High Damping Factor and Bass Output

[WmAx]

As for audibility, I've also seen squat with respect to how we compensate for subtle alterations of imaging parameters, especially with respect to the settling time for our perceptions, so again, we use a slowly responding instrument to measure a rapidly changing signal.. More listening tests..insanity, by definition.

Which specific listening test(s) are you referring to?

So, even if somebody thought they heard something different, regardless of the inadequacy of the listening regimen, there is nothing out there to actually correlate the audibility to with respect to actual ele measure..unless one considered the color of the amp faceplate perhaps?

There in lies the catch. No one has yet proved audiblity of a factor in real-world use that is not measured in standardized testing of signal parameters. First step is to reliably observe a difference, otherwise there is nothing to look for, and nothing that can be claimed to make a difference with a degree validity. If reliable observation of a difference that escapes tranditional measurements exists, then you have something for which to search.

-Chris

 

[jneutron]

As for audibility, I've also seen squat with respect to how we compensate for subtle alterations of imaging parameters, especially with respect to the settling time for our perceptions, so again, we use a slowly responding instrument to measure a rapidly changing signal.. More listening tests..insanity, by definition.

Which specific listening test(s) are you referring to?

We image an object via the time and level difference between what gets to both ears. How does a reactively loaded 50 hz signal on one channel affect the midrange imaging parameters? Are all midrange parameter shifts perceived identically, or does an across the spectra shift of .1dB or 10 uSec create an image spread?

Think about how your brain adapts to modifications to the eye stimulus. For example, the 3-d pics where you change the depth/focus correlation to fool the mind, or viewing through a stereo microscope, with one eyepiece vertically shifted with respect to the other...your brain adapts slowly.

Once it is realized that the brain slowly alters the perceptional algorithms, one can include that fact into listening tests.."once you realize the dvm requires a 5 second settling time to .1%, you either wait longer for the accuracy, or accept the inaccuracy inherent in 2 second measurement time."

Why is hearing any different? To believe our hearing localization perception is a fixed transfer function system is foolhardy..That is an assumption that is based on NOTHING, but is simply an erroneous assumption.

There in lies the catch. No one has yet proved audiblity of a factor in real-world use that is not measured in standardized testing of signal parameters. First step is to reliably observe a difference, otherwise there is nothing to look for, and nothing that can be claimed to make a difference with a degree validity. If reliable observation of a difference that escapes tranditional measurements exists, then you have something for which to search.
-Chris

Alas, everybody is running around "holdin the dvm for half a second", then arguing about the results. Or, worse yet, using the "AC" setting while looking for "DC"..

Rapidly switching dbt's for localization is trivially useless...an exercise in insanity. To use such to "prove" a difference is meaningless.

One must understand the measurement system and it's shortcomings first. I have pointed out those faults within our hearing, as well as within our measurements. There is no catch...localization characteristics are not understood, nor is the measurement of dynamic four quadrant damping factor. Learning curve..

Cheers, John

 

[WmAx]

We image an object via the time and level difference between what gets to both ears. How does a reactively loaded 50 hz signal on one channel affect the midrange imaging parameters? Are all midrange parameter shifts perceived identically, or does an across the spectra shift of .1dB or 10 uSec create an image spread?

Induce such changes purposely in a test system and conduct properly controlled listening tests to find out.

Once it is realized that the brain slowly alters the perceptional algorithms, one can include that fact into listening tests.."once you realize the dvm requires a 5 second settling time to .1%, you either wait longer for the accuracy, or accept the inaccuracy inherent in 2 second measurement time."

The majority of listening tests, such as most ABX situations, use a user controlled switching system where they can listen for as long or short a time as they wish; whatever is needed to make a distinction. It comes down to, if you can't make a distinction in actual listening, what is supposed to be audible?

Why is hearing any different? To believe our hearing localization perception is a fixed transfer function system is foolhardy..That is an assumption that is based on NOTHING, but is simply an erroneous assumption.

Who made such a statement?

Rapidly switching dbt's for localization is trivially useless...an exercise in insanity. To use such to "prove" a difference is meaningless.

Please present a better test methodology. Anything that does not have a short time span between changing from one signal to the next is going to decrease sensitivity to changes, because human auditory memory is very short.

