Speaker Cable Length Differences: Do they matter?

[jneutron]

Email me if you want any of these full articles in pdf form.

You have got to be kidding me...if you don't send all four to me, I will hunt you down.. thanks..I'll PM ya..

Banks, M. S. (2004). "Neuroscience: what you see and hear is what you get." Curr Biol 14(6): R236-8.

The brain receives signals from a variety of sources; for example, visual and auditory signals can both indicate the direction of a stimulus, but with differing precision. A recent study has shed light on the way that the brain combines these signals to achieve the best estimate possible.

They need to learn how to write an abstract if they wanna sell papers..it would be nice to know what the way is they allude to.

Bernstein, L. R. (2001). "Auditory processing of interaural timing information: new insights." J Neurosci Res 66(6): 1035-46.

Differences in the time-of-arrival of sounds at the two ears, or interaural temporal disparities (ITDs), constitute one of the major binaural cues that underlie our ability to localize sounds in space. In addition, ITDs contribute to our ability to detect and to discriminate sounds, such as speech, in noisy environments. For low-frequency signals, ITDs are conveyed primarily by "cycle-by-cycle" disparities present in the fine-structure of the waveform. For high-frequency signals, ITDs are conveyed by disparities within the time-varying amplitude, or envelope, of the waveform. The results of laboratory studies conducted over the past few decades indicate that ITDs within the envelopes of high-frequency are less potent than those within the fine-structure of low-frequency stimuli. This is true for both measures of sensitivity to changes in ITD and for measures of the extent of the perceived lateral displacement of sounds containing ITDs. Colburn and Esquissaud (1976) hypothesized that it is differences in the specific aspects of the waveform that are coded neurally within each monaural (single ear) channel that account for the greater potency of ITDs at low frequencies rather than any differences in the more central binaural mechanisms that serve these different frequency regions. In this review, the results of new studies are reported that employed special high-frequency "transposed" stimuli that were designed to provide the high-frequency channels of the binaural processor with envelope-based information that mimics waveform-based information normally available only in low-frequency channels. The results demonstrate that these high-frequency transposed stimuli (1) yield sensitivity to ITDs that approaches, or is equivalent to, that obtained with "conventional" low-frequency stimuli and (2) yield large extents of laterality that are similar to those measured with conventional low-frequency stimuli. These findings suggest that by providing the high-frequency channels of the binaural processor with information that mimics that normally available only at low frequencies, the potency of ITDs in the two frequency regions can be made to be similar, if not identical. These outcomes provide strong support for Colburn and Esquissaud's (1976) hypothesis. The use of high-frequency transposed stimuli, in both behavioral and physiological investigations offers the promise of new and important insights into the nature of binaural processing.

Now, THAT's an abstract...I'm chompin at the bit.....it'll be interesting to see if their method of transposition is in any way similar to Nordmark's jitter method. Nordmark has 500 hz as the start of lateralization sensitivity, 1.2Khz as the end of unjittered sensitivity, and 12K plus with jitter included.

McAlpine, D. and B. Grothe (2003). "Sound localization and delay lines--do mammals fit the model?" Trends Neurosci 26(7): 347-50.

The current dominant model of binaural sound localization proposes that the lateral position of a sound source is determined by the position of maximal activation within an array of binaural coincidence-detector neurons that are tuned to different interaural time differences (ITDs). The tuning of a neuron for an ITD is determined by the difference in axonal conduction delay from each ear--the so-called "delay line" hypothesis. Although studies in birds appear to support this model, recent evidence from mammals suggests that the model does not provide accurate descriptions of how ITDs are encoded in the mammalian auditory brainstem or of how ITD-sensitive neurons contribute to mammalian sound localization.

They seem to be a bit confused with their conduction delay speak, as delay lines won't help lateralization, unless they are talking about the same thing digital filter guys do. Not a clear abstract...

Schnupp, J. (2001). "Of delays, coincidences and efficient coding for space in the auditory pathway." Trends Neurosci 24(12): 677-8.

