Acoustic doors?

Thank you all for your helpful respsonses and references. One of the aspects I love about this hobby (or profession for some) is the chance to apply science and test theories in solving problems. I now have some more food for thought, and for a temporary fix for my leaky door I will try hanging my 30 year old Coleman sleeping bag over the door. This will ad some mass and create a 5" air gap. I will post the effectiveness shortly.
For a more permanent fix, I'm thinking a heavy exterior door with good seals would be the most economical solution. Can anyone recommend some good manufacturers of such doors?

I have headphones and use them when I can. However, there are a lot times when headphones are not an option.
In any case, I was able to tighten up the door tolerances and temporarily hang two cotton and one wool blanket over the door. I have achieved a considerable improvement in sound attenuation and the Mrs. is surprisingly impressed my blankey solution. It's kind of like entering the yurt when you squeeze through the blankets
I see installing a solid core 1 3/4 exterior door with the best weight to price ratio and imploying a good gasket along with stiff framing and hinges as the best solution so far. Then I can see where the next weakest link is. I can't wait.

Albertporter,
Thanks for the advice. I have a contractor that I have been working with and I will talk to him about purchasing and installing the door. It will pobably be few months before the job will be started.
Hopefully I'll remember to post the results.

Thank you Philbrady . This is exactly the kind of information I am seeking. I appreciate what a great resource Audiogon has become for me.
I have learned a lot from this thread and now I can see how mass, stiffness, and air seals all work together to make an effective acoustic door.
In the meantime I am tweaking my layered blanket door cover. It's actually quite nice as it gives the bedroom a cozy yurt-like atmospere that my wife, cat, dog, and I all dig.