Bruce is 100% Correct! Speakers are linear devices, their performance does not change with amplitude (volume) until they reach their thermal or mechanical limits. What does change is our own hearing, and this has been well documented starting with Fletcher Munson curves.
The ELX are considerably more dynamic speakers than our bookshelf speakers, they also produce much deeper bass extension. They are also considerably cleaner with lower levels of distortion at the same volume levels. This "cleaner sound" does generally lead listeners to listen at higher volume levels than previously.
A few important questions:
How are you measuring what SPL you are listening at?
Are you using a subwoofer in this room?
What is your listening distance from the distance?
Thanks in advance!