Yep. I went passive about five years ago after owning Klipsch Promedia 2.1s for several years. I use an HK 3390 to power the Ascends and then the ODAC.
But you have the D1. Lot of people really like that DAC/headphone amp. Get the best speakers you can now to go with it.
Here's a review of the Airmotiv 5. The review says you need about 1 foot behind them. However if you moved them over near your corners aimed in toward you, with their edges a few inches out from the wall, they you would have a good bit of space behind them because of the corner. And if you can get them up in the air so they are aimed more at ear level, like with these stands (http://www.wood-tech.com/content/fgh-12 but find something cheaper), I think that tends to help, too, because the air has more room to move out and around beneath.