Damping Factor vs speaker sensitivity

I have met many DF zealots over the years, and I'm glad to read that obsession is not being amplified here.  A JBL engineer whote a paper in the late 60's debunking the idea with math and logic. 

The DF Debate

Floyd Toole, director of Engineering at Harman (JBL parent) reprises the effort for the next generation of the technically misinformed here:

DF Nonsense

If the goal of specifications is to characterize a component's ability to faithfully convey the signal fed at the input unaltered to the output, it's clear DF is not an important measure as long as it's above 40.  1000 is not better than 40!

@crustycoot

@atmasphere has eloquently made this salient point a number of times on this forum.

Charles

@crustycoot +1

I agree with George L. Augspurger, in my opinion a damping factor (DF) of 4000 is pure marketing baloney! My Crown Studio Reference One Amp has a damping factor (DF) of 20,000 more marketing baloney. 😎  

Mike

and as @theaudioamp points out, when the theoretical DF if huge, the realized damping factor is much less, due to factors like impedance of the cables and connectors.