bl, cone area, wattage, and the box and its tuning.
are those not the most important things? add or take away if i am wrong, because i most likely am.

 

motor strength more important than xmax??

u need to do more reading...I wouldnt say more important... just equally as important... simply for the fact you might have a BL of 100000 but if the sub only has the potential of moving 1mm p-p then ur not getting loud period!

the box is the SINGLE MOST IMPORTANT!
the rest is a money game!

 

well is it not true that 100W would be louder then 1W?

 

Back to my original question then...

If you have two speakers with the same xmax and SD, but different wattage, what determines which should be louder in free air?

The motor strength?

Let's leave boxes out of it.

 

I think efficiency would play a factor in that equation... a more efficient sub would do better with lower wattage in that scenario... as for what determines efficiency, I'll leave that to the pros

 

well theory would say the most displacement overall would create the most pressure... sound im not sure of...

 

are you asking this question to help you save money on your next stereo purchase?

what is SD?

i always thought xmax and displacement were two diff things?

 

I'm asking this question to figure out how to determine which sub puts out a higher SPL on paper, excluding the box.

SD=cone surface area

Displacement is the amount of air directly moved by the sub.
SD x XMAX = DISPLACEMENT

(i.e. a surface area of 50square centimeters moves with an xmax of 1cm means 50cubic centimeters of air would be displaced)

Apparently motor force has something to do with this too.
The amount of power needed to reach the maximum xmax maybe?