To localize a sound source in space, the auditory system detects minute differences in the arrival time of a sound between the two ears. It has long been assumed that delay lines and coincidence detectors turn these time differences into a labelled line code for source position, but recent studies challenge this view.

Better abstract..

After a quick read, I think the Bernstein article might be the most useful.

From the abstracts, I certainly agree.

Their model is gonna hafta include the ability to detect simultaneous frequencies from one source as well..

Thank you very much, Swerd..I look forward to the reading.

Cheers, John

 

[Swerd]

You have got to be kidding me...if you don't send all four to me, I will hunt you down.. thanks..I'll PM ya..

You have mail.

For what its worth, one of those authors is not too far from you, in case you want to talk with someone who apparently thinks a lot about this problem.

Leslie Bernstein
Dept. of Neuroscience
Univ. of Connecticut Health Center
Farmington, CT

When I searched literature under "interaural temporal disparities", she came up with 14 publications since 1985.

Have fun reading

 

[jneutron]

You have mail.

For what its worth, one of those authors is not too far from you, in case you want to talk with someone who apparently thinks a lot about this problem.

Leslie Bernstein
Dept. of Neuroscience
Univ. of Connecticut Health Center
Farmington, CT

When I searched literature under "interaural temporal disparities", she came up with 14 publications since 1985.

Have fun reading

Got them..reading them...thanks.

Interesting, the different buzz words, acronyms. they use lateralization for headphone based imaging, localization for external binaural stimulation...SAM is sine amplitude modulation..

Already spotted some questionable conclusions..At least with Leslie nearby, I'll be able to communicate.

Hmmmm, ITD is a department at work, they are the ones who take away all the "nonconforming hardware".

Cheers, John

 

[Swerd]

Interesting, the different buzz words, acronyms. they use lateralization for headphone based imaging, localization for external binaural stimulation...SAM is sine amplitude modulation..

Here is my take on that jargon.

Lateralization refers to azimuth or horizontal sound localization - can be observed via stereo headphones

Localization - horizontal plus vertical localization - requires open acess to the pinna (the complex folded surfaces of the outer ears), masked by headphones

SAM - may be an acronym made up by the author because of such frequent use in the paper

Neurobiologists have very different common assumptions and language than physicists or EEs

 

[jneutron]

Here is my take on that jargon.

Lateralization refers to azimuth or horizontal sound localization - can be observed via stereo headphones

Localization - horizontal plus vertical localization - requires open acess to the pinna (the complex folded surfaces of the outer ears), masked by headphones

SAM - may be an acronym made up by the author because of such frequent use in the paper

Neurobiologists have very different common assumptions and language than physicists or EEs

Actually, I got the defs from Bernstein..

Page 1036...para 2, halfway down.."Such an intercranial image is said to be lateralized" (dscussion of earphone stimulation with image within the head.)

Same para..."In contrast, sounds emitted by external sources...typically perceived outside the head...referred to as localized..

Same page, right column, 5 lines from bottom..."sinusoidally amplitude modulated (SAM)...."

Different language? Geeze, even I don't understand the physicists...luckily, we have strict rules about dealing with them...Since the magnet factory floor is their natural habitat, they can be seen grazing about...don't feed them, don't excite them, don't stick your arms through the bars of the cages..BTW, there's no such rules pertaining to the engineers like me...we can't harm anyone through the straitjackets..all we can do is drool..

Cheers, John

 

[Richard Black]

"the DPS algorithms embedded within the machines are not sensitive to temporal distortions that trash lateralization imaging."

Of course they are, it's called phase distortion, we've all had the technology to measure it for years. People were doing square-wave tests specifically to show it up in a nice easy-on-the-eye sort of form in the 1950s.

"The damping factor is different for absorbtion and delivery."

Actually it's not usually different by much. I've been in the habit of measuring it both ways on amps I review for years, and differences are mostly due to the different levels of the various kinds of tests I use. And I didn't invent the tests - again, lots of people do them.

"The first task at hand is to learn what lateralization is, the criteria for measuring it...."

