Sonic Barrier damping sheets vs cork

No other comments, specifically about the merits of cork as a damping  material? 

I like cork quite a bit particularly around circuit boards and transformers. Lead not so much.

I have a friend (Pete Curry, bassist/recording engineer in Los Straitjackets) who put down a cork floor (over concrete) in his studio. Sounds pretty good---cuts down on reflections, but is not too dead. So Geoff, how come no likey lead as mass damper? I'm about to put some little stick-on lead weights (like for wheel balancing) on the counterweight of my pickup arm to increase it's mass (so's it can be closer to the arm's pivot, thereby lowering it's effective mass). No?

In most applications I’ve tried lead it hurts the sound especially in the bass, makes it sound weird. And lead seems like SUCH an ideal material. Not too soft, not too hard.  Lol  Maybe you will have better luck than I.

Cork would not be helpful.