Danny do you happen have a model of anechoic FR of an LS-6 and how it would be affected by each bass management resistor?
No, I don't have my large anechoic chamber any more. So measuring to that low of a level on a speaker that large without room interaction is not possible.
Or a better analogy? im struggling to understand
like with a parametric EQ would it be centered on 70hz and then have -1 thru -5 db with a Q of 1?
You say first order roll off which is 6db slope correct? but then what happens when you move the pig tail around.. whats changing. The slope?
It is an LCR network shunt to ground after the woofer network. The trap area is centered at 70Hz. This is a typical range where a lot of unwanted room gain can take place with a speaker this large. The adjustments vary the resistive load across the circuit. More resistance means the LCR circuit is less reactive and the bass is effected less. Less resistance means a more reactive circuit allowing more power to return back to the amp verses passing to the speakers. So bass output is lessened.
The circuit centered at 70Hz has a first order slope in each direction regardless of resistance level.
LS-6 impedance curve showing adjustment:

LS-9 showing the same:

This curve shows only 3 adjustments levels on the LS-9, but there are 4 levels on the board.
And of coarse it can be unplugged on both speakers allowing no bass attenuation.