Yes, as written up by Blumlein in, oh, about 1938, or was it even a few years before that? I'll agree that image _depth_ is a much greater imponderable but lateralisation is not much of a mystery, nor are the means to achieve it.

 

[jneutron]

"the DPS algorithms embedded within the machines are not sensitive to temporal distortions that trash lateralization imaging."

Of course they are, it's called phase distortion, we've all had the technology to measure it for years. People were doing square-wave tests specifically to show it up in a nice easy-on-the-eye sort of form in the 1950s.

We are all quite familiar with the fidelity concerns of square waves, the 10x freq needs, and you are correct...

However, how many amplifiers have you tested at full power, into a speaker load, with two different, randomly frequency changing square waves, and used a piece of equipment to compare the temporal correlation between the outputs, as we are hard wired to do..

A square wave is consistent with the type of thinking that all we need is 20K bandwidth, no more, no less..what you state has nothing to do with 2 channel correlation of a low impedance waveform pair. The term "lateralization" by it's nature, is a discussion of two channels, not one..Have you any experience with a two channel correlation DSP program?

"The damping factor is different for absorbtion and delivery."

Actually it's not usually different by much. I've been in the habit of measuring it both ways on amps I review for years, and differences are mostly due to the different levels of the various kinds of tests I use. And I didn't invent the tests - again, lots of people do them.

More specifically, what is the complex damping factor in all four quadrants..have you any data?

A little more specifically focussed question: what is the damping factor of an amplifier at 5 Khz, driving 50 watts with a 2mH/5 ohm/.1uf load... while simultaneously driving 300 watts rms at 50 hz into a parallel 5mH/8 ohm resistance above the driver/cabinet's resonance frequency...(load numbers just pulled out of the air for flavor...feel free to provide a more real world 3 way speaker impedance model)

And, how does that varying damping factor affect the temporal positioning of the 5K signal.

And, if the second channel is driving 60 hz bass but the same 5K signal, does the other channel act the same? Does it's temporal position (while driving this wildly reactive load pair, retain time fidelity to the 5 uSec level??? And, do you even have the setup to test accurately at the 5 uSec level at low impedance? That is a question I am working on as we speak, with my ultra low b dot/ultra low inductance load resistor...4 ohms, 50 watts, with less than 30 pH inductance by design... I haven't been able to get that result with the meter yet, currently it is reading 1.2 nH, but there are geometric issues with reading that low with any accuracy.

I ask questions about tests I am confident you have never done. That is the point of this conversation...What I describe is not an off the wall scenario..it's a typical music listening event

"The first task at hand is to learn what lateralization is, the criteria for measuring it...."

Yes, as written up by Blumlein in, oh, about 1938, or was it even a few years before that? I'll agree that image _depth_ is a much greater imponderable but lateralisation is not much of a mystery, nor are the means to achieve it.

I'm reading four articles courtesy of Swerd...from 2001 to 2003...from the best researchers in the field of human hearing...you seem to be just a tad bit more confident than they w/r to understanding lateralization and localization..

Perhaps they are unaware of Blumlein?? I can send you the list of authors if you wish to contact them and explain to them how their life work is all a sham..(what were they thinking??).From the papers I am reading, they still don't have a real model.

(sorry with the cheap shot, my apologies...but you incorrectly assumed I was speaking glibly...I do not.)

Cheers, John

 

[Richard Black]

"you incorrectly assumed I was speaking glibly...I do not"

No, I assume you're making life unnecessarily hard for yourself. Yes, there's more to lateralisation than Blumlein knew, but for the purposes of making amplifiers all we need to do is keep interchannel phase and level differences down to sensible levels and keep a tight lid on nonlinear distortion and we've met all the criteria you're talking about.

"And, if the second channel is driving 60 hz bass but the same 5K signal, does the other channel act the same? Does it's temporal position (while driving this wildly reactive load pair, retain time fidelity to the 5 uSec level??? And, do you even have the setup to test accurately at the 5 uSec level at low impedance? "

Taking your last question first - yes, unequivocally. At high impedance (megohms) I admit I'd find it harder but at low impedance my usual test instrument these days - a domestic CD recorder - is good to a few ns.

