Karen Sumner

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One way to advocate and educate for adopting the sound of live music as a reference for a stereo system is to take the approach Karen and others are taking by discussing characteristics of live and reproduced sound. In the opening post there is a synopsis of prior discussions about tonality and dynamics as a lead in to discussing the use and effect of space as an important aspect of what and how we hear.

While it is important to have counter-examples -- stuff that is sonically artificial -- most important, imo, is to positively encourage what is valued in the sound of live music and encourage these values as goals for reproduction.
On my system, I can often hear the ‘space’ of the venue even before the music starts. If I were to use an alternative word for that perception of ‘space’ I would pick ‘ambiance’ or atmosphere. Ambience is space filling and has dimension and texture. The musicians‘ music interacts with the ambience and is altered by it tonally. For me, presence is the degree to which I sense the presence of musicians within the venue. The reason I would differentiate the two is that they vary independently of one another, depending on how the sound engineer miked and captured the musical event. Studio recordings often include a lot of artificial space or ambience but are not recordings I would categorise as having a lot of presence.
For me the term space is a characteristic of the recording of the venue, while presence is a characteristic of the recording of the performers within that venue.
Perhaps systems that communicate temporal components more truthfully lead us to a better sense of the real. If tone, timbre and presence buy us a sense of instrumental naturalness then temporal truths feed across also into a sense of the real energy of a performance.

I do get the concept of pace… in music it is as Tima has described and the beat and meter of the music and then in terms of how our systems then relate that to us is as you have said our perception of that pace… but like so many words sitting there singular, raw, naked it only says so much and alone the word of itself is just for me an ok communicator. As a term it needs fleshing out and good full supporting context to communicate much.
As someone who tries to be (at least) partially careful about using words in audio descriptions, I am biased toward choosing words that describe what I hear rather than adopting or creating a specialized vocabulary, especially if that brings the need to unpack or explain it in order to inform the reader what it means.
Audio is and always has been system based. Audiophiles generally downplay the importance of room and set up and IMO this is why many are never happy. Its not about the beauty , or the color, or the symmetry of the room its about the nuts and bolts, inches and millimeters, the proper placement of the speakers and the equipment and where you sit. Our rooms will never be "symphony hall" because we can't afford to buy a symphony hall. We strive to create the illusion that you are in that space.
While I have not heard as many systems as you I agree that the vast majority of audiophiles are stuck on the merry-go-round. Why? I think there are a few reasons.

One is that dealers are trying to make money selling boxes. They do this by telling their unsuspecting clients that the next latest, greatest thing is going to move their sound in a positive direction and get them closer to audio nirvana.

Another is that the vast majority of audiophiles don't know how to take what they have and set it up to give convincing results in dynamics, tone & timing. This goes for most dealers whose idea of setup is (maybe) delivering the speakers, unboxing them and maybe getting a centered vocalist.

For some, it may be that they are just playing around like buying the newest golf club.
Hence the only conclusion I can draw is that the space one hears in the recording has microphone choice and placement as the key determinants rather than the sound you hear in the hall which is primarily seat dependent. That’s why I think the discussion of “space” we hear on a recording is largely contrived in many ways. That said, many recordings do capture the hall with some versimultude of the real thing. It’s why the recordings of Cozart/Fine, Lewis Layton, Ken Wilkerson and others are as treasured as they are. But even then, you have to realize that the mics are often 10+feet higher than the stage and often much further forward than the front row of the orchestra. And there are no real seats in those locations! I hope this puts our discussion of recorded “space” into a more realistic perspective. Our sense of space on recordings is mainly attributed to the recording engineer’s skill and preferences and is hardly the same thing as what we hear in the hall in an actual seat, although sometimes we get lucky and are rewarded with a fine listening experience of the recorded event in our home systems.
Pinpoint does not mean small dimension or etched. Pinpoint means you can locate the relative positions of the musicians and layers with accuracy in the soundstage in the sound reproduction, trying to approach the perception you have sighted in a concert hall. Pinpoint means that if the musician is moving in the soundstage you can feel him moving.
I think through gear selection and set up approach, people can choose to create a system presentation that is either more like what we hear from a live concert or more full of audiophile sonic attributes. It is a matter of listener preference, goals, and choices, but people starting out need some kind of guidance.

The industry is good at differentiating between products but perhaps not so good at making the connection between how gear selection and set up can bring one closer to the experience of listening to live music.

The reviews are all about how one box sounds different from another box. My local dealer hands me a glass tablet and leaves me alone in the room to push buttons and listen to different sounds. He then tries to sell me accessories.

No wonder people are confused.
Unless people understand that the objective of sound reproduction is much more than just the enjoyment of people looking for resemblance with their own experience listening to live music they will always get a very limited view of this hobby.
Some of these posts are definitely worth revisiting, and I am sure that some of you have much to add.
 

stehno

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.....

