Damping Factor vs speaker sensitivity

I would not think so. Damping factor affects mainly smoothness of frequency response, because it is inversely related to output impedance of the amp. A high DF gives smoother frequency response on a speaker whose impedance varies with frequency (most of them).

DF is frequency dependent and conventionally measured at 1 kHz. Unless you have a graph of DF showing it is 4000 at higher frequencies, it is probably lower there (though maybe not relevant to your question).

I don’t know if this applies to your situation, but sometimes distortion in the high frequencies can masquerade as more extension. If the Hegel has lower distortion than a previous amp, it could give the impression of less extension. I've not listened to any Hegel amps, so I don't have any insight there.

There is inductor resistance, voice coil resistance, resistors, capacitor impedance, inductor impedance. Your real damping factor is never anywhere near 4000.

Damping factor is pretty much meaningless unless one is talking about a tube amp with extremely low damping factor, like around 4 or less.  Beyond 8, the numbers don’t really matter that much unless the speakers have a really low impedance.  

theaudioamp, I have already seen >900 DF on a Hegel publication. Looks like they changed the way they measure it?

mike_in_nc, May be a greater smoothness give the impression that the high frequency did not sparkle as it is suppose to be, for my taste ?

A high damping factor (DF) is indicative of two things

The amplifier has a low output impedance (Which is inversely related to DF).
Generous application of negative feedback (NFB).

I have yet to come across a reasonable explanation as to why a DF of > than 40-50 or so offers any meaningful sonic benefit. I agree with the comments/perspective of @larryi above.

Charles

@audiosens 

Yes technically an amp can have a damping factor that is very high as it is measured at the amp terminals.  I was listing all the parasitic values in a system between the amp and speaker driver that makes this value meaningless.

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.