Just bought a 4x12" speaker cab loaded with old Celestion G12T-75 speakers (80s or 90s)... my friend is taking two of them out for his own 2x12" cab, so I need to replace the speakers with something else.

I've decided to get Celestion Vintage 30s to fill in the two spots in the cab... the speakers I already have in there are 16 ohms, wired up to be switchable from 8 ohms or 16 ohms on the back of the cab.

I have very little experience with guitar cabs as I used to use a combo. I've never had to mess with speakers or wiring them before...
If I want this cab to be 8 ohms switchable to 16 ohms, do I need to buy 16 ohm vintage 30s? I can't find them anywhere, only the 8 ohm ones.

Any help or wiring suggestions would be awesome!
Yes, they would need to be 16 ohms, if you used 8 ohm speakers the 8 ohm speakers would receive more of the signal than the 16 ohm speakers (electricity seeks the path of least resistance). Not to mention the final impedance would come out all funky, 12 ohms I think.

Also, fyi, that cab would only be using 2 speakers when its switched to 8 ohms.
I don't give a shit if you listen to me or not
Ok i'm trying, so i hope this isn't a necrobump. Anyhow I have a somewhat rare Crate 4x12 vintage club series cabinet loaded with Vintage 30's. It's 27"x27" rather than 30x30 and rated @ 4 ohms. I am considering changing the speakers and was thinking of using the 'texas heat' & 'swamp thang' combo which i believe are rated at 8-16 ohms. would this be ok?
hey loop de, if u just get speakers with the same ohms with the ones you take out, you should be able to wire them up the same.

and kitsch, any 4x12 cab that is 4 ohms is actually 4 16 ohm speakers wired parallel. its best to match the ohms on your speakers, cause if not your risking blowing up ur amp. when you mix 8 and 16 ohm speakers, it will give you a value in between the settings of what your amp operates. so b careful not to **** up. lol