A:Answer I'm not entirely sure joenj but, the box specs are 7.5 deep, 10 inch tall, and 7.1" wide, so based upon that I would estimate around 4.75" or 5.25" subwoofer. I have one, and it puts out some good sound. I just use it to hook my ipod or my phone up when we're cooking dinner or working on project stuff in the living room.
