Marantz HD-880 floorstanding speakers

I purchased a pair of these it is missing one woofer so I would like to replace both woofers does anyone have any knowledge of these or a suitable woofer replacement. They are 12" woofers 8 ohm 90db/w/m the opening is 10 11/16" The cabinets are 40" high 16" wide and 12" deep and ported.

Thanks Tony
Go to the link below for some information on the HD-880.

You may want to look through audiokarma posts about this model and see if someone there can help you out.