Could someone explain to me what the hi fi use of “rhythm”, “pace”, and “timing” means? I understand what the terms mean when describing different interpretations of the same piece of music. How can these terms apply to the sound of a hi fi system when one can hear the rhythm, pace, and timing of a piece of music on earbuds? What is it about high-end audio systems that make these qualities difficult to identify? Wouldn’t a system that was capable of delivering music with believable tonal balance, instrumental timbres, dynamic range, and space inherently be able to reveal the rhythm, pace, and timing of the music?

.....
Good questions. IMO, experiencing routine PRaT from our in-room playback presentations requires a certain due diligence focused primarily on our playback systems’ much-raised noise floor thresholds and secondarily on a superior acoustic interface between a speaker and its associated room. The very two areas for which our smartphones and computers do not seem to be impacted.

PRaT requires a somewhat catchy / peppy beat, along with a certain speed or quickness, crispness, and/or clarity that results in a greater than anticipated overall dynamic presentation including unanticipated quickness much of which is lost in many a high-end system. Aside from the catchy peppy beat, these and other characteristics suffer greatly from at least one universal distortion plaguing our playback systems that in turn induce a much-raised noise floor threshold. A noise floor that does not seem to impact our smartphones and computers generally or perhaps any impact is negligible.

As of yet, I’m unaware of anybody conversing about much raised noise floors plaguing their portable electronics. Even in my own limited experience, I’m unaware of it being an issue.

I’m also assuming here that we have not-too-dissimilar definitions of PRaT and assuming we’re listening on portable devices with headphones and not earbuds or built-in speakers at the smartphone / computer.

That said, these universal distortions seemingly reserved for high-end audio products will induce a much-raised noise floor threshold. One such ill-effect of a much-raised noise floor is that the rise and fall times of individual notes is slowed…. Well, not actually slowed but so much detail becomes smeared and/or inaudible (cut off?) often times to the point where notes almost seemingly run into each other (less distinct / more monotone) and thus giving the impression that the tempo has slowed. The less distinct each note and beat the less PRaT and vice versa.

PRaT also is elevated somewhat when one establishes a well-defined / musical bass region by generating a superior interface or acoustic coupling between a speaker and its associated room. Again, our headphones plugged into our portable electronics pretty much by-passes this potential weakness as well.

A reasonable similarity might be when every so often a reviewer reviews a component and asks a question like, why does this 3 min 15 sec music track via this component sound slower / faster even though it still takes the exact same 3 min 15 sec to play the exact same track? These kind of issues (distortions) just don’t seem apparent with smartphones or computers and perhaps not with various other portable digital items.

Anyway, below is a demo of what I’d consider an interesting even surprising variation of PRaT - but PRaT nonetheless when volume is up.

 

Karen Sumner

Industry Expert
Apr 18, 2021
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Good questions. IMO, experiencing routine PRaT from our in-room playback presentations requires a certain due diligence focused primarily on our playback systems’ much-raised noise floor thresholds and secondarily on a superior acoustic interface between a speaker and its associated room. The very two areas for which our smartphones and computers do not seem to be impacted.

PRaT requires a somewhat catchy / peppy beat, along with a certain speed or quickness, crispness, and/or clarity that results in a greater than anticipated overall dynamic presentation including unanticipated quickness much of which is lost in many a high-end system. Aside from the catchy peppy beat, these and other characteristics suffer greatly from at least one universal distortion plaguing our playback systems that in turn induce a much-raised noise floor threshold. A noise floor that does not seem to impact our smartphones and computers generally or perhaps any impact is negligible.

As of yet, I’m unaware of anybody conversing about much raised noise floors plaguing their portable electronics. Even in my own limited experience, I’m unaware of it being an issue.

I’m also assuming here that we have not-too-dissimilar definitions of PRaT and assuming we’re listening on portable devices with headphones and not earbuds or built-in speakers at the smartphone / computer.

That said, these universal distortions seemingly reserved for high-end audio products will induce a much-raised noise floor threshold. One such ill-effect of a much-raised noise floor is that the rise and fall times of individual notes is slowed…. Well, not actually slowed but so much detail becomes smeared and/or inaudible (cut off?) often times to the point where notes almost seemingly run into each other (less distinct / more monotone) and thus giving the impression that the tempo has slowed. The less distinct each note and beat the less PRaT and vice versa.

PRaT also is elevated somewhat when one establishes a well-defined / musical bass region by generating a superior interface or acoustic coupling between a speaker and its associated room. Again, our headphones plugged into our portable electronics pretty much by-passes this potential weakness as well.

A reasonable similarity might be when every so often a reviewer reviews a component and asks a question like, why does this 3 min 15 sec music track via this component sound slower / faster even though it still takes the exact same 3 min 15 sec to play the exact same track? These kind of issues (distortions) just don’t seem apparent with smartphones or computers and perhaps not with various other portable digital items.

