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What exactly is PRaT???

Ok, it’s like this thing and is associated with “toe tapping” and such.  I confess, I don’t get it.  Apparently companies like Linn and Naim get it, and I don’t and find it a bit frustrating.  What am I missing?  I’m a drummer and am as sensitive as anyone to timing and beats, so why don’t I perceive this PRaT thing that many of you obviously do and prize as it occurs in stereo systems?  When I read many Brit reviews a lot of attention goes to “rhythm” and “timing” and it’s useless to me and I just don’t get it.  If someone can give me a concrete example of what the hell I’m not getting I’d sincerely be most appreciative.  To be clear, enough people I greatly respect consider it a thing so objectively speaking it’s either something I can’t hear or maybe just don’t care about — or both.  Can someone finally define this “thing” for me cause I seriously wanna learn something I clearly don’t know or understand.  

soix
stuartk
2,778 posts
 

@bolong

Master of PRAT ie."swing"

You might check out this analysis, exploring how Little Wing in fact incorporates both straight time and swing, which is why it’s deceptively difficult to get right:

https://www.youtube.com/watch?v=0uGDYs__ZP8

 

panzrwagn's avatar
panzrwagn
519 posts
 

PRaT is experiential, and as such takes some experience to hear - or not hear. It's pretty clear it does not exist in any one domain, like frequency, or phase, per se. The Large Advent is great example - beautifully voiced, extended well controlled bass, but PRaT? Not so much. My explanation is hysteresis - the delay between input and output. Hysteresis may vary due to a lot of factors, amplifier damping, a function of output series resistance, including the amp, speaker cabling, crossover series inductor (one reason internally amplified speakers tend to sound 'quicker') and overall speaker alignment. Acoustic suspension speakers rely on compreesion of trapped cabinet air for damping, and are as a result inherently slower and less linear to stop, resulting in a smear that doesn't show up in frequency response graphs. By comparison, full range drivers, for all their other limitations and freed from those driver control constraints tend to have that ineffable 'liveness' that they are known for.

Likewise, much of the difference between MM, MI, and MC phono carts can be attributed to their inductance, with MM carts having 10X the series inductance - and resulting hysteresis - of most MC carts, with MI like Grado and Soundsmith falling in between. 

As for amplifiers, the ability to control and dissipate the woofers back EMF (the 'brakes') is likely their major contribution to PRaT. 

Overall, I believe PRaT is fundamentally about controlling and minimizing stored energy within a system. It is the release of that stored energy that smears the sound, robbing the music of PRaT.

bolong
602 posts
 

Mechanism of Brain Hysteresis In Human Brain Networks

Cha-cha cha.

mceljo
1,357 posts
 

I agree that PRaT is primarily a subject term that's used to describe a feeling/experience where you find yourself sucked into the music and absent mindedly tapping your toe.  I have experienced it with my system on certain recordings.  From a system perspective, I think that some components tend to excel in the frequencies ranges that can be correlated with the desire to "boogie" so more often bring it out from recordings compared to other components.

bolong
602 posts
 
From a 2021 forum post on the same subject.

 

 
teo_audio
2,197 posts

PRaT, in my book, also has clean delineated ’plosives. part of the package.

It requires a clean start and stop of a transient, with no out of phase smear or lag in the signal additions that are unwanted, which would cover up the fine aspects of the plosive or transient. the requirement is one of a clean wideband low distortion and high signal to noise ratio signal reproduction. That’s what it takes to get a plosive right. Live amplified vs reproduced. the trick is, of course, to get the reproduction to sound like the live and amplified.

When all that is working, we can naturally and natively extract or witness ’PRaT’ in the amplified and reproduced signal..

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