I just picked this up, buy the driver does not sound very good. If I didn't know better, I would think it was blown. Resistance between the dual coils is around 6.5ohms, each coil around 3.5. should they be 8 and 4 respectively?

Anyway, I think it may have seen better days and thinking of swapping out the driver and amp. Anyone know the internal volume of the cabinet? Would like to get a decent driver, but inexpensive. My quick guestimate is 1.55cuft

Edit: I think this is a bigger box than the OG 150. It's about 33".

Is there a port ? If so it would be worth measuring diameter & length of that as well.

There seem to be multiple versions of each of the speaker models back in those days so probably what you measure is going to be as close to golden as we get.

You mentioned "amp" - does it have a built in amplifier ? If so then I'm wondering if that might be the first of Axiom's powered subwoofers.

The port is 7.5L 3". diameter
Yes, has an amp bit doesn't say axiom on it as with others I have seen.

Some images
https://i.imgur.com/XBUUPN0.jpg
https://i.imgur.com/9MEXAhr.jpg
https://i.imgur.com/rWCU39N.jpg
https://i.imgur.com/tu4E5Hd.jpg