Anyway, below is a demo of what I’d consider an interesting even surprising variation of PRaT - but PRaT nonetheless when volume is up.

Hi, stehno -

Thank you for explaining the thinking behind PRaT. Although I find the terminology interesting, I question whether it is the best way to explain the psychoacoustic phenomena that you are describing. I think the term seems a bit too metaphorical for all those music lovers who have grown up in the digital world. I think the terminology first appeared not long after compact discs and digital sound were introduced in home audio. PRaT, I think, was in part a way to describe what digital media seemed to be missing. I think the way we perceive pace, rhythm, and timing has a lot to do with how and when music notes initially impact us. One of the stimuli that causes many of us not to feel at ease with early digital sound is the fact that its brick wall filter creates phase shift that is not natural to our ears. The best way I can explain it is that a tone's harmonics lead the fundamental of a tone to a degree that we notice it with our most sensitive of instruments — the ear/brain network. Analog signals, by definition, keep natural phase relationships fully in tact. All parts of the note arrive at the same time. Because the fundamental tone is not in phase with the harmonics, the initial impact of a tone created by a typical 44.1k digital signal is blunted or seems retarded more than it would be if heard live or from an analog source. Our ears are keyed to paying attention to the initial impulse, and if the impulse is not there initially when our ears naturally expect it to be, it is not registered by our minds as being as impactful. The music understandably sounds less compelling than what we have come to expect it to be if our reference is live music or good analog recordings.

Better filtering applied to the aftereffects of the 44.1k brick wall filter is one way to address this. MQA, whether you are a fan or not, is the industry's first attempt to work around this problem. On Tidal you can easily compare native 44.1 digital files with MQA versions. The MQA version to my ears seems to capture more natural fundamental tone and impact. Many audiophiles are vehemently opposed to the MQA approach because they actually have come to prefer somewhat "disembodied" sound, and they even purposely set-up their speakers, as you have noted, to create a more ethereal effect rather than the more earthy presentation that music lovers tend to seek. A preference for "disembodied" sound has been the primary subject of my previous posts.

There is much more to be done in the digital realm to keep everything about a complex music signal where it should be and to remove digital noise artifacts. These are issues which are and will be a particular challenge with most high res digital recordings. That is part of another discussion, however.

Thank you for sharing!
 

Al M.

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Hi, stehno -

Thank you for explaining the thinking behind PRaT. Although I find the terminology interesting, I question whether it is the best way to explain the psychoacoustic phenomena that you are describing. I think the term seems a bit too metaphorical for all those music lovers who have grown up in the digital world. I think the terminology first appeared not long after compact discs and digital sound were introduced in home audio. PRaT, I think, was in part a way to describe what digital media seemed to be missing. I think the way we perceive pace, rhythm, and timing has a lot to do with how and when music notes initially impact us. One of the stimuli that causes many of us not to feel at ease with early digital sound is the fact that its brick wall filter creates phase shift that is not natural to our ears. The best way I can explain it is that a tone's harmonics lead the fundamental of a tone to a degree that we notice it with our most sensitive of instruments — the ear/brain network. Analog signals, by definition, keep natural phase relationships fully in tact. All parts of the note arrive at the same time. Because the fundamental tone is not in phase with the harmonics, the initial impact of a tone created by a typical 44.1k digital signal is blunted or seems retarded more than it would be if heard live or from an analog source. Our ears are keyed to paying attention to the initial impulse, and if the impulse is not there initially when our ears naturally expect it to be, it is not registered by our minds as being as impactful. The music understandably sounds less compelling than what we have come to expect it to be if our reference is live music or good analog recordings.

Better filtering applied to the aftereffects of the 44.1k brick wall filter is one way to address this.

Timing problems in digital are now much less of an issue than they used to be. Even though I have always been particularly sensitive to the issue and have been very critical of deficient rhythm & timing in digital playback, including my own, in the past, I experience my current digital set-up as having excellent rhythm & timing using 44.1k CD playback (to my ears it is as good in that respect as any analog source I personally have heard).

Rhythm & timing problems are also an issue in analog, e.g., from amplifiers and loudspeakers. In the earlier linked 1992 article,


Martin Colloms cites a loudspeaker example:

A neat example of bass rhythm differences is provided by the BBC-designed LS3/5a years ago, This near-field monitor was revised to accommodate a later, more consistent bass unit, while the system's basic, closely toleranced sound was largely preserved. While the new system was generally a little cleaner in the midrange than typical examples of the earlier production, (Footnote 4) rock enthusiasts determined that one other difference had emerged: the older version was found to "time" better, to have more "rhythm."

Searching analysis revealed that the design feature most accountable was the choice of the type of front surround suspension for the bass driver. This had been high-Q, springy Neoprene in the old type, but became a low- Q, absorptive vinyl composite for the new. The latter had been specifically chosen for its loss factor to improve the cone's midrange termination, successfully linearising the response, but apparrently at the significant expense of the speed and fluidity of bass lines. The latter quality appears to rely on the principle of a linear spring, with simple pistonic motion uncomplicated by delay or hysteresis effects.
 
