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Perception of Pace/Rhythm/Timing (PRaT) -- genetic?
drewfx
post Jul 5 2011, 16:42
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A simple, non-judgmental question:

If a system can reproduce, without audible distortion, a sine wave oscillating 15 thousand (or more) times per second, why in the world would one believe the same system couldn't reproduce, without audible distortion, musical timings that are probably in the range of 50-100 times greater?

This post has been edited by drewfx: Jul 5 2011, 16:43
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hlloyge
post Jul 5 2011, 18:22
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QUOTE (hollowman @ Jul 5 2011, 14:17) *
I've dug into the issue a bit further and found reporting of it -- using slightly diff. semantics -- not quite as uncommon as I believed. To wit: this info-graphic equipment review style used in the no-longer-pub'd UK audio mag Sonic Boom:


I've recently bought air gun, but hated to draw targets on paper. Can I print this one?
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benski
post Jul 5 2011, 19:21
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QUOTE (drewfx @ Jul 5 2011, 11:42) *
A simple, non-judgmental question:

If a system can reproduce, without audible distortion, a sine wave oscillating 15 thousand (or more) times per second, why in the world would one believe the same system couldn't reproduce, without audible distortion, musical timings that are probably in the range of 50-100 times greater?


I'm going to play devil's advocate here. Two major issues with amplifier and speaker design that could explain this are slew rate and servo feedback. A typical drum hit involves a huge transient that can be effected by the amplifier's slew rate as well as the natural inertia of the woofer's speaker cone. In addition, the "bounce back" of the cone after the initial transient can cause the speaker's motion to diverge heavily from the audio waveform. Self-powered monitors can fix this with servo feedback motors or other mechanisms (flyback transformer?) to give better motion control. I know this is a major problem in electronic injection automotive systems where the injector behaves basically as a miniature subwoofer and the timing of the system can get ruined by the voltage effects of the magnetic driver moving on its own due to inertia and elasticity.

Whether or not this manifests audibly in music equipment is subject to debate, but it does give a plausible rationale for prat effects.

And, again, I'm playing devil's advocate and not actually claiming that speaker elasticity and inertia is going to cause an audible effect except on very bad equipment.
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drewfx
post Jul 5 2011, 19:38
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If these effects were audible, would you expect them to be perceived by the listener as "timing problems" or "distortion" (or both)?

And could they be objectively measured to quantitatively account for a listener's perception of "PRaT"?

This post has been edited by db1989: Jul 5 2011, 21:26
Reason for edit: no point quoting the post at all, never mind in its entirety, when it’s directly above
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Soap
post Jul 5 2011, 19:46
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They should show up as measurable distortion, no?


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benski
post Jul 5 2011, 19:51
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QUOTE (drewfx @ Jul 5 2011, 14:38) *
If these effects were audible, would you expect them to be perceived by the listener as "timing problems" or "distortion" (or both)?

And could they be objectively measured to quantitatively account for a listener's perception of "PRaT"?


They would be both distortion and timing problems. The distortion would occur shortly *after* a drum hit. The timing errors would be a smearing of the transient. As a good way to visualize the problem, find a big woofer on an old speaker set and push it, notice how it has some elasticity to it and goes back to "center" when you let go.

They could be objectively measured quite easily. A simple solution would be to use a high-quality flat-response microphone like Earthworks' "Time Coherent" series or their lab-quality "Measurement" series.

A better solution would be to use some sort of laser/light sensor to record speaker motion and compare it to the audio waveform.

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benski
post Jul 5 2011, 19:53
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QUOTE (Soap @ Jul 5 2011, 14:46) *
They should show up as measurable distortion, no?


Correct, but it's harder to measure when it's the speakers fault (or the interplay between the speaker and the amplifier) versus just measuring the line-level output of a device. And it's a non-linear time-dependent error that would not necessarily manifest itself in traditional speaker frequency-response graphs.

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drewfx
post Jul 5 2011, 20:18
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So then the devil's advocate argument is:

1. The listener would likely perceive both timing and distortion problems.
2. It would be objectively measurable.
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greynol
post Jul 5 2011, 21:16
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QUOTE (hollowman @ Jul 5 2011, 01:11) *
It meant I, FWIW, can sense it in the terms of "hearing it"
This is exactly the meaning of "sensitivity" that I had in mind when responding. At this point I think "imagining" is a much more fitting word than "hearing".

