When fitting new front speakers is it best to screw them direct to the inner metal door panel, or have a form of 'cushion' created to hold them tight against the metal?

My front Vibe BlackAirs just arn't sounding quite right and sound very 'muddy' with the bass when the music is turned up to medium-slightly loud conditions. I wonder if this is because i cushioned the speakers with a layer of sound deadening to prevent them being screwed direct to the metal door frame?

Cheers guys!

Check and make sure you headunit has enough power to run these, I have a funny feeling they will need amped to work right.

Also might be an idea fixing direct to metal and using some sound deadening material to cover the door panel to give it more solidity.

I have a Vibe Blackair AMP so power shouldnt be much of an issue I hope! thanks though