Dynamic compression in speakers themselves?


The primary audio characteristics I want to achieve in my system is an open, uncompressed, unstrained, and highly dynamic presentation.  What I don't know much about is how much speakers can or do contribute to loss of dynamics and impact.  I have a very powerful amp, but it seems that when I increase the volume, yes, the speakers get louder, but perhaps not commensurate with the increase in the volume control.  I do think I understand that this type of presentation is more easily achieved with larger scale speakers, but even with my large speakers, I feel something is wanting. 

I guess my question is, what factors contribute to any compression occurring in the speakers themselves?  Also, can the age of a speaker cause a loss of dynamics?  Mine are ~20 years old.  I'm thinking to get new speakers in the foreseeable future, so I'd like to understand more about this.  This question is in regard to traditional dynamic speakers.
mtrot
Your experiencing thermal compression 1 reason why so many audiophiles tend to use systems sparingly or for short sessions for with longer playing time VC heating and compression can cause listener fatigue. Its the price audiophiles pay for running undersized loudspeakers that require massive power to produce SPL 
The primary audio characteristics I want to achieve in my system is an open, uncompressed, unstrained, and highly dynamic presentation.           A horn does all this a more and can run off low power thus very little thermal compression.                                                                   Hoffman’s Iron Laws of Speaker Building

1) Bass Extension

2) Efficiency

3) Small Enclosure

The law is that you can only have two of these three attributes in speaker building.  Ideally we would want all three, we want speakers with good bass, can play really loud, and are small.  Unfortunately we cannot have all these.


@johnk

Interesting.  I generally am drawn to big speakers with big woofers, for the same reasons you articulate, lol.  My current, quite large, Legacy Audio Signature II speakers are from the 1990's, but still sound decent at moderate levels.  It's just that I wonder how good the capacitors and other components still are, or ever were in the first place, and how much limitation in dynamics these speakers may have.  I feel that understanding more about this issue will be of use to me when considering future speaker purchases. 
Oil caps can fail at about 20 years of age so you may have a wee bit of change in crossover values. Crossover parts have made advancements in materials  sound quality but not innovation. Honestly if your looking to upgrade it maybe time to do so. Or if skilled you could pull networks build a modern version and compare against originals to see and or measure any difference.  A improved network may offer a good level of improvement or it may not you only really know if you can compare to original many just mod stock networks say it sounds great now but never compare mods to stock thus you do not know if its confirmation bias that is in effect  or actual improvements.
Yes your speakers very much so have major liabilities being that old and not rebuilt most everything is limited 
capacitorsfor sure wear out ,and most likely  real crap 
electrolytics in there which should not even be there resistors also .  Which just  this alone would totally rob the system of fidelity and dynamics . If the amp too is old  rebuild it capacitors , resistors 
wiring ,all can be be drastically improved 20 years ,even 15 years capacitors are known to leak ,or dry out  . I have been through 
this in the past ? First decide do you want solid state ,or Vacuum Tube, that will determine  how efficient your Loudspeakers need to be ,and how Loudin SPL levels you need ,and room size how far away you sit.  How powerful the Bass , or maybe a great monitor 
with excellent subwoofer-s.  Many options , your $$ budget will 
determine this ,how about preamp, or integrated ?