QUOTE (hollowman @ Jul 5 2011, 01:11) *
FWIW, IMO and YMMV
Sorry, this does not absolve you from having to present objective evidence that you actually hear these things.

QUOTE (hollowman @ Jul 5 2011, 01:37) *
pointing to URL link to, say, peer-reviewed, double-blind-controlled counter-evidence.
The burden falls on you to prove your claims, not us to disprove them. Please google "flying spaghetti monster"!

Are you going to present any objective evidence or should I close the topic?


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DonP
post Jul 5 2011, 21:43
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QUOTE (benski @ Jul 5 2011, 13:21) *
[
I'm going to play devil's advocate here. Two major issues with amplifier and speaker design that could explain this are slew rate and servo feedback. A typical drum hit involves a huge transient that can be effected by the amplifier's slew rate as well as the natural inertia of the woofer's speaker cone. In addition, the "bounce back" of the cone after the initial transient can cause the speaker's motion to diverge heavily from the audio waveform. Self-powered monitors can fix this with servo feedback motors or other mechanisms (flyback transformer?) to give better motion control. I know this is a major problem in electronic injection automotive systems where the injector behaves basically as a miniature subwoofer and the timing of the system can get ruined by the voltage effects of the magnetic driver moving on its own due to inertia and elasticity.

Whether or not this manifests audibly in music equipment is subject to debate, but it does give a plausible rationale for prat effects.

And, again, I'm playing devil's advocate and not actually claiming that speaker elasticity and inertia is going to cause an audible effect except on very bad equipment.


In a rational design, a subwoofer (or woofer) isn't supposed to reproduce frequencies outside it's useful range, so with that drum hit, the low frequencies go to the woofer, and the higher frequencies go to the higher frequency drivers. Also recall that a bandwidth limited low frequency signal (like goes to a woofer) mathematically won't be able to precisely represent when the drum hit occurs. That information lies in the higher frequencies.

Faults in how the speaker as a whole handles that (say, a time difference between drivers) or an amp's inability to drive the speaker should be handled by conventional measurements without having to drag fuzzily defined terms into it.

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greynol
post Jul 5 2011, 22:31
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QUOTE (DonP @ Jul 5 2011, 13:43) *
fuzzily defined terms into it.

Thank you!

This is in part why I linked the other thread. As a musician, I'm somewhat disturbed seeing these well defined and accepted terms hijacked by the audiophile community in order to further their dialog of subjective woo.


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knutinh
post Jul 6 2011, 07:23
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1. Find some discussion-forum with a clear profile (e.g. "we demand ABX-tests attached to any claims of audibility").
2. Throw in a lot of words that goes counter to 1. ("I have heard that the bionic flux capacitor stirrs my 30kHz response in a non-measurable fashion")
3. Watch the number of replies rise rapidly. ("Please support your statements", "Audiophool")
4. Ignore all questions and comments and keep injecting the same highly verbose nonsense, now with meaningless charts and graphs.
5. Stand back and enjoy the commotion.

BTW, I am a big fan of generous moderating - even if it means that the occasional troll gets his 5 minutes of fame. Hydrogenaudio would not benefit from being any more of an isolated island of educated, rational, like-minded people than it allready is.

-k

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Nick.C
post Jul 6 2011, 08:22
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Likes ^.

(we need a like button for posts...... smile.gif )


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Notat
post Jul 6 2011, 16:03
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QUOTE (benski @ Jul 5 2011, 12:21) *
I'm going to play devil's advocate here. Two major issues with amplifier and speaker design that could explain this are slew rate and servo feedback.

