Best sub for B&W matrix 805

Has anyone used a Velodyne sub with the B&W Matrix 805s? If so what model #s?

Thanks Rogercr for sharing the info. It helps me get an idea as to what to do for when I do get the Matrix 805 bookshelf speakers. That particular Velodyne sub and Krell amplification is pretty serious. I will have to start saving funds just in case my gear isn't up to snuff.