Insuring your Audio Room?

We do have a homeowners policy which may cover all the risk. I have already informed the company about the room and the coverage should be in excess of the value of all the internal possessions including the room. However, I was thinking of getting another policy just for the room and it's contents, probably not simply a rider. 

I was wondering if anyone had experience with taking out a separate policy just to insure an audio room. Is there anyone who knows of a specific carrier that offers a product either designed or well suited for a dedicated audio room? Perhaps something which could also include risk of a flood, considering it's in a basement. The current homeowners policy doesn't have flood insurance and adding it would about double the cost.

I think I would like a specialized policy in addition to the basic homeowners insurance policy. Does anyone already have something like this in place for their own system?

I appreciate the responses so far. Thanks for weighing in!

Whart, thanks for your detailed suggestions! I'll take a look at the companies you mentioned. You mentioned special walls and electrical work. That's certainly something that would be important for some people to address. In my case not really but that's still a very good point. Thanks again!