera Speaker (bass sound) has tinny sound and rattless when the bass speaker is trying to give sound,

the more I turn the bass up the more rattley it sounds

And can't turn up volume as this also make sound rattle more

If I turn the bass right down so only treble sound is okay but volume is then to low and all treble no bass

Any suggestions