vintage fender bass

What kind of speakers do I put in this cabin Bass?
I have a vintage 1968 Fender Bassman with matching cabinet. The cabin is a 3 x 15. Two of the speakers do not work at all … the first and third in the group. I'm wanting to replace all three of the speakers, because the vintage speakers can not handle the lower my bass. I need to get three 15 "speaker cable and when they need to be at or above 4 ohms. I can not find any 12Ohm speakers, so I'll to go with 16Ohm. Does anyone have any idea what type of speakers you would be better to handle the low end. Legacy Eminence I was thinking but I have no idea. Any advice?
Here is a list of almost everything that is done and Defenses Peaveys than actual re-marketed it anyway in some of these brands. http://www.usspeaker.com/homepage.htm Look at the list. If it were me, I would get cheaper, and point (in fact I have thought about building my own quad-12 cockpit. And doing just that). BUT … You want low-end so look at all the low frequency response of the end of each speaker. Choose the lowest, cheapest, 16 Ohm speakers can be found (no rating power should be a problem, as it will be split 3 ways). 16 3-Ohm speakers in parallel is 5.33 ohms, so your Bassman should have no problem driving the set ..
Fender American Vintage 75 jazz Bass