Two terms I don't understand - please explain


Hello...

I've read through this forum as well as forums on other sites and there are two (2) terms that I don't understand: "Slam" and "Prat" when discussing turntables, cartridges, etc.

Could someone kindly explain to this idiot what they actually describe?

Thanks and regards,

Jan
jsmoller
Jan, most often slam refers to bass impact. That is you feel the sound waves hitting you rather than just hear the notes being played.

PRAT refers to Pace Rhythm And Timing. This applies to all playback media not just analogue . If a system has poor PRAT it appears slow and lifeless. Good PRAT means that it is alive much as the real event would be.

I will leave to others with more knowledge than I have to explain why we perceive something as having good PRAT.
Slam = dynamic impact, i.e., how well loud, fast extreme transients are rendered.

Prat (or PRaT) = Pace, Rhythm and Timing -- a component with PRaT gets your toes tapping, let's you hear an feel the drive and pulse of a tune (maybe even puts it there, in some cases, e.g., where a TT spins too fast). Pretty much the same thing as boogie factor.

Roughly, anyway.
Phaser's explanation of slam is better than mine. It refers specifically to bass transients.
Pace, Rhythm and Timing are nice, but I'll take Noilly Prat any day--it mixes well with gin at about 1 to 8 and makes everything sound better. ;)
Great explainations of the generally accepted interpretations of these terms; however, I'd like to point out that the Pace, Rhythm and Timing part of PRaT are misnomers. All but the most seriously flawed systems get these elements of sound reproduction correct.

All but the most grossly out of whack turntable will get pacing (tempo) right. If pacing is right, then rhythm and timing (another word for rhythm) are right.

So what leads to this impresion of better PRaT for one system vs. another, it's the ability to effortlessly reproduce dynamic range, from the very softest to the very loudest, without introducing other undesireable elements (distortion).

I'm a serious musician and we often use dynamics and accents to imply speed and motion. If you don't hear the dynamic change, then the music sounds, lifeless and uninvolving.

PRaT and Slam are the same, IMHO, except that Slam refers to bass dynamic performance.

PRaT seems to be a permanent part of our lexicon, but I think misunderstanding it might do more harm than good. I'd like to see it banished, but I'm only one vote.

In those instances where Pace is flawed, it's usually the fault of the TT or the TT's power supply variability, causing wow and flutter or speed inaccuracy. Guess what, when you fix these things you get better "slam". Applying this to other components, where electrons flow in nanoseconds is folly, IMHO.

DAve
Dcstep. I disagree that every TT that's not "grossly" out of whack gets pace right. I don't think belt drives in general do. My Lenco does, though. Also, poor speakers or badly matched speakers and amp can be sluggish.
I too disagree with Dcstep about PRaT. IMO it is more about subtle micro dynamic shading- even within a single note/chord as it is played. Slam is only the leading edge of the note, when you feel the kick drum hit your chest concisely for instance...
04-29-08: 4est said:
"I too disagree with Dcstep about PRaT. IMO it is more about subtle micro dynamic shading- even within a single note/chord as it is played. Slam is only the leading edge of the note, when you feel the kick drum hit your chest concisely for instance..."

Hmm, I agree with everything that you say here, so I'm wondering in what regard do we disagree. I think that PRaT is really about dynamics, as you said.

Dave
04-29-08: Rnm4 said:
"Dcstep. I disagree that every TT that's not "grossly" out of whack gets pace right. I don't think belt drives in general do. My Lenco does, though. Also, poor speakers or badly matched speakers and amp can be sluggish."

We certainly do disagree about belt drive TTs.

Now how does a bad speaker/amp mismatech impact either Pace, Rhythm or Timing? "Sluggish" maybe, but Pace, Rhythm or Timing, I don't see how.

I've heard bad speaker/amp matches manifest themselves mainly in the bass region, where a speaker needs more control and the amp can't provide it, resulting win woolly, bloomy, over ripe bass. (Nothing to do with Pace, Rhythm or Timing). I've also heard an bright amp matched with a speaker with very extended highs, resulting in a bright, etched, unpleasant treble. (Again having nothing to do with Pace, Rhythm or Timing).

I'm trying to get people to focus on the words "Pace", "Rhythm" and "Timing" and not use them to describe something that's not happening.

Dave
I agree more so with Rmn4's original description of slam, it is not so frequency related as stated. What about a rim shot? That is not bass but it's all about speed and dynamics. I also do not agree with Dcstep on the prat. I can name components that do not time very well but I risk offending people with them that are happy, for what?
Maybe you could name an vintage component that doesn't "time very well".

Lot's of times there is intermodulation distortion between the two-speakers (don't even talk about surround) and between the speakers and the room. IM distortion can make a system seem harsh and/or muddy and/or confused. Technically it IS a timing music, but has no impact on the pace and rhythm of the music.

Dave
Thanks PPL. Interesting answers. So, slam would be the "attack" of the notes or drumbeats and prat would be how closely the music adheres to timing, ie. 4:4, 3:4 time, etc.?