-Chris

 

[jneutron]

Originally Posted by jneutron
We image an object via the time and level difference between what gets to both ears. How does a reactively loaded 50 hz signal on one channel affect the midrange imaging parameters? Are all midrange parameter shifts perceived identically, or does an across the spectra shift of .1dB or 10 uSec create an image spread?

Induce such changes purposely in a test system and conduct properly controlled listening tests to find out.

Yup, this is what I am saying. Determine our sensitivity to ITD and IID vs frequency for differential localization. The test must be able to measure the shifting of two different frequencies in an image w/r to each other, given a third stimulus that alters both ITD and IID differentially.

Once it is realized that the brain slowly alters the perceptional algorithms, one can include that fact into listening tests.."once you realize the dvm requires a 5 second settling time to .1%, you either wait longer for the accuracy, or accept the inaccuracy inherent in 2 second measurement time."

The majority of listening tests, such as most ABX situations, use a user controlled switching system where they can listen for as long or short a time as they wish; whatever is needed to make a distinction. It comes down to, if you can't make a distinction in actual listening, what is supposed to be audible?

We have no direct measurement of the timeframe required to re-adjust to a new set of ITD/IID cues vs the intensity of those shifts, either independently, or in a confounding situation. The simple assumption is that if the image differential shift is close to the boundaries of our discrimination, the longer it will take to discern. Lacking hard measurments, it is not possible to guess as to the mathematical relationship.

Why is hearing any different? To believe our hearing localization perception is a fixed transfer function system is foolhardy..That is an assumption that is based on NOTHING, but is simply an erroneous assumption.

Who made such a statement?

It is implicit in all the dbt arguments. See your next statement, that is consistent with historical arguments..you are relying on MEMORY to discriminate changes. What a silly method. You (well, not you per se, but everybody) believe that the faster you do the changes, the easier the discrimination capability...that is entirely incorrect when the perception system, our hearing and interpretation of localization clues, is dynamically adjusting to the stimulus relationships as we listen.

Please present a better test methodology. Anything that does not have a short time span between changing from one signal to the next is going to decrease sensitivity to changes, because human auditory memory is very short.
-Chris

That is why any test for this must not rely on the memory. What is required is a direct measure of the localization changes that are perceived based on a change in stimulus.

Given the level of changes we are sensitive to, 5 uSec and roughly .1 dB (ear to ear, not absolute level), NOBODY in the audio industry even knows how to draw current through a speaker cable at that rate, or correctly measure currents that slew that fast into a low impedance.

Larnin curve..

Cheers, John

 

[kingdaddy]

My experiments with crossovers lead me to believe that dampening is most definitely effected by the load, regardless of the output impedance.

A true test to hear dampening at work:

Take a speaker and remove the crossover and replace with an active network and here what audible difference the increase dampening will reveal. I’ve don’t it and was floored at the clean controlled sound that was originally coupled through a simple 5 component passive network, those little caps, inductors and resistors really do a number on dampening from what I can hear. You can even see the cone movement has changed on quite passages (between songs), the passive version would have the mid/woofer flopping around and the active version would be dead still with only a tiny bit of (op-amp) grunge leaking through the tweeters.

 

[jneutron]

My experiments with crossovers lead me to believe that dampening is most definitely effected by the load, regardless of the output impedance.

A true test to hear dampening at work:

Take a speaker and remove the crossover and replace with an active network and here what audible difference the increase dampening will reveal. I’ve don’t it and was floored at the clean controlled sound that was originally coupled through a simple 5 component passive network, those little caps, inductors and resistors really do a number on dampening from what I can hear. You can even see the cone movement has changed on quite passages (between songs), the passive version would have the mid/woofer flopping around and the active version would be dead still with only a tiny bit of (op-amp) grunge leaking through the tweeters.

Damping is the ratio of the load impedance over the drive impedance. The inductor in your crossover altered the damping factor the woofer sees.

From you example, I assume the following:

1. You were using vinyl. The woofer movement between passages was a result of your turntable, and the fact that you did not have a low pass filter in the chain to remove that very very low almost DC component that is caused by the turntable. By substituting an active crossover network before the amp, you probably introduced a rumble filter via capacitive coupling in the signal chain.