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Al M.

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Analog signals, by definition, keep natural phase relationships fully in tact. All parts of the note arrive at the same time.

That depends, see above loudspeaker example.

Because the fundamental tone is not in phase with the harmonics, the initial impact of a tone created by a typical 44.1k digital signal is blunted or seems retarded more than it would be if heard live or from an analog source.

Not really. If anything, unnatural softening of transient attack seems more of a problem in some analog playback -- and some mediocre vinyl pressings.

Of course, you can have artificial hardening of transients as well, but that is a separate story.
 
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microstrip

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(...) PRaT, I think, was in part a way to describe what digital media seemed to be missing. I think the way we perceive pace, rhythm, and timing has a lot to do with how and when music notes initially impact us.(...)

In fact PRaT comes from much before - as far as I remember it was associated with the Linn Sondeck turntable / Naim system type of sound reproduction. My first exposition to such systems was in London in the very early 80's at KjLeisureSound in Wigmore Street - a complete Linn Sondeck Naim active Linn Isobaric system. At that time there was something magic in that sound for me and I surely owned the Linn Sondeck. Later I also got the anti-PRaT's, such as the Oracle and the Pink Triangle turntable.

As far as I remember, Martin Colloms, the known reviewer that deeply addressed PRaT, owns a current Linn Sondeck turntable.
 
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bonzo75

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In fact PRaT comes from much before - as far as I remember it was associated with the Linn Sondeck turntable / Naim system type of sound reproduction. My first exposition to such systems was in London in the very early 80's at KjLeisureSound in Wigmore Street - a complete Linn Sondeck Naim active Linn Isobaric system. At that time there was something magic in that sound for me and I surely owned the Linn Sondeck. Later I also got the anti-PRaT's, such as the Oracle and the Pink Triangle turntable.

As far as I remember, Martin Colloms, the known reviewer that deeply addressed PRaT, owns a current Linn Sondeck turntable.

Pink triangle is a great value table
 

Al M.

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In fact PRaT comes from much before - as far as I remember it was associated with the Linn Sondeck turntable / Naim system type of sound reproduction. My first exposition to such systems was in London in the very early 80's at KjLeisureSound in Wigmore Street - a complete Linn Sondeck Naim active Linn Isobaric system. At that time there was something magic in that sound for me and I surely owned the Linn Sondeck. Later I also got the anti-PRaT's, such as the Oracle and the Pink Triangle turntable.

As far as I remember, Martin Colloms, the known reviewer that deeply addressed PRaT, owns a current Linn Sondeck turntable.

Yes, PRaT was big also in the Netherlands with the Linn turntable background. At my local dealer back then, around 1990, there were many customers with a Linn Sondek turntable and who liked pop/rock, and most of those who wanted digital chose a Marantz CD80 despite its harsh highs, because at that time it was the player that came closest to the turntable in PRaT. Peter van Willenswaard in the accompanying article to that of Martin Colloms (also in above pdf link) mentions the CD80 for its PRaT capabilities as well. I am sure many of those with the Linn turntable fell in love with its PRaT before digital, as you found magic with it in the early 80s.
 

dcathro

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Yes, PRaT was big also in the Netherlands with the Linn turntable background. At my local dealer back then, around 1990, there were many customers with a Linn Sondek turntable and who liked pop/rock, and most of those who wanted digital chose a Marantz CD80 despite its harsh highs, because at that time it was the player that came closest to the turntable in PRaT. Peter van Willenswaard in the accompanying article to that of Martin Colloms (also in above pdf link) mentions the CD80 for its PRaT capabilities as well. I am sure many of those with the Linn turntable fell in love with its PRaT before digital, as you found magic with it in the early 80s.

The Marantz CD80 was the PRAT king of it's generation (the last of the multibit tda1541a players) because it had the superior brushless Hall motor on its transport. However many of the players from that time such as the Marantz CD50 and CD60 and the Arcam Alpha which have the tda1541a DAC and CDM4 transport can be modified to be incredible sounding machines with fantastic PRAT.
 

Chop

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I really enjoy air and 3D soundstaging on a recording. I have been devouring this fascinating thread, written by more erudite & experienced people who for the most part have better systems than me. :) I thought I'd briefly explain a journey in the hope that it adds something.

Intellectually I want a system which best reproduces the illusion of real people playing in space, which means a system needs to reproduce air. For context my problem with my system's development has been the breadth of music I enjoy: depending on my mood I listen to and enjoy everything from string quartets and Bach's Passions to Thin Lizzy and reggae, all on LP. In the interest of reproducing an illusion of reality classical music is generally played with a lower volume setting than the non classical music. I started to recognise from live concerts that live instruments do not sound like recordings.

