Sounds good then. The G40 isn't bad or anything, in fact it will still work quite well. The LX60 isn't all that different, but this was my preferance for the reasons given. I'm sure you'll be happy with the G40 though. Its similar to a lot of other high end 18" drivers.

I'd have the 18" in a seperate enclosure from the rest - a subwoofer. I'm assuming that the 12" can reach to below 100Hz (I have not checked myself), below 70Hz would be the best. The G40 18" needs over 300L box volume so you can't really have the 12" and HF horn in the same cab. In any case, I'd rather have the 18" seperately anyway. The 12" driver your using needs to reach at least 70Hz. Have the 12" and HF horn in the same box with the 12" on the bottom, and HF horn on the top. The 18" goes in another box. This will also let you place the subwoofers each in a room corner, and have the 2-way main speakers out in front which is a good setup.

I don't know how much the Beyma's are worth, in fact I live in Australia so its pretty hard for me to give a US$ price.

> Will the 18" back-air(air backwave) affect the 12" and the horns?

If they were in the same cab, you're right, the G40 and 12G320 each need to be in their own seperate enclosures. The HF horn can be in the same compartment though.

"CP650ti (2" exit driver), CP25 and a TD400 horn"

What is the CP25? Is it a supertweeter or something that doesn't require a horn? If it is, then I'd have the 12" driver on the bottom, HF horn in the middle and supertweeter at the top.

Have you made sure that your tweeter horns provide the correct response curve and such.

Adrian