Cone impedance question

I own  pair of nice 2.5 way, 4 ohm floorstanders and recently destroyed the 2 woofers on one of them. The story would be too long so I'll spare you.

Since no replacement parts are available (per the US Distributor) I had the bright idea of acquiring a used pair of the matching 2 way bookshelvers which also feature the "same" 5 1/4" cone, with the intent of canibalizing those cones to fit in my broken floorstander. I found out the "same" is not quite.

The cones are almost identical physically, those removed from the bookshelves have a cover over the magnets that I assume are a magnetic shield but the fundamental difference is impedance. The broken ones are labeled as 7.2 ohm, while the replacements are 3.6 ohm.

While installing I have balanced the cones so each floorstander has one 7.2 ohm and one 3.6 ohm cone, rather than one speaker (original) with two 7.2 ohm and the repaired with two 3.6 ohm cones.

When listening I am not noticing any differences, but then I haven't listened to these speakers for over a year.

I am looking for comments on potential implication. For example

• I have changed the total impedance of the speakers. Am I now at less than 4 ohm?
• Any one know of any obvious sound implications? I would assume the voicing of the cones would be the same even though the impedance difference.

Any comments would be greatly appreciated. Thanks,

Javier