Maybe add phase response to this. A 90 degree phase shift at 30 Hz is 8 milliseconds. We know that listeners are sensitive to timing changes of this magnitude. Why would they not be able to hear this?
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hollowman
post Jul 8 2011, 13:44
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QUOTE (krabapple @ Jul 5 2011, 07:25) *
What is in dispute is that audio gear has intrinsic qualities that produce different stimuli in the listener for 'pace, rhythm, and timing'. Evidence please. Or at least, explain why your question is any different from 'Is ESP genetic?' Your arguments and pseudoscientific charts so far ring hollow.
For the record:

I am not an "audiophile". I do engage in that community from time to time, via forums, but only to seek answers to certain queries. I'm not in pro-audio or the recording industry. [What is (an) "audiophool"? Is this a pejorative of "audiophile"?] For the most part, I engage in the DIY PC/audio community. (If you want more info on my bg or projects, use SE or feel free to ask, in-lne or via PM)

Ultimately, I have no control as to how you want to charac/label me. You should, of course, weigh the evidence-- accounting for myriad cog. biases, e.g. esc. of commitment -- and come to your own decisions.
greynol ... you asked about keeping this topic open:
I'm working on a more extensive response. It will have some more extensive info ... much in the form of ref. links. But I'm multi-tasking other (non-audio) errands. And need a week or two.
QUOTE
1. Find some discussion-forum with a clear profile (e.g. "we demand ABX-tests attached to any claims of audibility").
2. Throw in a lot of words that goes counter to 1. ("I have heard that the bionic flux capacitor stirrs my 30kHz response in a non-measurable fashion")
3. Watch the number of replies rise rapidly. ("Please support your statements", "Audiophool")
4. Ignore all questions and comments and keep injecting the same highly verbose nonsense, now with meaningless charts and graphs.
5. Stand back and enjoy the commotion.

For the most part, I agree with this.
Can you temp. close it? Or can I continue it -- later -- in a non-Sci Disc sub-forum? IAC, I will accept whatever decision you/forum-body decide.
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db1989
post Jul 8 2011, 13:50
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QUOTE (hollowman @ Jul 8 2011, 13:44) *
greynol ... you asked about keeping this topic open:
I'm working on a more extensive response.
You mean a response that actually addresses the many points of other users, rather than approaching them asymptotically at best? This is what weve all been waiting for!

QUOTE
It will have some more extensive info ... much in the form of ref. links.
Relevant ones, for a change?

QUOTE
Can you temp. close it? Or can I continue it -- later -- in a non-Sci Disc sub-forum? IAC, I will accept whatever decision you/forum-body decide.
For what little its worth, Id be happy to cast my vote for this being closed until you make any effort to defend your assertions directly rather than simply hoping you can drown out opposing views with barely related waffling. But Ill leave the decision to those who have had the energy to attempt to wrestle some sense out of you.
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Woodinville
post Oct 16 2011, 05:02
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QUOTE (greynol @ Jul 5 2011, 14:31) *
This is in part why I linked the other thread. As a musician, I'm somewhat disturbed seeing these well defined and accepted terms hijacked by the audiophile community in order to further their dialog of subjective woo.


Especially since pace, rhythm and timing can be conveyed in a 4kHz bandwidth with a 20dB SNR.



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lbstyling
post Jan 4 2012, 22:10
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QUOTE (Woodinville @ Oct 16 2011, 04:02) *
QUOTE (greynol @ Jul 5 2011, 14:31) *
This is in part why I linked the other thread. As a musician, I'm somewhat disturbed seeing these well defined and accepted terms hijacked by the audiophile community in order to further their dialog of subjective woo.


Especially since pace, rhythm and timing can be conveyed in a 4kHz bandwidth with a 20dB SNR.



Hi,
I joined to post on this.
Prat is something I've taken a interest in for many years, and I have asked many people what is responsible for it. Good prat is reported to be particularly noticeable by its ability to reproduce fast paced music with accuracy, particularly in the bass range. The closest I got to a possible answer is speaker related.

Option 1.
A raised FR around 60hz giving a louder and therefore more prominent band around a kick drum impact


Option 2
Low inductance drivers either for there range (ie a pro sub as opposed to a long throw consumer option) or outright ( as in designing a speaker that rolls off at about 50hz but has a raised response at 60 and will likely include low inductance as a driver feature by default as the design doesn't seek to play low anyway which is what you add inductance for (to extend the LF extension.
Inductance effects the delay of the movement of the driver to the signal, so although a driver will either produce the signal flat or not, it may not start and stop the signal very close to the correct time, amplifier feedback is also related to this (damping factor)

The perception that electronics (amp etc) are responsible for perceived prat is just because the speakers the demoed amp is usually played with is actually the reason for the sound. Good current delivery always helps reinforce the low end too.


