John, I think we cross posted. I was thinking a bit more and editing my post when you responded. Any thoughts about intuitive picture I was trying, perhaps incorrectly, to develop?
Following up on Bears question as to how to measure imaging: picture time!
As I mentioned before, the closer a transducer approaches the characteristics of a point source, the better it is for imaging.
This can be measured. A point source will radiate equally in all directions, so by measuring the directivity pattern, important information can be gathered about how well the transducer approaches a point source, and hence the quality of the imaging. The wider the spread and the more even the directivity pattern is, the better imaging will be.
The polar plot of the M2 that was shown earlier in this thread is the result of Toole's and Olive's work in this field. I have been developing from the same premise, but with an important difference. The narrow pattern produced by wave guide based speakers like the Geddes or M2 is sub-optimal in my view.
The speaker I will put on the market shortly departs from the wave guide based approach to directivity control. The result is a much wider listening window, as is born out by this plot from +110 to -110 degrees with a fine (1.5dB) scale:
Over a 180 degree listening angle, there only is about 3dB fall off, except for the highs. What you see on the high end is the physical limitation that even a small diameter tweeter has. There still is a listening angle of 90 degrees for the highs within 3dB, but at my age, the speakers sound almost the same straight on as sideways.
Later this month they will go to anechoic room for a second time to do fine tuning and make further measurements.
The effect this directivity pattern has on stereo imaging is very remarkable. Those going to the Triode Festival this November may get a taste.
One other effect of this directivity pattern is that room dependency appears to be less, rather than more as some may presume.
My working hypothesis to explain this observation is that the Haas effect needs higher frequencies to function optimally. Traditional directivity control collapses below some frequency, so what you get below that frequency are reflections that not corrected by the Haas effect, and are thus perceived as separate sound sources, muddying things up.
As I mentioned before, the closer a transducer approaches the characteristics of a point source, the better it is for imaging.
This can be measured. A point source will radiate equally in all directions, so by measuring the directivity pattern, important information can be gathered about how well the transducer approaches a point source, and hence the quality of the imaging. The wider the spread and the more even the directivity pattern is, the better imaging will be.
The polar plot of the M2 that was shown earlier in this thread is the result of Toole's and Olive's work in this field. I have been developing from the same premise, but with an important difference. The narrow pattern produced by wave guide based speakers like the Geddes or M2 is sub-optimal in my view.
The speaker I will put on the market shortly departs from the wave guide based approach to directivity control. The result is a much wider listening window, as is born out by this plot from +110 to -110 degrees with a fine (1.5dB) scale:
Over a 180 degree listening angle, there only is about 3dB fall off, except for the highs. What you see on the high end is the physical limitation that even a small diameter tweeter has. There still is a listening angle of 90 degrees for the highs within 3dB, but at my age, the speakers sound almost the same straight on as sideways.
Later this month they will go to anechoic room for a second time to do fine tuning and make further measurements.
The effect this directivity pattern has on stereo imaging is very remarkable. Those going to the Triode Festival this November may get a taste.
One other effect of this directivity pattern is that room dependency appears to be less, rather than more as some may presume.
My working hypothesis to explain this observation is that the Haas effect needs higher frequencies to function optimally. Traditional directivity control collapses below some frequency, so what you get below that frequency are reflections that not corrected by the Haas effect, and are thus perceived as separate sound sources, muddying things up.
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Have you read Sound Reproduction and its material on the Haas effect (now more often called the precedence effect)?
And the two channels must be as similar and as symmetric as possible.
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Thanks for the welcomed comment.... if you go back and reread..... it is only an equiv conceptual electrical model for skin effect (HF only). And allows a simple explanation to marketing and buyers alike with no (zero) interest in field theory explanations of reality (including eddy currents etal).
THx-RNMarsh
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Brad, would be mighty obliged if you could point me to where to find this. My sources are Moore, Blauert and Pickles, amongst others.
There is a much-modified third (really second in terms of content) edition in the works, but the first ed. is ISBN 978-0-240-52009-4, from 2008.
The discussion of Haas/precedence is mainly in Chapter 6, Reflections, Images, and the Precedence Effect, pp. 73-93.
