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Perception of Pace/Rhythm/Timing (PRaT) -- genetic?
hollowman
post Jul 4 2011, 16:24
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A somewhat "controversial" topic in audio gear subjective reviewing is the reproduction of Pace/Rhythm/Timing, sometimes abbreviated PRaT. (Sometimes, PRAT with a cap. 'A' may denote A=acceleration). The topic also includes an interdependent subjective metric, dynamics.

Perhaps the seminal introduction to the phenomenon is the Nov. 1992 article in Stereophile, Pace, Rhythm, & Dynamics by Martin Colloms . I noted that this topic is "controversial" in that it not often reported in gear/equipment reviews -- especially in forum- or message-board-based reviews ... where most folks stick to the common (and, IMO, repetitive) BMTS (bass, mids, treble, soundstage). From there, some may additionally describe, e.g., a headphone's 'dynamic' or 'speed' qualities. But when asked to comment on PRaT, the same reviewer responds with puzzlement, smug ridicule, or ignorance.

Pace/Rhythm/Timing -- or PRaT -- is something I'm particularly sensitive too. It is one of the first attributes that I notice the presence or absence of in audio gear, like headphones, all else held equal. I even notice it in slow music, like adagio or lento movements (the Colloms article above goes into this a bit).

Because of the apparent "underreporting" of the "PRaT" phenomenon as important audiological subjective metrics -- and even some hostility as to its importance or even its existence -- I'm wondering how much its perception is genetic. This may be like genetic sensitivity to perfect pitch:
http://perfectpitch.ucsf.edu/study/
Or, more simply, the PTC genetic bitterness test from high-school biology class?

This post has been edited by hollowman: Jul 4 2011, 16:42
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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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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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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.

This post has been edited by benski: Jul 5 2011, 19:52
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Posts in this topic
- hollowman   Perception of Pace/Rhythm/Timing (PRaT) -- genetic?   Jul 4 2011, 16:24
- - greynol   QUOTE (hollowman @ Jul 4 2011, 08:24) I...   Jul 4 2011, 16:43
|- - hollowman   QUOTE (greynol @ Jul 4 2011, 08:43) QUOTE...   Jul 5 2011, 09:11
- - Arnold B. Krueger   QUOTE (hollowman @ Jul 4 2011, 11:24) A s...   Jul 4 2011, 19:22
- - RobWansbeck   Many years after reading the first, 1978, edition ...   Jul 5 2011, 01:28
- - kraut   I find that the thread opener follows the usual au...   Jul 5 2011, 02:19
- - greynol   I truly hope this doesn't end up like it did w...   Jul 5 2011, 02:44
- - krabapple   QUOTE (hollowman @ Jul 4 2011, 11:24) I n...   Jul 5 2011, 03:20
|- - hollowman   QUOTE (krabapple @ Jul 4 2011, 19:20) [.....   Jul 5 2011, 08:48
|- - krabapple   QUOTE (hollowman @ Jul 5 2011, 03:48) QUO...   Jul 5 2011, 15:25
|- - hollowman   QUOTE (krabapple @ Jul 5 2011, 07:25) Wha...   Jul 8 2011, 13:44
|- - db1989   QUOTE (hollowman @ Jul 8 2011, 13:44) gre...   Jul 8 2011, 13:50
- - AndyH-ha   Perhaps the inclination to believe in such things ...   Jul 5 2011, 07:26
|- - Arnold B. Krueger   QUOTE (AndyH-ha @ Jul 5 2011, 02:26)...   Jul 5 2011, 09:20
|- - hollowman   QUOTE (AndyH-ha @ Jul 4 2011, 23:26)...   Jul 5 2011, 09:37
|- - hollowman   QUOTE (hollowman @ Jul 5 2011, 01:37) (se...   Jul 5 2011, 13:17
|- - dhromed   QUOTE (hollowman @ Jul 5 2011, 14:17) Fig...   Jul 5 2011, 16:22
|- - hlloyge   QUOTE (hollowman @ Jul 5 2011, 14:17) I...   Jul 5 2011, 18:22
- - Woodinville   Pace, rhythm and timing are all sensations that co...   Jul 5 2011, 08:09
|- - hollowman   QUOTE (Woodinville @ Jul 5 2011, 00:09) P...   Jul 5 2011, 08:59
|- - Woodinville   QUOTE (hollowman @ Jul 5 2011, 00:59) Not...   Jul 5 2011, 11:01
|- - hollowman   QUOTE (Woodinville @ Jul 5 2011, 03:01) Q...   Jul 5 2011, 11:54
|- - Soap   QUOTE (hollowman @ Jul 5 2011, 06:54) How...   Jul 5 2011, 12:18
|- - hollowman   QUOTE (Soap @ Jul 5 2011, 04:18) QUOTE (h...   Jul 5 2011, 14:05
|- - Soap   QUOTE (hollowman @ Jul 5 2011, 09:05) QUO...   Jul 5 2011, 14:14
- - DonP   We do get the occasional golden eared prat in here...   Jul 5 2011, 13:17
- - Soap   Mods, can you lock this thread already? OP (hollo...   Jul 5 2011, 13:58
- - kraut   QUOTE Extremely refreshing, Kraut Maybe it is ref...   Jul 5 2011, 15:51
- - drewfx   A simple, non-judgmental question: If a system ca...   Jul 5 2011, 16:42
|- - benski   QUOTE (drewfx @ Jul 5 2011, 11:42) A simp...   Jul 5 2011, 19:21
|- - drewfx   If these effects were audible, would you expect th...   Jul 5 2011, 19:38
||- - benski   QUOTE (drewfx @ Jul 5 2011, 14:38) If the...   Jul 5 2011, 19:51
|- - DonP   QUOTE (benski @ Jul 5 2011, 13:21) [ I...   Jul 5 2011, 21:43
||- - greynol   QUOTE (DonP @ Jul 5 2011, 13:43) fuzzily ...   Jul 5 2011, 22:31
||- - Woodinville   QUOTE (greynol @ Jul 5 2011, 14:31) This ...   Oct 16 2011, 05:02
||- - lbstyling   QUOTE (Woodinville @ Oct 16 2011, 04:02) ...   Jan 4 2012, 22:10
|- - Notat   QUOTE (benski @ Jul 5 2011, 12:21) I...   Jul 6 2011, 16:03
- - Soap   They should show up as measurable distortion, no?   Jul 5 2011, 19:46
|- - benski   QUOTE (Soap @ Jul 5 2011, 14:46) They sho...   Jul 5 2011, 19:53
- - drewfx   So then the devil's advocate argument is: 1. ...   Jul 5 2011, 20:18
- - greynol   QUOTE (hollowman @ Jul 5 2011, 01:11) It ...   Jul 5 2011, 21:16
|- - db1989   Having read a little of the Stereophile article li...   Jan 4 2012, 22:39
|- - disfrontman   QUOTE (db1989 @ Jan 4 2012, 16:39) QUOTE ...   Jan 5 2012, 03:29
- - knutinh   1. Find some discussion-forum with a clear profile...   Jul 6 2011, 07:23
- - Nick.C   Likes ^. (we need a like button for posts...... ...   Jul 6 2011, 08:22
- - WernerO   Perhaps time for a bit of history? The whole PRaT...   Jan 5 2012, 08:56


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