A discussion with the designer of 'kudos' speakers confirmed the rather 'British' tuning technique.
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db1989
post Jan 4 2012, 22:39
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Having read a little of the Stereophile article linked, I feel a need to quote these posts:

QUOTE (greynol @ Jul 5 2011, 01:44) *
I truly hope this doesn't end up like it did when Martin Colloms [author of said article—Ed.] came to the forum to puffily interject his two cents on similar matters and then fail to answer any criticism and/or questions posed.
Spoiler: It did.

QUOTE (Soap @ Jul 5 2011, 12:58) *
Mods, can you lock this thread already? OP (hollowman) has thus far refused to directly answer the questions posed of him (despite spending vast amounts of time on the board) and instead continues to use this thread as a dump for a verbose amount of unscientific, unsubstantiated, out of context, and dubious material of questionable merit.

The name of this forum is "Scientific Discussion" and this thread is neither.

QUOTE (greynol @ Jul 5 2011, 20:16) *
Are you going to present any objective evidence or should I close the topic?

Please keep these, and #8 of our Terms of Service, in mind when discussing this supposed phenomenon.

Back to said article, the following excerpt reads like a who’s-who of the things that are to be avoided here (i.e. why TOS #8 exists), in all its wholly unsubstantiated, hopelessly metaphorical, warm-and-fuzzy, utterly nonsensical glory. I’d have thought it was parody had I read it out of context.
QUOTE
For all its quantifiable technical faults, easily identified in the laboratory when compared with the measured near-perfection of CD, the vinyl LP disc possesses a powerful and effortlessly musical content, with an easy, fundamental rhythmic stability and solidity. Interestingly, this innate character seems to be quite robust, more so than digital. [nonsense] Subjectively rewarding results [TOS #8 proscribes subjective methods of evaulation as worthless] may be obtained from analog sources without much trouble. Many well-established but not necessarily high-priced components may be assembled to produce musically satisfying results. With analog, one can listen through the blemishes and be aware of a strong musical message, one in which the music's flow, pace, and tempo are well conveyed, and into which the listener is drawn.

By contrast, digital audio is a fragile medium. Sonic greatness remains elusive, digital replay often seeming to get bogged down at an earlier stage, [what] one in which the listener's lack of involvement leads to a substitute activity. [what] The mind remains busy, but is now cataloguing perceptual features and comparing them with previous experiences. [what] This is an interesting abstraction, comparable in the realm of visual art with the analysis of the brush techniques of old masters. [irrelevant analogy] But, as Robert Harley points out in this month's "As We See It," an obsession with technical minutiae can blind one to an appreciation of the whole. That easy, rhythmic grace inherent in competent analog replay points to one of the greatest paradoxes of digital replay.

Digital's technical advantages at low frequencies include low group delay due to a highly extended bass response, in theory even continuing down to DC. Technical appearances can be misleading, however. From my experience [double-blind tested, I’m sure?] of more than 250 digital products, coherent, expressive, naturally explosive dynamics and the ability to present good musical pace and a confident, upbeat rhythm are areas in which digital is surprisingly weak. If digital bass is agreed to be tighter-sounding, less colored and less "phasey," then how on Earth can analog still be in the running when it comes down to subjectively satisfying bass rhythm? Nevertheless, digital bass generally sounds laid-back and downbeat, even if it is highly neutral when viewed purely in technical terms.
I stopped annotating out of disgust more than anything else, really! What utter nonsense.

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disfrontman
post Jan 5 2012, 03:29
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QUOTE (db1989 @ Jan 4 2012, 16:39) *
QUOTE
For all its quantifiable technical faults, easily identified in the laboratory when compared with the measured near-perfection of CD, the vinyl LP disc possesses a powerful and effortlessly musical content, with an easy, fundamental rhythmic stability and solidity. Interestingly, this innate character seems to be quite robust, more so than digital. [nonsense] Subjectively rewarding results [TOS #8 proscribes subjective methods of evaulation as worthless] may be obtained from analog sources without much trouble. Many well-established but not necessarily high-priced components may be assembled to produce musically satisfying results. With analog, one can listen through the blemishes and be aware of a strong musical message, one in which the music's flow, pace, and tempo are well conveyed, and into which the listener is drawn.

