Why is the thiele small parameter Re less than the rated impedance for a speaker?

For example, I am considering whether to get a dual 1 or 2 ohm Fi BL. The dual one has an Re of 0.7ohm and the dual two has an Re of 1.4.

I have an Ultimate T3-1000D that is 2ohm stable (although the manual shows them wiring in a 1.5ohm load). So if I series wired the dual one ohm BL would I be ok? Or should I series wire the dual two ohm to be safe?

 

Re is the DC resistance of the coil of wire. Impedance is the AC reactance of that same coil of wire as it passes through a magnetic field. Somewhat related, but not the same thing.

Try this. Put a DMM on the speaker leads, set on resistance. Now push on the cone - you will see the number fluctuate as the cone moves.

 

all those numbers are nominal. most of the time a speaker rated at 2 hms can be less or more. just think of the 1.4 at a 2ohm nominal sub