2. You greatly increased the damping factor by removing the series inductance of the crossover to the woofer.

3. You provided more headroom by bi-amplification.

4. You probably altered the entire frequency and phase response of your system.

So, it is not possible to really ascribe what you heard as different to one simple variable such as damping factor, there are too many confounding variables you did not control for. It's possible, but you introduced far too many other changes to really say.

Cheers, John

 

[WmAx]

It is implicit in all the dbt arguments. See your next statement, that is consistent with historical arguments..you are relying on MEMORY to discriminate changes. What a silly method. You (well, not you per se, but everybody) believe that the faster you do the changes, the easier the discrimination capability...that is entirely incorrect when the perception system, our hearing and interpretation of localization clues, is dynamically adjusting to the stimulus relationships as we listen.

And if the difference is so small as be compensated for by perceptual system(s), thus rending it undetectable consciously, one should question the value of the difference.

That is why any test for this must not rely on the memory. What is required is a direct measure of the localization changes that are perceived based on a change in stimulus.

I agree, given the context in my previous statement. At this point, it appears you desire brain scanning comparisions with different stimuli applied. Similar to the Oohashi 'Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect' paper, which showed a possibility of brain activity differences for ultrasonic content. But as in that, this would not demonstrate relevance to actual conscious audibility difference(s).

-Chris

 

[WmAx]

A true test to hear dampening at work:

Kingdaddy, I was going to reply with specific information, but jnuetron did it for me.

If you copy the transfer function of the passive crossover(using a DSP crossover that can accomplish this, for example), it will sound identical.

-Chris

 

[jneutron]

And if the difference is so small as be compensated for by perceptual system(s), thus rending it undetectable consciously, one should question the value of the difference.

You do not understand what I meant, I'll try to explain a little better, sorry..

If you are presented with two different 3-d pictures of the same object, but one is designed to make the depth of image 6 inches, the second, 10 inches...and you simply look at them without adjusting your eyes, you will not see depth, and you will not see the difference in depth, you will only see two flat pieces of paper with some ungodly pattern in it.

Your hearing adjusts slowly to the information presented by the system, and the image you perceive eventually settles down to something you like, or dislike.

If you change some if the imaging information a little, either IID or ITD, your brain does not instantly adjust to the change..it takes time. If you rapidly switch in an attempt to retain hearing memory, the result will be null.

As I said, the "meter" in this case, has a settling time..to switch faster than that settling time is to use the meter incorrectly. The difference is not being "compensated" by the perceptual system, it is being hidden by the slow re-configuration time of the perceptual system.

I agree, given the context in my previous statement. At this point, it appears you desire brain scanning comparisions with different stimuli applied. Similar to the Oohashi 'Inaudible High-Frequency Sounds Affect Brain Activity: Hypersonic Effect' paper, which showed a possibility of brain activity differences for ultrasonic content. But as in that, this would not demonstrate relevance to actual conscious audibility difference(s).
-Chris

No, the OOhashi brain scan conclusions were horribly inaccurate. I wish I had been a referee for that paper. It would never have made it to print with such inaccurate, false, silly errors. They would have either re-written it, or buried it.

Humans are indeed sensitive to ultrasonic sound. I, at half a century, am very sensitive to 25Khz sonic energy.

I cannot HEAR that sound, but I am sensitive..big difference.

In the main production bay here, we have a large helium liquification plant, several high temperature vacuum curing/baking ovens, three cranes.. many other loud machines, providing a constant background noise level.

When a hand held ultrasonic welder (for plastics) is activated and I am looking the other way, I can detect it's operation by the reduction in the ambient noise level. The energy of the ultrasonic sound is causing my hearing to gain range downward, exactly like an AGC circuit. This is of course, how the human hearing works, it was surprising to find that even sounds we cannot hear invoke that response.

Cheers, John

 

[WmAx]

You do not understand what I meant, I'll try to explain a little better, sorry..

If you are presented with two different 3-d pictures of the same object, but one is designed to make the depth of image 6 inches, the second, 10 inches...and you simply look at them without adjusting your eyes, you will not see depth, and you will not see the difference in depth, you will only see two flat pieces of paper with some ungodly pattern in it.

Understood.

If you change some if the imaging information a little, either IID or ITD, your brain does not instantly adjust to the change..it takes time. If you rapidly switch in an attempt to retain hearing memory, the result will be null.