Here's the thing for someone with a broad taste in music: getting a system to reproduce "air" is very difficult when one recognises its a completely artificial effect for 50% of the music you listen to. And the amount of it varies from recording to recording.
For me that doesn't mean the effect shouldn't be enjoyed though...

Here's my point for this thread: My enjoyment from my system leapt forward when I stopped trying to do things to it to improve air and sound staging. When I ignored "air" and concentrated on trying to improve the reproduction of tonality (across a range of classical instruments) and dynamics two things happened.
A greater micro dynamic range improved the believability of instruments. The macro reproduction of air on a recording improved almost as a side effect of better tonality.
Also, I found the way that air on a recording is portrayed has changed for the better. I noticed it has become less pinpoint and more like reality. Air expands out from an instrument rather than holding that instrument tightly in space in a soundstage.
Anyway, my point is that for me debating or pursuing the reproduction of air is a dead end. Pursue the reproduction of the fundamentals of music and the air happens, if its recorded in the first place.
 

PeterA

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Here's the thing for someone with a broad taste in music: getting a system to reproduce "air" is very difficult when one recognises its a completely artificial effect for 50% of the music you listen to. And the amount of it varies from recording to recording.
For me that doesn't mean the effect shouldn't be enjoyed though...

Here's my point for this thread: My enjoyment from my system leapt forward when I stopped trying to do things to it to improve air and sound staging. When I ignored "air" and concentrated on trying to improve the reproduction of tonality (across a range of classical instruments) and dynamics two things happened.
A greater micro dynamic range improved the believability of instruments. The macro reproduction of air on a recording improved almost as a side effect of better tonality.
Also, I found the way that air on a recording is portrayed has changed for the better. I noticed it has become less pinpoint and more like reality. Air expands out from an instrument rather than holding that instrument tightly in space in a soundstage.
Anyway, my point is that for me debating or pursuing the reproduction of air is a dead end. Pursue the reproduction of the fundamentals of music and the air happens, if its recorded in the first place.

Chop, could you define what you mean by “air”? Is it the impression of the energy created by the playing of the instruments expanding into the space of the listening room? Is it the “space” one imagines between the musicians up on stage? Is it the breath of life one hears when the presentation is especially convincing? Is it the air one hears going through the pipes of an organ or the musician’s breath as he blows his brass or wind instrument? Or is is something different?

If it is any of these things, I agree that it’s quality and perception depends on the recording and the characteristics of the playback system.
 

Chop

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Chop, could you define what you mean by “air”? 1. Is it the impression of the energy created by the playing of the instruments expanding into the space of the listening room? 2. Is it the “space” one imagines between the musicians up on stage? 3. Is it the breath of life one hears when the presentation is especially convincing? 4. Is it the air one hears going through the pipes of an organ or the musician’s breath as he blows his brass or wind instrument? Or is is something different?

If it is any of these things, I agree that it’s quality and perception depends on the recording and the characteristics of the playback system.
Hi Peter

(I added numbering to your post) For me its primarily #1& 2 in your list. For me both add to the "realism" of the event taking place in your room.
I think 3&4 are artefacts of greater detail. What I think I am hearing is that as my systems ability to resolve smaller gradations of dynamics has improved greater detail seems to have been resolved (though that wasn't necessarily my intention) & #3 & 4 have just... improved.

I think the point I didn't make is that my desire is that the recorded acoustic (its air) is reproduced in my room. My aim used to be to create a large soundstage in my room. The two are fundamentally different, with the first one being a lot more realistic!
 
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PeterA

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Thank you Chop. I appreciate your explanation. I am fascinated by the language people use to describe what they hear from audio systems. In this thread we have space, presence, and ambiance being used in similar ways to describe the character of the environment in which the musicians are playing their instruments and how that is presented by an audio system and understood by the listener.

When I visited DDK in Utah he demonstrated for me how a sense of “air” can be created by choices in gear. He inserted a cable in one of his systems that made all the music we listened to have a sense of “air”. I think the cable manipulated the tonal balance by enhancing the high frequencies. There was a sense of sparkle and lightness permeating all the music regardless of recording or genre or setting. The music sounded a bit etheriel, not grounded, not natural. It was a clear effect created by the design of the cable and the way it interacted with the system. I can’t remember specifically what the music was or much about the actual sound, but I was glad when he took out the cable. I could since there were something not quite right to the sound when the effect overlaid the presentation of everything we heard and created the sameness to the sound.