By contrast, digital audio is a fragile medium. Sonic greatness remains elusive, digital replay often seeming to get bogged down at an earlier stage, [what] one in which the listener's lack of involvement leads to a substitute activity. [what] The mind remains busy, but is now cataloguing perceptual features and comparing them with previous experiences. [what] This is an interesting abstraction, comparable in the realm of visual art with the analysis of the brush techniques of old masters. [irrelevant analogy] But, as Robert Harley points out in this month's "As We See It," an obsession with technical minutiae can blind one to an appreciation of the whole. That easy, rhythmic grace inherent in competent analog replay points to one of the greatest paradoxes of digital replay.

Digital's technical advantages at low frequencies include low group delay due to a highly extended bass response, in theory even continuing down to DC. Technical appearances can be misleading, however. From my experience [double-blind tested, I’m sure?] of more than 250 digital products, coherent, expressive, naturally explosive dynamics and the ability to present good musical pace and a confident, upbeat rhythm are areas in which digital is surprisingly weak. If digital bass is agreed to be tighter-sounding, less colored and less "phasey," then how on Earth can analog still be in the running when it comes down to subjectively satisfying bass rhythm? Nevertheless, digital bass generally sounds laid-back and downbeat, even if it is highly neutral when viewed purely in technical terms.
I stopped annotating out of disgust more than anything else, really! What utter nonsense.


FWIW, when I read something like that, it would seem to me that the writer:

a) has to have some stake in denigrating digital audio
(trying to sell or promote a competing product/system? or hoping for kudos from like-minded naysayers?)

or,

b) has listened to analog sound recording playback systems for so long that he/she has grown accustomed and/or fond of said delivery systems inherent quirks (tape hiss, vinyl pops, limitations regarding dynamic range, etc.) and now reads the absence of such elements as "sterile-sounding".

I joined this forum 2 1/2 years ago. I thought all of these pro-vinyl/anti-digital arguments had already been thoroughly debunked when I got here. IIRC, my baptism at HA involved being slapped down for my initial reflections about sample rates/bit depths beyond 44.1k/16 bit. I was set straight by the evidence, and quickly. Seems to me that the claims of die-hard vinyl advocates would be far more of a stretch and far more easily debunked.

I was a quick convert, and I've sent many forum discussions to this site for real facts regarding such issues. Why wouldn't anyone believe the hard evidence? I suppose the difference between me and a vinyl advocate might lie with the fact that I have not invested $10k in a super turntable/class A tube amp/"oxygen-free" speaker cabling as-thick-as-my-thumb system. Those that have done so might really need to cling to any theory they can find that might justify their investments, and the less scientific the theory, the better. Harder to debunk subjective criteria when such criteria can be rhetorically shoe-horned around any attempts to quantify them and design experiments to verify claims.

If ABX testing conclusively debunks this stuff, why are people still arguing it?

An ironic aside/confession--I recently bought a tape sim for my recording projects, which adds even series harmonic distortion, squashes dynamics a bit, and rolls off high end in the way an analog master tape might--so I guess that I, too, sometimes show an affinity for a more antiquated "analog" sound (albeit one faked via software). If the sonic signature of vintage equipment is what sounds great to a listener, that's fine, so long as one admits that the familiarity of such sounds is why a person is fond of vinyl. No need to invent theories to justify one's preference for that particular sound, is there?

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WernerO
post Jan 5 2012, 08:56
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Perhaps time for a bit of history?

The whole PRaT thing emerged in the UK's flat earth period.

The (subjective) audio press evaluated components and systems mainly
on things like tune playing capability and whether or not you could tap
your foot to it. (Really. Bear with me.)

Back then systems that, according to said press, 'timed well' typically
centered around one particular turntable, and loudspeakers invariably
optimised for wall mounting and with a particular tonal balance. And these
were, presumably, auditioned in typical UK homes.

Almost invariably any turntable, tonearm, or loudspeaker originating outside
of the UK, and in particular the USA, was deemed hopelessly PRaTless.


So did the favoured components (Linn LP12 TT in its earlier cruder forms, Linn and
Naim loudspeakers) when used in UK rooms, exhibit objective properties that set
it apart from competing products (possibly optimised to other room types), leading
to an enhanced impression of rhythmic flow? IOW did they really hear something?

Or was it all a large conspiracy initiated by Linn dealerships?


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