EVM12Ls sound great in closed back cabs. They are an articulate speaker and really cut through the mix. I actually like them better in a closed back than an openback. In an openback, they tend to sound a little harsh at times, IMO. The closedback tends to remove some of the piercing/harsh highs.
They are also most people's choice in Mesa Thiele cabs. And they were also used in the closed /bottom section of the old Mesa Steel Grill 4x12 cabs.
Just keep in mind that they are very articulate, cutting, and clear, and won't distort or color your tone much.