I agree with your desire for a presentation which describes the variable acoustic of each individual recording. That is much more interesting and representative of reality than simply striving for the biggest deepest soundstage possible from everything you play with a similar sounding acoustic environment.
 

tima

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Thank you for explaining the thinking behind PRaT. Although I find the terminology interesting, I question whether it is the best way to explain the psychoacoustic phenomena that you are describing. I think the term seems a bit too metaphorical for all those music lovers who have grown up in the digital world. I think the terminology first appeared not long after compact discs and digital sound were introduced in home audio. PRaT, I think, was in part a way to describe what digital media seemed to be missing. I think the way we perceive pace, rhythm, and timing has a lot to do with how and when music notes initially impact us. One of the stimuli that causes many of us not to feel at ease with early digital sound is the fact that its brick wall filter creates phase shift that is not natural to our ears. The best way I can explain it is that a tone's harmonics lead the fundamental of a tone to a degree that we notice it with our most sensitive of instruments — the ear/brain network. Analog signals, by definition, keep natural phase relationships fully in tact. All parts of the note arrive at the same time. Because the fundamental tone is not in phase with the harmonics, the initial impact of a tone created by a typical 44.1k digital signal is blunted or seems retarded more than it would be if heard live or from an analog source. Our ears are keyed to paying attention to the initial impulse, and if the impulse is not there initially when our ears naturally expect it to be, it is not registered by our minds as being as impactful. The music understandably sounds less compelling than what we have come to expect it to be if our reference is live music or good analog recordings.

Karen - this is a a fascinating - actually brilliant - account of the PRAT notion. That it is a set of sonic music attributes or characterizations identified in virtue of their absence in digital sound or early digital sound.

I've never really understood PRAT beyond the notion of forward momentum or drive, those descriptions being quite adequate for me with no need to invent a special term that begs explaining.

I asked myself where is this PRAT? Is it an account or description of any music be it live or reproduced? It is not in the score. I don't think it is a conductorial directive although a conductor can drive an orchestra in many directions. Typically I do not hear it discussed in conjunction with live music.

The way PRAT is discussed here, it seems to be a characteristic of reproduced music or of a music reproducing system. You and Collums* suggest it is found in analog systems but is an attribute or characterization in "which digital is surprisingly weak" (Colloms). For PRAT enthusiasts it is important in any music - though perhaps subliminal in classical - but critical to certain types of music - Colloms suggests that without PRAT, rock music becomes banal or boring. I don't know if is inherent in music per but, per claims here, it is something music could lose if it is reproduced in a ... how do I say this ... in a PRATless way?

In one of the responses to Colloms essay a responder notes an example of a Paul Simon tune on Graceland (Warner 25447-2), "I Know What I Know". He describes the bass guitar playing "just slightly ahead of the beat, this 'pulling' creating tension." Here, a slight disjunction between a note and the beat. In that example, the PRAT is in the music. Maybe it is a one-off example or maybe it is a common performance technique, but it does not strike me as something that could be disrupted by reproduction.

You offer what I consider a technical explanation - the disjunction of harmonics and fundamental - a phase error results in PRAT's absence or reduction. I wonder how that translates in circuit design? Is it intentional? Where does it come in? During the recording process via ADC - the digital capture to disc or memory? During the conversion from digital to analog - DAC?

Obviously I don't have answers; maybe my questions are wrong-headed. For now, lacking comprehension of PRAT (but still able to tap my toes to a lively tune) I'll continue avoiding it in description.

* Martin Colloms, Pace, Rhythm, & Dynamics, Stereophile November 1992

edit: spelling
 
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dcathro

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Karen - this is a a fascinating - actually brilliant - account of the PRAT notion. That it is a set of sonic music attributes or characterizations identified in virtue of their absence in digital sound or early digital sound.

I've never really understood PRAT beyond the notion of forward momentum or drive, those descriptions being quite adequate for me with no need to invent a special term that begs explaining.

I asked myself where is this PRAT? Is it an account or description of any music be it live or reproduced? It is not in the score. I don't think it is a conductorial directive although a conductor can drive an orchestra in many directions. Typically I do not hear it discussed in conjunction with live music.

The way PRAT is discussed here, it seems to be a characteristic of reproduced music or of a music reproducing system. You and Collums* suggest it is found in analog systems but is an attribute or characterization in "which digital is surprisingly weak" (Collums). For PRAT enthusiasts it is important in any music - though perhaps subliminal in classical - but critical to certain types of music - Collums suggests that without PRAT, rock music becomes banal or boring. I don't know if is inherent in music per but, per claims here, it is something music could lose if it is reproduced in a ... how do I say this ... in a PRATless way?

In one of the responses to Collums essay a responder notes an example of a Paul Simon tune on Graceland (Warner 25447-2), "I Know What I Know". He describes the bass guitar playing "just slightly ahead of the beat, this 'pulling' creating tension." Here, a slight disjunction between a note and the beat. In that example, the PRAT is in the music. Maybe it is a one-off example or maybe it is a common performance technique, but it does not strike me as something that could be disrupted by reproduction.