As for phase shift due to presence or otherwise of a second sinusoid, as it happens I've just been testing exactly that and on the whole amps will do it no bother. Again, it's really not hard to test. A few, with poor IMD, will suffer a bit but usually less than 5us.

 

[jneutron]

"you incorrectly assumed I was speaking glibly...I do not"

No, I assume you're making life unnecessarily hard for yourself. Yes, there's more to lateralisation than Blumlein knew, but for the purposes of making amplifiers all we need to do is keep interchannel phase and level differences down to sensible levels and keep a tight lid on nonlinear distortion and we've met all the criteria you're talking about.

"And, if the second channel is driving 60 hz bass but the same 5K signal, does the other channel act the same? Does it's temporal position (while driving this wildly reactive load pair, retain time fidelity to the 5 uSec level??? And, do you even have the setup to test accurately at the 5 uSec level at low impedance? "

Taking your last question first - yes, unequivocally. At high impedance (megohms) I admit I'd find it harder but at low impedance my usual test instrument these days - a domestic CD recorder - is good to a few ns.

As for phase shift due to presence or otherwise of a second sinusoid, as it happens I've just been testing exactly that and on the whole amps will do it no bother. Again, it's really not hard to test. A few, with poor IMD, will suffer a bit but usually less than 5us.

Don't worry, I am not making life hard on myself...this is a really interesting topic, and melds well with some of my work experiences.

From your statement, you are just using a CD recorder to measure....Yes, you may be measuring something at 5uSec accuracy, but, what?

From my experience, and from your statement, it looks like you have made the assumption that to measure a high slew rate voltage on a low impedance circuit, all you have to do is connect a pair of leads?? And that just by attaching the CD to the speaker terminals, you are actually looking at the real voltage...or current?

Boy, the inaccuracies in that procedure would wipe me out at work..especially the 300 ampere/50 Hz/450 volt driven superconducting MRI stuff...

Your test methods are not accurate....period..I have provided lots and lots of technical explanations over the years on the various forums explaining why that is so.

The reason I am developing such low reactance/low intercept loads, is to first characterize HOW the simple assumptions you have made are inaccurate.. I'll be measuring and writing up for publication, the premise, the procedure, and the results, showing the errors that occur with standard test loads..

In parallel, I delve into the lataralization/localization science, as that is the end application targeted, and one needs to know at what level of speed or accuracy one needs to establish test methods for, to assure wysiwyg.

You seem into it deep..can you post any pictures of your test load and setup? Or, must you keep it company secret?. I will be posting my stuff, but I do not derive income from it. I can, however, take a look at your stuff if you would like, and offer my opinions..or, you can wait till I post/publish..that may be longer than you like..

As for two sinusoids. with reactive loads...one channel 600 hz plus 5K, other channel 500 hz plus 5 K, high pass the outputs from the load, and null them.

Do the 5 K's stay within 1uSec channel to channel temporally?

Do the 500/600 hz signals remain locked to their sources to within 1 uSec?

1 uSec is not human capability, but an arbitrary factor of ten better setpoint I wish to work with..my point being, your setup, I suspect, is incapable of resolution at that level..

Cheers, John

 

[Richard Black]

"1 uSec is not human capability, but an arbitrary factor of ten better setpoint I wish to work with..my point being, your setup, I suspect, is incapable of resolution at that level.."

Of course it is. The limits are timing jitter (order of ns), amplitude jitter (order of -85dB) and nonlinear distortion (order of -100dB) - the respective importance of each of those depending on what exactly one is trying to measure, how, at what frequency. Absolutely no idea what the requirements of MRI superconducting wotsits would be as I've never worked in that area of electronics, but this is audio we're talking about - few tens of V/us, not much over 1A/us (actually with real music considerably less than 1A/us).

