Can Sound isolation clips be used with multiple layers?

Hi, first post by me! I've been reading up on this website for a while now and have bought Rod's book over the winter, very helpful in deciding on how to treat my basement! I have some guys coming to install the drywall later this week and I am not finding the info I need to make sure I can communicate with these guys exactly what to do with my ceiling. My plan is to use whisper sound clips on a channel running along the joists, and I wanted to use two layers of 5/8 gypsum (hopefully with green glue). I don't quite understand the installation methods, but how are they to attach a second layer of drywall while keeping it decoupled from the joists? Is this even possible, and how so? I certainly don't think that screwing the second layer right through and into the joists would be a good way to go about it, it seems that would defeat the purpose of me putting up those clips in the first place. Is it a matter of me choosing between one layer of drywall connected to the joists through the whisper clips or 2 layers w/ green glue sandwiched between screwed directly to the joists? So what sayeth the gurus? Hopefully I am not doing this... :horse:.... but I am having trouble finding it online. Bryce Hotz Omaha, Nebraska.

If you look at the installation instructions for the whisper clip, you'll see how it's done: http://www.soundproofingcompany.com/med ... asheet.pdf Install the clips on the joists. Mount hat channel into the whisper clips. Attach the drywall to the hat channel. Using this method, there should be no way that the screws would couple the drywall to the joists. Oh, make sure that the hat channel runs perpendicular to the joists. Hope this helps! Andy

Oh nice! I was looking at it backwards, thinking that the hat channels were installed on the joists as opposed to the clips. That makes a whole lot more sense. Thanks buddy.