Regards,

Jan
04-29-08: Jsmoller said:
"...prat would be how closely the music adheres to timing, ie. 4:4, 3:4 time, etc.?"

I can't wait to hear the answer. ;-)

Dave
If your drivers aren't well controlled by the amp, they will sound blurry at the edges of the note (well, through the whole note) and that will give you a PRaT issue. Woolly bass is fuzzy arounf the edges, and is certainly not PRaTty bass. Just when do you tap that toe?

Belt drives can be wonderful. No denying it. I learned about PRaT from a Naim driven Rega Planar 2. Actually, my Naim Nait 3 was pratty with all sources, in a way previous amps were not, and in which my NAP140/NAC32.5 is, but my Scott 222c and Sherwood AM-7040 are not -- though I don't think that's a flaw in these latter, as I think Naim are (or were) designed with highlighting the prat-making bits of signal. Hey, it works, and is extremely exciting. As I said in my earlier post, PRaT can be introduced into a signal.

Anyway, I was quite happy with various belt drive TT's until I heard a Lenco.
Another view............

I think PRaT is difference between listening to music and listening to HiFi.
One gets your toes tapping and other gets you admire the equipment.
04-29-08: Rnm4 said:
"...Actually, my Naim Nait 3 was pratty with all sources, in a way previous amps were not, and in which my NAP140/NAC32.5 is, but my Scott 222c and Sherwood AM-7040 are not -- though I don't think that's a flaw in these latter, as I think Naim are (or were) designed with highlighting the prat-making bits of signal. Hey, it works, and is extremely exciting. As I said in my earlier post, PRaT can be introduced into a signal..."

Please explain how an amp alters either Pace, Rhythm or Time.

Dave
I thought "slam" referred to midbass energy, and "PRaT" to speed stability. Clock jitter in a digital source affects PRaT, so that when you try to tap your toe to a jittery player you keep losing the beat. It's a weird experience the first time you notice it.
I'm really curious about those of us not able to tap their toes with a CD player. I have tons of play-along CDs from Music Minus One and Jamey Aebersold and this has never happened to me. What are some CDPs that that will exhibit this problem? I'd like to find one to see what you guys are talking about.

Dave
"Please explain how an amp alters either Pace, Rhythm or Time."

Thought I did that, to an extent. Another shot: having microdynamics that do not slur attack and decay.

But I'm no electrical engineer, so won't pretend to play that game.

Anyway, some amps -- Naim in particular -- are famous for having PRaT, and are even (with Linn Sondeks) the source of the whole concept. I think what PRaT refers to is essentially pegged to whatever it is they do that people identified in the sound and called "PRaT. Not sure what it exactly is, or what they do that accounts for it, but whatever it is, it's PRaT", and Naim amps do it. Krells and CJs, in comparison, I gather, don't.
04-29-08: Rnm4 said:
""Please explain how an amp alters either Pace, Rhythm or Time."

Thought I did that, to an extent. Another shot: having microdynamics that do not slur attack and decay."

Ok, so we agree, it's about dynamics, not Pace or Rhythm or Time, right? That's my whole point. People call it PRaT when it's really dynamics.

Dave
Well, transient response too; but I don't think you can fully distinguish transient response from dynamics. Anyway, nobody ever said PRaT was reducible to any one separable factor. It's more complex than that. So the fact that it clearly has to do with dynamics and isn't clearly exactly one other thing doesn't mean it's just dynamics.
I'm not picking on you, really, but what's "transient response" and how does it relate to either Pace, Rhythm or Timing?

Hint, I think that transient response has more to do with the shape of an acute wave and not timing.

Remember, I believe that PRaT is a misnomer. The perception has more to do with the system's ability to produce dynamics (micro and macro) rather than anything to do with Pace, Rhythm or Timing. (The rhythem one borders on rediculous).

Dave
Well, you keep asserting that. I don't see a host of folkks rushing to agree.

You think the shape of the wave will not effect timing? The wave is IN TIME, no? Not that that proves anything, but the idea that blurred attacks and decays -- and different degrees of blur at at different frequencies -- cannot effect perceived timing pace and rhythm is not at all ridiculous.
I only want to see those terms banned in audio discussion, especially in professional reviews, just because they've become lazy cliches. They've become shorthands for the times when the reviewers need crutches. How many times have you read a review that had some reviewer saying great slam or great prat, and at the end, had no fricking idea how the component actually sounded? Too many, at least in my experience. A part of the reason why you can't take some of these reviewers too seriously as legitimate critics.
Well Rnm4, a blurred attack is better described as a blurred attach, not something to do with PRaT. That's my point.

I like Caspermao's assertion, that PRaT is just a lazy cliche. I add that it never made sense as an acronym in the first place because the word in the acronym don't match the attributes trying to be described.

Dave
So when we were all hanging out and boogieing to a transistor radio did that have prat?
Dcstep, I have a Magnasonic DVD player that loses the beat. A pal has an old Pioneer changer that's even worse. From reviews that appeared in UHF Magazine long before I bought my first CDP (in 1999), the phenomenon was more widespread and farther up the scale in the early days.
When attacks and decays are not accurate, the music *will* lose "pace, rhythm, and timing." So in that sense I do believe the acronym makes at least enough sense to be used. PRaT also sounds a little cooler than something like AAAD (accurate attacks and decays). Can anyone think of any other ones to use?