No, I can't post pictures of my setup because I haven't got a digital camera. But of course you can just attach a pair of leads at this sort of frequency. It's not hard to prove - just change the length or termination method or something and watch the measurements stay constant within measurement limits - unless you get something harmless but utterly predictable like phase shift (a few millidegrees of phase shift). I've sweated my nuts off playing devil's advocate, trying to measure differences between audio cables, and all I've managed to measure so far is the performance limits (very impressive, in some cases) of various bits of audio and lab kit. I've even 'discovered' a new distortion, at least new to audio, which I spent five days investigating only to decide it is largely an academic curiosity. But it was interesting to investigate it.

 

[jneutron]

"1 uSec is not human capability, but an arbitrary factor of ten better setpoint I wish to work with..my point being, your setup, I suspect, is incapable of resolution at that level.."

Of course it is. The limits are timing jitter (order of ns), amplitude jitter (order of -85dB) and nonlinear distortion (order of -100dB) - the respective importance of each of those depending on what exactly one is trying to measure, how, at what frequency. Absolutely no idea what the requirements of MRI superconducting wotsits would be as I've never worked in that area of electronics, but this is audio we're talking about - few tens of V/us, not much over 1A/us (actually with real music considerably less than 1A/us).

We are speaking apples and oranges...I am quite sure you are correct in your system's capabilities...I am not arguing that.

What I am saying is that you are not measuring the voltage correctly because of the high slew rate currents..ahhh,, guess I'll hafta explain...

Take a 250 watt 8 ohm non inductive resistor..as a load.

It's physical dimensions....say 6 inches long, 2 inches wide..

the physical inductance minimum this load can present: using terman's equation, about .15 uH. And, this is with zero actual resistor inductance.

Now, your 1 amp/uSec slew rate...the reactive voltage across the load: .15 volts at peak slew. The actual voltage across the load is the amp voltage minus this reactive component. you can't measure it...because the loop you form in connecting to this load, picks up the magnetic field that the loop is generating. The best you can do with this load, is to measure the voltage plus the error component. If you could run the test lead through the middle of the resistor, you will break that loop intercept, and read the EXACT load voltage. Note that this error becomes more and more significant as the impedance of the load goes down...this is because the resistive voltage becomes smaller with resistive drop, while the error component remains the same, and is based only on geometry.

You have exactly two choices when measuring slew rates at these impedances...use a Danfysik style current measuring toroid, which is in itself bandwidth limited, or go with a coaxial resistor where the voltage pickup is through the geometric and magnetic center of the resistor..the latter is exactly what I am making..however, I have experience in both, so can advise on the limitations of each.

No, I can't post pictures of my setup because I haven't got a digital camera.

I can, and will do so here if you request.

But of course you can just attach a pair of leads at this sort of frequency. It's not hard to prove - just change the length or termination method or something and watch the measurements stay constant within measurement limits

Actually, I have done so, from 4 Giga amps per second into 1 ohm, 6000 amp half sine into 250 uOhms (here I had to remove the b dot term down to less than 5 millivolts, as I was measuring the temperature of a 3 inch diameter diode during the current pulse), and even at 22 Khz into a .1 ohm resistive load..

What I am explaining to you is exactly what I found in errors, and the methods and designs I had to do in order to eliminate them. Experience in real setups, I am not speaking academically.

Gotta go for now, a tour to guide..

Cheers, John

Note:followup, Jan 14:

You said:

"but this is audio we're talking about - few tens of V/us, not much over 1A/us"

Hmm...a few tens of volts per uSEc? Is that a correct number? If so, then, into 8 ohms, 20 volts/uSec is, 2.5 A/uSec...5 amps/uSec into 4 ohms..let's re-think the numbers...
A power load with .15Uh inductance....
.15 uH load inductance will be 375 millivolts error into 8 ohms, 750 millivolts into 4 ohms.

And, look at a zip cable...200nH per foot, 10 feet, 2 uH...at 5 v/uSec, 10 volts? TEN? You're looking at a 90 degree lagging cosine with 10 volt amplitude...one that you can't readily measure, due to e/m field errors, and a sine measurement will say "zero distortion"..and, the speaker needs the current as that is what forces the voice coil...not the voltage.