You offer what I consider a technical explanation - the disjunction of harmonics and fundamental - a phase error results in PRAT's absence or reduction. I wonder how that translates in circuit design? Is it intentional? Where does it come in? During the recording process via ADC - the digital capture to disc or memory? During the conversion from digital to analog - DAC?

Obviously I don't have answers; maybe my questions are wrong-headed. For now, lacking comprehension of PRAT (but still able to tap my toes to a lively tune) I'll continue avoiding it in description.

* Martin Collums, Pace, Rhythm, & Dynamics, Stereophile November 1992

Hi Tim,

That is Colloms with an O :)

In my experience coming from the British Naim/Linn school of audio, PRAT is in the musical performances to greater and lesser degrees. It is especially evident in pop/rock/jazz, but also in classical. To my mind it is what makes a classical performance/recording special beyond the average.

Reproduction equipment may or may not communicate the PRAt inherent in the recording. If the designer is not aware or listening for it his design may sacrifice it. I am aware of many highly regarded award wining products over the many years that are slow and plodding but have huge detailed soundstages.

My favourite audio quote came from an article by the late Markus Sauer:

"I don't care where they are on the stage, I care WHY they are on the stage"
 

Al M.

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In one of the responses to Colloms essay a responder notes an example of a Paul Simon tune on Graceland (Warner 25447-2), "I Know What I Know". He describes the bass guitar playing "just slightly ahead of the beat, this 'pulling' creating tension." Here, a slight disjunction between a note and the beat. In that example, the PRAT is in the music. Maybe it is a one-off example or maybe it is a common performance technique, but it does not strike me as something that could be disrupted by reproduction.

Until you hear for yourself how PRAT can be disrupted by reproduction, as the author suggests. It definitely can.

Back in the early Nineties, a friend of mine and me often took the beginning of Steely Dan's 'Josie' as a reference for PRAT. The 'swing' upon the entrance of the rhythm section could easily be disrupted -- once, as we incredulously experienced, even by changing an interconnect (!).

With deficient playback it could be made to sound, in the apt words of dcathro above, "slow and plodding".
 

stehno

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Hi, stehno -

Thank you for explaining the thinking behind PRaT. Although I find the terminology interesting, I question whether it is the best way to explain the psychoacoustic phenomena that you are describing. I think the term seems a bit too metaphorical for all those music lovers who have grown up in the digital world. I think the terminology first appeared not long after compact discs and digital sound were introduced in home audio. PRaT, I think, was in part a way to describe what digital media seemed to be missing. I think the way we perceive pace, rhythm, and timing has a lot to do with how and when music notes initially impact us. One of the stimuli that causes many of us not to feel at ease with early digital sound is the fact that its brick wall filter creates phase shift that is not natural to our ears. The best way I can explain it is that a tone's harmonics lead the fundamental of a tone to a degree that we notice it with our most sensitive of instruments — the ear/brain network. Analog signals, by definition, keep natural phase relationships fully in tact. All parts of the note arrive at the same time. Because the fundamental tone is not in phase with the harmonics, the initial impact of a tone created by a typical 44.1k digital signal is blunted or seems retarded more than it would be if heard live or from an analog source. Our ears are keyed to paying attention to the initial impulse, and if the impulse is not there initially when our ears naturally expect it to be, it is not registered by our minds as being as impactful. The music understandably sounds less compelling than what we have come to expect it to be if our reference is live music or good analog recordings.

Better filtering applied to the aftereffects of the 44.1k brick wall filter is one way to address this. MQA, whether you are a fan or not, is the industry's first attempt to work around this problem. On Tidal you can easily compare native 44.1 digital files with MQA versions. The MQA version to my ears seems to capture more natural fundamental tone and impact. Many audiophiles are vehemently opposed to the MQA approach because they actually have come to prefer somewhat "disembodied" sound, and they even purposely set-up their speakers, as you have noted, to create a more ethereal effect rather than the more earthy presentation that music lovers tend to seek. A preference for "disembodied" sound has been the primary subject of my previous posts.

There is much more to be done in the digital realm to keep everything about a complex music signal where it should be and to remove digital noise artifacts. These are issues which are and will be a particular challenge with most high res digital recordings. That is part of another discussion, however.

Thank you for sharing!
You’re quite welcome, Karen. However, I’m confused as I was responding to your questions as to why PRAT can be more easily detected / achieved by smartphones and computer than with many a high-end system and you seemed to entirely ignore perhaps the only sufficient response you may get on this subject.

For the record, PRAT has little/nothing to do with analog vs digital since as I mentioned PRAT is primarily impacted by our playback system’s much-raised noise floors induced by universal distortions. Of course, one good thing about universal distortions is that they don’t discriminate against much of anything. Also as mentioned, to a lesser degree PRAT is also impacted by an acoustic noise floor of sorts induced by our speaker / room interface. Then again, most everything about our playback presentations is impacted by these two independent noise floors. :)

I must say I found your comments about MQA / PRAT rather humorous. Perhaps I overlooked it but in all my numerous readings of MQA or interviews with Bob Stuart I don’t recall a single mention of Stuart intending to specifically address PRAT in his childhood dreams.

