Residential condo unit over top of a bar and kitchen.  Floor assembly from bottom up is sheetrock ceiling finish, 2x10 floor joist.  Fiberglass batt insulation in between joist bays.  Two layers of 5/8" CDX plywood (felt paper in between layers).  There is some noise coming up, mostly from the bar when it is busy.  This is more of a restaurant with a bar that gets busy.  Its not a night club that is hosting Metallica on a regular voices.  Airborne noise is mostly loud voices and laughing that increases after that fourth or fifth beer.

I have talked to some folks, done some reading online, have heard some different options.......anybody have an suggestions or expericences with underlayements or barriers that may be insalled under a carpet.  The space will most likely be finished with carpet and some limted ceramic tile. 

Thanks for any feedback.

Talk to a professional sound control company...maybe these guys to start with...
http://www.soundproofingcompany.com/company/

whg; I have used cork under ceramic tile and can be used under carpet as well. http://www.quietcork.com/ It gets glued to the sub floor, I would also try to get to any wall / ceiling penerations and plug those up

Looks like the site Garth suggested is a pretty good one. For many of their suggestions, you have to be REAL searious about wanting the sound out. One good rule of thumb: Higher frequencies are filtered out with insulation (of many types.) For low frequency, you need mass. Concrete being the most readily available.

Before replay visit some sites then you idea how much perfect installation for your home noise if you visit Google search engine then you get better way for the home noise.

I think I would have to agree on Garth and second Jerry's opinion. Although,you may find others when you search you'll have to make sure they are reliable!

There are a few underlays out there than will make a bit of difference to the noise. Make sure that the cavity in the walls is insulated fully , as this is where most of the noise will travel from. I spent a lot of money on high density underlay because I could here the TV from downstairs this is a very expensive type of soundproofing building materials. But the sound was only slightly dampened. I then realised that the noise was coming up through the cavity. So check that you have it.

Your best bet will be a lightweight concrete with carpet installed over the top.

SPF also work for that. If for making it noise proof.

Thanks for the help. I have done some research and spoken to the soundproofingcompany several times. Their first piece of advice was to take an inexpensive stethascope and put it on the various construction elements and see where the noise is coming from. I have some hi-density batts I just installed and some previously existing fiberglass still installed. Was interesting to see the difference in sound transmission through the two. Long story short, I am going to use a combinaiton of double studwalls, offset studs and green glue everywhere possible. It does cost money but the space is relatively small and its a lot easier to do it now then 6 months down the road when the space is all built out.