Look at my double coax, 10 nH per foot, 100 nH ten feet...into 4 ohms, it will react with half a volt..meaning the current will slew at the speaker more like the amp intended..

Hence my use of the term "sloppy" earlier on..it is a rather unkind sounding word, and really is meant to express how present test methods need to be upgraded. One cannot address current slew rate capability if one does not know how to measure it properly.

Cheers, John

 

[Richard Black]

"Hmm...a few tens of volts per uSEc? Is that a correct number? If so, then, into 8 ohms, 20 volts/uSec is, 2.5 A/uSec...5 amps/uSec into 4 ohms..let's re-think the numbers...
A power load with .15Uh inductance....
.15 uH load inductance will be 375 millivolts error into 8 ohms, 750 millivolts into 4 ohms."

Yup, can't argue with that. But it's still only phase shift and it only follows the usual equations for LCR. Actually, I'm sorry, I was a bit cack-handed with my figures for real world slew rate. Full amplitude 20kHz sine wave from a 200W amplifier is just over 7V/us, or about 2A/us into 4 ohm. That's 4V error in your cable example, against peak amplitude of 56V, about 1/14, which sounds right to me - -3dB point will be about 300kHz. This is a problem why? It's still zero nonlinear distortion and we're just back to arguing the audibility of a few degrees of phase shift at 20kHz. You can measure that phase shift easily enough with or without any knowledge at all of current slew rate.

 

[jneutron]

Yup, can't argue with that. But it's still only phase shift and it only follows the usual equations for LCR. Actually, I'm sorry, I was a bit cack-handed with my figures for real world slew rate. Full amplitude 20kHz sine wave from a 200W amplifier is just over 7V/us, or about 2A/us into 4 ohm. That's 4V error in your cable example, against peak amplitude of 56V, about 1/14, which sounds right to me - -3dB point will be about 300kHz. This is a problem why? It's still zero nonlinear distortion and we're just back to arguing the audibility of a few degrees of phase shift at 20kHz. You can measure that phase shift easily enough with or without any knowledge at all of current slew rate.

Agreed, it follows LCR...never been a problem with that..

A 4 volt cosine error out of 56 gives about 2.5 uSec time shift. Nordmark results are flatline at 1.5 uSec to 12Khz, I don't have the time to re-do for 12Khz, or any lower freq now, gonna go home..I know I can't hear 20K..

I am not worried about phase shift per se...it's the timing errors in the 1.5 to 5 uSec regime that humans are sensitive to that I am speaking of.

Zwislocki et al has 30 uSec capable at 250 hz...(360 degrees/4000uSec)*30 uSec=2.7 degrees phase shift at threshold, while Nordmark has 10 uSec, which is .9 degrees phase shift as threshold. (I'll do up to 12 Khz numbers on Tuesday, I'm outta time...holiday weekend.

300Khz is entirely unimportant, I'm sure we agree..but the time constraints for image localization is certainly in the realm of those numbers.

Enjoy your weekend Robert...it's a pleasure speaking with you. Till we meet again..

Cheers, John

 

[krabapple]

Agreed, it follows LCR...never been a problem with that..

A 4 volt cosine error out of 56 gives about 2.5 uSec time shift. Nordmark results are flatline at 1.5 uSec to 12Khz, I don't have the time to re-do for 12Khz, or any lower freq now, gonna go home..I know I can't hear 20K..

I am not worried about phase shift per se...it's the timing errors in the 1.5 to 5 uSec regime that humans are sensitive to that I am speaking of.

Zwislocki et al has 30 uSec capable at 250 hz...(360 degrees/4000uSec)*30 uSec=2.7 degrees phase shift at threshold, while Nordmark has 10 uSec, which is .9 degrees phase shift as threshold. (I'll do up to 12 Khz numbers on Tuesday, I'm outta time...holiday weekend.