Lastly, you said above,

“Many audiophiles are vehemently opposed to the MQA approach because they actually have come to prefer somewhat "disembodied" sound, and they even purposely set-up their speakers, as you have noted, to create a more ethereal effect rather than the more earthy presentation that music lovers tend to seek. A preference for "disembodied" sound has been the primary subject of my previous posts.”

Actually, some of us are just vehemently opposed to MQA’s inferiority and the fact that certain industry “leaders” attempted in the early days to masquerade MQA as a sonically superior format. Especially when to the best of my knowledge the inferior MQA format can do nothing to sufficiently address PRAT or perhaps any sonic characteristic in a positive way. To the contrary, and based on the findings of Peter Moncrieff of IAR, I’ll bet dollars-to-donuts MQA strips away any hope of achieving real PRAT.

But I suspect there are other potential implications with your statement here. FWIW, when I focus specific efforts toward achieving superior or more musical bass, it’s not because I’m seeking some euphonic PRAT to have my ears tickled. Rather, I’m seeking for a quicker, tighter, deeper, more well-defined, and overall more musical bass hopefully in every reasonable regard. PRAT just so happens to be one of several / numerous sonic characteristics observed when such improvements occur. I see it as a cause and effect thing. The more superior the bass regions the more frequent and evident any available PRAT. Sure there may be a few whose sole purpose in their audio life is to focus on PRAT. I’m not one of those.

But when PRAT is abundantly evident, it just so happens the presentation is also that much more abundantly engaging. But that’s also because other numerous sonic characteristics are also more evident. In fact, when a system alteration is made, rarely if ever is just a single sonic characteristic like PRAT improved. Rather, sonic improvements are generally more across the board even though we may only notice or focus on improvements in one or a few more coveted sonic characteristics.

BTW, here’s a slightly less deniable example of PRaT. Provided you’re willing to crank up the volume. You being seemingly an analog fan, you just might even have Jean-Luc Ponty’s Imaginary Voyages album in your library.


p.s. Indeed there is much yet to be done in the digital realm just as there is much yet to be done in the analog realm.
 

stehno

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Timing problems in digital are now much less of an issue than they used to be. Even though I have always been particularly sensitive to the issue and have been very critical of deficient rhythm & timing in digital playback, including my own, in the past, I experience my current digital set-up as having excellent rhythm & timing using 44.1k CD playback (to my ears it is as good in that respect as any analog source I personally have heard).

Rhythm & timing problems are also an issue in analog, e.g., from amplifiers and loudspeakers. In the earlier linked 1992 article,


Martin Colloms cites a loudspeaker example:

A neat example of bass rhythm differences is provided by the BBC-designed LS3/5a years ago, This near-field monitor was revised to accommodate a later, more consistent bass unit, while the system's basic, closely toleranced sound was largely preserved. While the new system was generally a little cleaner in the midrange than typical examples of the earlier production, (Footnote 4) rock enthusiasts determined that one other difference had emerged: the older version was found to "time" better, to have more "rhythm."

Searching analysis revealed that the design feature most accountable was the choice of the type of front surround suspension for the bass driver. This had been high-Q, springy Neoprene in the old type, but became a low- Q, absorptive vinyl composite for the new. The latter had been specifically chosen for its loss factor to improve the cone's midrange termination, successfully linearising the response, but apparrently at the significant expense of the speed and fluidity of bass lines. The latter quality appears to rely on the principle of a linear spring, with simple pistonic motion uncomplicated by delay or hysteresis effects.
Well said, Al. And you providing this article by Colloms was quite beneficial. Thanks.
 

Al M.

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I must say I found your comments about MQA / PRAT rather humorous. Perhaps I overlooked it but in all my numerous readings of MQA or interviews with Bob Stuart I don’t recall a single mention of Stuart intending to specifically address PRAT in his childhood dreams.

Lastly, you said above,

“Many audiophiles are vehemently opposed to the MQA approach because they actually have come to prefer somewhat "disembodied" sound, and they even purposely set-up their speakers, as you have noted, to create a more ethereal effect rather than the more earthy presentation that music lovers tend to seek. A preference for "disembodied" sound has been the primary subject of my previous posts.”

Actually, some of us are just vehemently opposed to MQA’s inferiority and the fact that certain industry “leaders” attempted in the early days to masquerade MQA as a sonically superior format. Especially when to the best of my knowledge the inferior MQA format can do nothing to sufficiently address PRAT or perhaps any sonic characteristic in a positive way. To the contrary, and based on the findings of Peter Moncrieff of IAR, I’ll bet dollars-to-donuts MQA strips away any hope of achieving real PRAT.

Any informed member of the industry should know that MQA is a technical fraud.
 
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