As I said, the "meter" in this case, has a settling time..to switch faster than that settling time is to use the meter incorrectly. The difference is not being "compensated" by the perceptual system, it is being hidden by the slow re-configuration time of the perceptual system.

Can you propose a specific methodology that will allow for a control study to determine actual audiblity of the factors that you suspect may be audible?

No, the OOhashi brain scan conclusions were horribly inaccurate. I wish I had been a referee for that paper. It would never have made it to print with such inaccurate, false, silly errors. They would have either re-written it, or buried it.

I agree it's not a very well concluded paper; but I did not mean to imply that I agree with his conclusions. I was referring to the method which he used to show ultrasonic detection(which btw, his results make no sense to me since he could not show any difference activity with only ultrasonic presence, and his listening test was ambiguously detailed, and his listening test conclusion claims were not supported by NHK labs when they performed a more careful analysis/experiment on multiple subjects in response to Oohashi).

When a hand held ultrasonic welder (for plastics) is activated and I am looking the other way, I can detect it's operation by the reduction in the ambient noise level. The energy of the ultrasonic sound is causing my hearing to gain range downward, exactly like an AGC circuit. This is of course, how the human hearing works, it was surprising to find that even sounds we cannot hear invoke that response.

Cheers, John

I have heard of this effect before; but I have not had an opportunity to expereience such high ultrasonic SPL.

-Chris

 

[jneutron]

Can you propose a specific methodology that will allow for a control study to determine actual audiblity of the factors that you suspect may be audible?

Yes, I can.

I agree it's not a very well concluded paper; but I did not mean to imply that I agree with his conclusions. I was referring to the method which he used to show ultrasonic detection(which btw, his results make no sense to me since he could not show any difference activity with only ultrasonic presence, and his listening test was ambiguously detailed, and his listening test conclusion claims were not supported by NHK labs when they performed a more careful analysis/experiment on multiple subjects in response to Oohashi).

I have heard of this effect before; but I have not had an opportunity to expereience such high ultrasonic SPL.
-Chris

I'm not sure how high it was. But the fact of it scared me enough to call the safety guys.

At the time I balked, the osha specs didn't cover the freq range..the guy came in with a ratshack meter, and claimed it was ok..

Yah, right..we don't know if the meter is sensitive to the frequency...

Cheers, John

 

[WmAx]

Yes, I can.

Would you please outline the proposed methodology?

I'm not sure how high it was. But the fact of it scared me enough to call the safety guys.

At the time I balked, the osha specs didn't cover the freq range..the guy came in with a ratshack meter, and claimed it was ok..

Yah, right..we don't know if the meter is sensitive to the frequency...

Cheers, John

The RS meter's accuracy is nill >8000Hz. I am not sure if the RS meter has a useful response of any type at even 20kHz, much less ultrasonic frequencies. That is an inappropriate product to measure ultrasonic SPL. I'm not sure if any commercially available SPL meters are rated for ultrasonic. This will require a special high bandwidth measurement microphone, a regular spl meter(to measure SPL at a known lower frequency to have a SPL reference point with the measurement microphone amplitude) and a computer with a high sampling rate ADC, or an oscilloscope to properly analyse.

-Chris

 

[jneutron]

Would you please outline the proposed methodology

No.....but I can...heh heh..

Seriously, my ride is here now, I gotta shut down..another day I'll detail..

The RS meter's accuracy is nill >8000Hz. I am not sure if the RS meter has a useful response of any type at even 20kHz, much less ultrasonic frequencies. That is an inappropriate product to measure ultrasonic SPL. I'm not sure if any commercially available SPL meters are rated for ultrasonic. This will require a special high bandwidth measurement microphone, a regular spl meter(to measure SPL at a known lower frequency to have a SPL reference point with the measurement microphone amplitude) and a computer with a high sampling rate ADC, or an oscilloscope to properly analyse.

-Chris

T'was why I didn't care for the answer given by the safety guys here.

Till T'morrow..

Cheers, John

 

[kingdaddy]

Kingdaddy, I was going to reply with specific information, but jnuetron did it for me.

If you copy the transfer function of the passive crossover(using a DSP crossover that can accomplish this, for example), it will sound identical.

-Chris

Don’t see how this could be true, a passive devise between the drivers VC and the amps output stage will no doubt cause some negative effects, phase just being one of them. Removing this and having the amp directly control the drivers VC will in my experience increase control and leave phase unaltered.