300Khz is entirely unimportant, I'm sure we agree..but the time constraints for image localization is certainly in the realm of those numbers.

Enjoy your weekend Robert...it's a pleasure speaking with you. Till we meet again..

Cheers, John

Any evidence yet that these timing errors are an audible artifact for cables?

 

[jneutron]

Any evidence yet that these timing errors are an audible artifact for cables?

None that I am aware of, although I still try the published research. So far, most of what the "believers" explain is just, floob...and everything I read from the "science" end has audibility holes in it..

I have accepted the fact that I will have to do the measurements and correlations myself...the research is quite lacking, both in the human audibility aspect, as well as the electrical test one.

Just finished a big honeydo project, this one took two months..I now have a break in which I can start building stuff again. That window will close July 10, 2005, and won't open again until February 2006. My expectation is to have the electronics and loads built before that break, and start the audibility part May/June 2006.

In the meantime, maybe someone else will have something built to play with..

Cheers, John

 

[mtrycrafts]

None that I am aware of, although I still try the published research. So far, most of what the "believers" explain is just, floob...and everything I read from the "science" end has audibility holes in it..

I have accepted the fact that I will have to do the measurements and correlations myself...the research is quite lacking, both in the human audibility aspect, as well as the electrical test one.

Just finished a big honeydo project, this one took two months..I now have a break in which I can start building stuff again. That window will close July 10, 2005, and won't open again until February 2006. My expectation is to have the electronics and loads built before that break, and start the audibility part May/June 2006.

In the meantime, maybe someone else will have something built to play with..

Cheers, John

Who are you involving in your audibility tests? Procedures worked out yet?

 

[jneutron]

Who are you involving in your audibility tests? Procedures worked out yet?

Three people, me, myself, and I...unless you count all the multiple personalities, or the voices inside my head...

Procedures are pretty straightforward, stimulus is still an issue, choices are pure freq's, like a (sinx)/x , or a cowbell type, lots of fundamental, good transient, well damped to provide reasonably fast decay. Long decay is an issue when not in an anechoic environment..

Once actual data runs have been performed, with analysis of the data, I'll review the stuff with a high level researcher in this field..There's one about 30 miles away, nice guy, who I've conferred with..if deemed valid, then a real sample size thingy with controls could be done..

But, for my purposes, I'l have a decent set of numbers for at least one (arguably) human..and can set electrical limits about ten times what I can hear.

Cheers, John

 

[krabapple]

None that I am aware of, although I still try the published research. So far, most of what the "believers" explain is just, floob...and everything I read from the "science" end has audibility holes in it..

I have accepted the fact that I will have to do the measurements and correlations myself...the research is quite lacking, both in the human audibility aspect, as well as the electrical test one.

Try running your ideas and findings about cable time shift by the folks discussing cable at Dan Lavry's pro recording forum -- Lavry , Bob Katz, a few others, have some serious technical knowledge to share -- no floob allowed!

http://recforums.prosoundweb.com/index.php/t/3979/0

 

[gene]

Once actual data runs have been performed, with analysis of the data, I'll review the stuff with a high level researcher in this field

Is this gonna happen in our lifetime?

John the parameter limitations of human hearing with respect to frequency response, phase, directionality, spatialization, etc has already been mapped, written about and published in many scientfic journals. A few sources have already been presented such as Everest, AES papers, Harman Research, NRC, etc. There really is no magic here.

Seems like alot of effort on your part to measure the hair on a gnats a**

 

[jneutron]

Try running your ideas and findings about cable time shift by the folks discussing cable at Dan Lavry's pro recording forum -- Lavry , Bob Katz, a few others, have some serious technical knowledge to share -- no floob allowed!

http://recforums.prosoundweb.com/index.php/t/3979/0

I discontinued association with that forum..I found that they were not at the level required to add to the issue. I had hoped otherwise, spent a good half year there..to no avail..

They do have extremely good knowledge, but it is only useful for incremental advances..or solving known issues..not for charting new waters..

Thanks for the info..

Cheers, John