Higher sensitivity - more dynamic sound?

@inscrutable wrote:

"if the amplifier has a very large - let’s say infinite - current capability, so can maintain voltage to be applied as the speakers impedance changes with signal frequency changes …?"

A constant-voltage amplifier will put out reduced wattage into a higher impedance.  That's just the way that type of amplifier behaves. 

However a constant-power amplifier will put out essentially the same wattage into the speaker's impedance even as it changes, at least within a realistic range of change. 

Most tube amplifiers have a constant-power characteristic, and therefore the system's dynamic contrast would be less sensitive to heat-induced changes in the drivers' impedances. 

Duke

Thanks Duke, that might explain why I really like tube amps feeding high efficiency speakers.  Most of the tube types I like don’t put out much power.  I like 45 and 2a3 in SET amps and 6L6 and KT 66 for push pull amps.  In my own amp that is currently in my system, I run 349s—two per channel for about 5 watts.

@inscrutable

If you are basing that off so called dynamic range databases, keep in mind that dynamic range may be based on a "time period", not instantaneous (well fraction of seconds - second) dynamic range. In a given frequency range, I would expect that to be even more the case. My understanding of it is that it shows peak to average of a given time period, not peak to minimum which would be more critical to this discussion though perhaps both are.

I know many here hate ASR, but it would be good to collectively push them to do more frequency response measurements at varied power levels, and perhaps at different frequency sweep speeds to induce this issue. I personally don't see Stereophile doing that and I definitely don't see suppliers going out of there way to highlight problems.

If you like to Rock Out....Hi Eff. Speakers like Tekton...Klipsch and JBL are BOSS Baby........Low eff. speakers for Bach but not for Rock !

A 110db horn running off 20 watts will not see any heat that can cause compression a 86db speaker requiring over 250 watts will be near melting at peak SPL levels. A horn also has better throw so at distance, its SPL level isn't dropping as fast as a standard dynamic speaker design. Standard dynamic designs can sound pretty darn nice but they are toys when compared to a proper large horn speaker. Now I know most cant house anything over a toaster-sized box or overly slim tower and they don't want to consider that larger is better even though the brand of small boxes they bought most likely has a much larger model as the top of the line.