Solid Hardwood, Engineered and Laminate Flooring - eneven subfloor

I am installing a Bruce engineered hardwood floating wood floor upstairs in my gameroom. The gameroom was added on years ago. I ripped out the carpet and the subfloor is plywood. It crowns in the middle and dips towards the outer and inner wall of the room. Any suggestions on what to do to level the floor prior to installing the wood fllors? I really don't want to rip out the plywood. Thanks

This is a problem. It sounds like you have had some settlement on the foundation. How high is the crown of the floor? You can check this using a long level to get an idea. Place the level on the high spot and hold it level and measure the distance from the bottom of the level to the floor. Most flooring types require the subfloor to be within 1/4 inch. There are several options for you to make the floor more level. First make sure that the subfloor is screwed or nailed tightly at the floor joists.
Depending on how much you have to build up in the low spots you can use a leveling compound, but consider how big the room is and how much you will need to spread out evenly and level....to bring the subfloor up to par.

Bob