 

[WmAx]

Don’t see how this could be true, a passive devise between the drivers VC and the amps output stage will no doubt cause some negative effects, phase just being one of them.

First, it is unclear which phase (electrical or signal) to which you are referring. Signal phase will be the same regardless if the change is done at line level(active crossover) or speaker drive level(passive crossover). Thus you can copy the transfer functions of any passive crossover with a DSP version and it behave identically, audibly. If you mean electrical phase, as is presented to the amplifier, this will be different for a passive crossover, but most solid state amplifiers will have no problems with the phase angle loads presented by typical speaker systems regardless, because most amplifiers are designed to operate with stability at +/- 45 degrees electrical phase.

Removing this and having the amp directly control the drivers VC will in my experience increase control and leave phase unaltered.

Claims of sound difference in this matter up to this point are speculative. There is not mystery 'X' factor that is demonstrated to exist. These are all basic electrical and acoustical interactions that are quantifiable. All that increasing source/series resistance does is to increase the difference of delivered voltage to the load in dynamic impedance contrasts, which results in a frequency response modification. Again, easily copied with a DSP system.

An active crossover system should sound different than a passive in many applications. But this has nothing to do with dampening factor, etc.. It is easier to work with an active crossover, and it provides more correction possibilities than a passive due to cost and complexity contraints of implimenting some things into passive high signal level applications. Because matching driver sensitivity is no longer an issue when using active systems, you also have a much wider selection of drivers to mix and match.

I suspect that the experiences that you speak of have zero controls in place to perform a proper listening test.

-Chris

 

[mtrycrafts]

No, the OOhashi brain scan conclusions were horribly inaccurate. I wish I had been a referee for that paper. It would never have made it to print with such inaccurate, false, silly errors. They would have either re-written it, or buried it..

Cheers, John

Did you read the footnotes at the bottom of the paper?

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

This is not a peer reviewed paper but an advertisement, bought and paid for.

 

[mtrycrafts]

No.....but I can...heh heh..

Cheers, John

Nothing will be solved here other than exchanging info. What needs to be done is talking with the heavy hitters, CRC in Canada, perhaps Toole at Harman, AES and ASA to get them interested. You can explain it here until you are blue in the face. That will not get this tested and researched or published.

 

[jneutron]

Did you read the footnotes at the bottom of the paper?

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

This is not a peer reviewed paper but an advertisement, bought and paid for.

No, I did not read the footnotes. I read a bit, but very quickly understood the errors in the paper, so stopped. Once the initial assumptions are shown to be incorrect, the rest of the paper which builds on it are useless.

It is certainly possible that it is simply an advertisement, but that footnote does not eliminate the possibility that it was indeed peer reviewed. It only shows by law, how the cost of publication was borne.

Cheers, John

 

[jneutron]

Nothing will be solved here other than exchanging info.

There is nothing wrong with exchanging information. Isn't that the point of this forum?

What needs to be done is talking with the heavy hitters, CRC in Canada, perhaps Toole at Harman, AES and ASA to get them interested.

From the publications I have seen of the "heavy hitters", I have at times been underwhelmed. While a lot of their knowledge is rather good, there are clearly areas which they are not very well versed. From what I have read to date, this fact has not stopped them from making erroneous assumptions and thereby, inaccurate conclusions.

They do not understand e/m theory as it applies to low impedance, high current slew rate circuitry..they do not understand differential localization. They do not understand the time based human localization shifts in perception. They do not correctly apply Maxwell's equations..

I do not have the time to teach them what they need to know..That will only be accomplished in the long term, I will not hand them all on a platter, knowledge needs to be learned. I am lucky in that I work with people who are very very far above me in knowledge, so I can learn. And, they do not hand me the answer on a platter either.

You can explain it here until you are blue in the face.

I do not turn blue in the face..I breath while I type.

That will not get this tested and researched or published.

That is an issue if one desires to publish..

Cheers, John

 

[mtrycrafts]

It is certainly possible that it is simply an advertisement, but that footnote does not eliminate the possibility that it was indeed peer reviewed. It only shows by law, how the cost of publication was borne.

Cheers, John

Yes, it is possible that it was reviewed but authors usually don't pay to have their papers reviewed and published, do they?