What does the term "Speed" mean in a speaker?


I often hear people say "That speaker has great speed". What do they mean? I know the music isn't playing at a different pitch. Could it possibly be related to efficiency?
koestner
Yep, transient response. I would say decay does not fall under the umbrella of speed or transient response but others may feel differently.

I just received the center channel that matches my Legacy Focus SE L/R Speakers. It mentions "speed" in their advertising also. Here’s part of their Ad


Legacy’s best center channel speaker has been updated to the Marquis XD. Featuring our 4" AMT ribbon, as found in the Legacy Dual Air Motion Tweeter system, and the 8" Italian crafted titanium encrusted midrange as utilized in the Aeris system, Marquis XD is on par with the speed of our best towers. These high precision drivers, a new crossover, and the incredible dual 12" ultra-linear bass drivers with 15 lb motors make it the best center speaker at any price. The dual 12" woofers of the Marquis XD deliver uprecedented linear output with snap and definition with rich upper bass and clean transition to the lower midrange.

Marquis XD can be placed above or below a 60” monitor, or behind a perforated projection screen in your home theater.

Thanks for all of this. Can amplifiers impact/covey speed differently? Seems they play a role as well...from peoples’ reviews. Is that right? 
Thanks!
I agree with simonmoon.  And, yes, I have noticed different amps seemingly add speed.  Again probably due to transients , attack, decay, less bass overhang.  Interestingly, speed hasn’t been something I prioritize but my favorite speakers have it! 
I was going to say the impression of Speed can only be adjusted by Keanu Reeves. But then some snowflake would have that taken down. So instead I will have to seriously explain that since the "impression" of speed nearly everyone equates to high frequencies, that yes boosting the treble a bit can indeed create the impression of speed. A false impression, to be sure. But you said impression, without reference to being true or not.

The truth is an infinitely fast speaker would actually sound LESS noticeably boosted in the treble. Why? Because true speed is not only how fast something gets moving but equally as important, how fast it stops. 

Which in retrospect probably is the best answer. Probably hardly anyone old enough to get the Speed reference anyway.