What exactly is PRaT???

OP…. As the old line goes about jazz… Of you have to ask, you’ll never know….

To me, PRaT is a subjective (although not stupid) term.  To me, it refers to how realistic the music sounds, i.e., does it sound like you are there?  Does it give the illusion of a performance right in front of you, with depth, width and proper tone?  Since that is so dependent upon system, synergy, room size and treatment, etc., it can only be subjective.  I never refer to PRaT for that reason — I just say that my system makes me feel that I am there witnessing the performance, wide and deep soundstage, etc.  Those are terms that although they are subjective, they have some general understanding among the audiophile community.

It means the music is vibrant & the musicians are playing together. So the meaning of the song comes through. 

@soix 

I thought I understood the concept to mean musical pace, rhythm and timing.  However I have come to think of it as more than that- explanation in a minute. 

A system with a lack of PRAT sounds mono level- at a micro dynamic level, minor swings in volume, not opposed to big swings in level which is different- meaning all sounds tend to be banded together in a limited micro bandwidth and when listening tends to sound flat and unexciting, like the music just sits there by comparison.  

However once I acquired fast speakers and a fast class A amplifier PRAT took on a whole new meaning for me.  It was no longer just about rapid transitions in micro dynamics, it also became about musical element separation and audible distinction.  Musical elements became much more on their own in space, relative volume level and distinction / clarity.  It was as if each voice or instrument had its own physical channel and speaker.  Everything stood out more on its own and quite amazing.  The music and sound had much more contrast which let the pace and rhythm of each instrument become clearly audible.  A drum track in the background was much easier to follow and focus on because it was much more delineated than with a less dynamically capable system which seemed to blend everything together.  

@bryhifi 

Great comments. I never thought of it that way. Good analogy. 
 

I just want to point out again that PRaT is probably the most difficult parameter to sense. I know many folks that do not know how to detect it yet. But with thought and careful listening you probably will eventually. And that is likely to be a real epiphany.