"That CDP has PRaT" is a bit easier to say than "That CDP is very good at not blurring attacks and decays." It's just a way to generalize. Some acronyms just exist, and while they may not be perfect, they've become the generally accepted way to refer to something.

So I guess what I'm saying is, I think a lot of us are going to continue to be "lazy" and "cliched" and just say "PRaT."
04-30-08: Tobias said:
"Dcstep, I have a Magnasonic DVD player that loses the beat. A pal has an old Pioneer changer that's even worse. From reviews that appeared in UHF Magazine long before I bought my first CDP (in 1999), the phenomenon was more widespread and farther up the scale in the early days."

I've never heard of this, but I assume it must be true since you say so, however I wouldn't describe that as a lack of PRaT, but that the CDP was a worthless POS that no one should consider. I've only been in digital since the late 1970s and never witnessed a CDP skipping a beat, so that's a new one on me.

Dave
04-30-08: Jwglista said:
"When attacks and decays are not accurate, the music *will* lose "pace, rhythm, and timing.""

Please explain how. You're talking about the shape of the wave, not the timing.

Use musical terms. In music, pace means speed, rhythm means the timing between notes and timing means much the same thing. I've NEVER heard any electronic component impact that, with the exception of a very bad TT, with lots of wow and flutter.

Dave
Well as I said, PRaT is not a direct reference to the physical effects of a loss of accurate attacks and decays. Rather, it is a perception of rhythm and timing loss. You have to think outside the box a little bit here.

I believe that from the entire acronym, "rhythm" is the most appropriate descriptor, because the rhythm of a song is perceived as being inaccurate or unmoving when the attacks and decays are not reproduced in their original form. I guess that applies to the entire waveform as well.

But in the end, I think "PRaT" is mostly used to describe something like the "toe tapping factor" (which sounds a lot dumber than PRaT). If it's music that gets you involved, get's you bobbing your head, tapping your toes, whatever, then the music has "PRaT." As far as physics go, I believe that music that lacks this quality has poor reproduction of dynamics, and a huge part of the sound of dynamics is attacks and decays. You can argue that the term is stupid, I really don't care. I don't use it that much anyhow. But at least when someone uses it, I know what they're *trying* to refer to. :)
Jwglista, I think we agree. I think it's unfortunate that someone coined this phrase and it came into widespread usage. It just confuses many, like our good OP on this thread, and perpetuates the widespread belief that audiophiles are a bunch of tweaks that don't know what they're talking about.

Oh well, windmill wins again...

Dave
"and perpetuates the widespread belief that audiophiles are a bunch of tweaks that don't know what they're talking about."

would that be the part about belt drives not having prat or dvd players that lose the beat?
No further comment... ;-)
JUST FYI- Martin Colloms(Who happens to have an Electro-Acoustics Engineering Degree, as they call them in England, has authored a number of AES papers and books on speaker design,etc) is credited with coining the term, "pace". Here are his views on the topic: (http://www.hificritic.com/downloads/Archive_A7.pdf)
Rodman, thanks for the great link. I think almost all the PRaT or Pace attributes come down to either Timing (as defined in that article) and Dynamics. This still leaves me uncomfortable with either term. It's interesting that neither "Pace" or "PRaT" include a letter for dynamics. That article talks a good bit about the importance of dynamics.

His definition of Timing was particularly lucid and really dealt with the issue of how micro timing sometimes doesn't come thru. The example of the bass player being ahead of the beat (the good ones actually do that by training in certain circumstances) and the inability of a couple of CDPs to reproduce that was right on point.

Dave
I figured I'd let the dust settle B4 letting the originator define his own terms(more fun that way). Happy toe-tapping!
I just very casually scanned the article from Martin Collins, and at least on that scant basis it seems clear to me that he does not vindicate at all Dcstep's claim that PRaT is a misnomer for dynamics, and that all decent gear has it. Quite the contrary. Quite.
Misnomer for dynamics and timing (as defined by Collins).

I recommend to all to stop using terms that you can't explain in specific terms.
Dynamics AND timing. Big difference from Dynamics alone.
Yeah, but nothing to do with rhythm and pace. Also, it no one here described timing accurately at all. An acronymn that's only 1/3d right is pretty misleading, IMHO.

Dave
A "prat" is convinced he has better hearing and a far more resolving system than others. The normal "prat" behaviour is to "slam" inferiors with little explanation or constructive advice other than anecodotes. If you don't get it then you are either deaf or don't have a "resolving system". Typical manifestation is a preference for extremely expensiove boutique brands, totally inexplicable phenomena and a snobbish condescending attitude to any conventional consumer gear as being woefully inadequate. If a component is cheap then it can't possibly be any good.

Occasionally "prats" will band together unanimously and bash a successful consumer audio company like Bose - this is called a "Grand Slam".

Most audiophiles are real "prats", and of course I include myself among this esteemed group!!! ;-)