Dynamat for rear seat backrest

Hi folks,

I'm thinking about laying down Dynamat in my car.  My question is if I cover the backrest of the rear seat won't it interfere with the bass reproduction from my subwoofers in the trunk (facing toward the rear)?  It seems to me counterproductive but that's what the Dynamat says to do.

Also,  I'm going to cover the floor and firewall (for engine noise), as well as the trunk.  I won't be doing the roof (too much work!).  Does that make a big difference?  I think I'll use the Extreme version.

Are other brands as good or better than Dynamat?

Thanks.

Sound damping on sheet metal reduces or eliminates the noise produced by the sheet metal...not the mo' better noise produced by the subwoofer.  That rear panel is absolutely a critical place, as well as the trunk lid.  Any place where you are installing mid woofers is critical, too.  How much of the car's metal you damp depends on how much wattage the system is outputting, but it really depends on where you hear noise when you're trying to enjoy your system.  You can always add areas later...like the roof...if the metal is making noises.

http://www.sounddeadenershowdown.com/ is a very good non-compensated study of the various types and brands of damping available.  The author is a member of this forum.