Bookfinder shows used copies for under 28 USD.
You among others offered an _possible_ explanation and although it is a plausible one, does it mean that i _has_ to be the correct explanation?
Of course not, so why should it be an unfair question to ask for the reason?
It is an unfair question in that it shows that all past explanations have been ignored. That's disrespectful and frankly, rather stupid.
Of course you can challenge the vast existing and widely accepted understanding of how perception works. Be my guest, we can only learn.
But that's not what he did, he just ignored what didn't fit his agenda.
Jan
Except I don't actually have any "agenda" unless you consider asking why apparently nothing effects the sound unless it consists of gross frequency response aberrations and R, L & C - which is pretty close to summarizing much of what has been written as of late.
As far as "ignoring" past explanations, I am most ignorant of where and when they were offered. I've not read all 1700+ pages, and in fact did not read it much for about 2 years or so at all.
So, Jan, feel free to expound, cite, or link on any issue that I raised.
I'd rather know what the reasonable explanation(s) might be.
But, as I did say, I've yet to listen to two amplifiers (not being the same design and manufacture) that give a sonic impression of being identical.
Nor any 2 DACs.
I'm perfectly open to being shown this happening, and even reading about what tests show that that does happen.
Sorry that you take issue with all of this...
I do not have to go back and re-read. I acknowledged your desire to reach a specific audience and that it did tend towards the effect.
My only caution is that it is not a model that reflects reality specifically at audio frequencies, so caution must be used that it is not portrayed as an actual model for electrical means.
The example that comes to mind was Hawksford's use of an approximation formula inappropriately for a twisted pair magnetic conductor. Trying to make an overly simplistic model may lead to some other guy writing yet another paper that we'll be correcting 30 years from now..sheesh.
John
I'm quite interested in your speaker approach...
...but having said that, having a better speaker which is a great idea, doesn't explain why or IF changing an amp or a DAC ought to alter the perceived soundfield in a given system. Assuming for the moment that we are not talking about bias/prejudice and other self-induced perceptions. I'm saying that the result is altered.
Never heard of anyone being able to measure that, but if they have, great!
If it's never happened to anyone reading, ok fine.
Happens all the time afaik for most people. EVEN when you WOULD PREFER, and rather not hear any change/difference.
Feel free to PM me with critical information, and not tie up the valuable bandwidth here in the thread...
_-_-
I challenge the perceptional 'facts' that imply that we can't trust our ears. In my reality, it doesn't work that way.
This new 'perception research' seems to be generated to discredit quality audio design. It was started by Lipshitz et al about 40 years ago, followed by Toole and Olive. None of it fits in my reality, so I will just keep going making (hopefully) better and better audio designs, based on topology, engineering measurement and listening feedback. Without listening feedback, usually by others that I have come to trust, I have made serious errors, and subsequently marginal audio products, on occasion. I don't want to repeat that experience.
This new 'perception research' seems to be generated to discredit quality audio design. It was started by Lipshitz et al about 40 years ago, followed by Toole and Olive. None of it fits in my reality, so I will just keep going making (hopefully) better and better audio designs, based on topology, engineering measurement and listening feedback. Without listening feedback, usually by others that I have come to trust, I have made serious errors, and subsequently marginal audio products, on occasion. I don't want to repeat that experience.
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Randy, there a wealth of informain available on perception, psycho-acoustics, behavioral models and such that perfectly answer all your questions.
But I'll be dammed if I AGAIN spend many hours to explain and refer it.
Too often I have done this, for, as we say in Holland, 'the cat's vagina'.
Jan
Lots of thoughts.
I use a 6 around 1 super cable, each wire is 13 mils diameter (.013 inch). The cable will run about 1,200 amps easily. But if we run the di/dt above 1/2 amp per second, the conductor will quench at 6/7th of it's capacity. Below that fraction, I can run any di/dt I want. But above it, slow is the word. The user could just turn on a 1 kilo amp supply and run it full in a quarter second. But that last 1/7th must be slow. All of this is due to skinning, the six outer wires see the exact same neighbors so all act the same, but the center wire is symmetrically surrounded so acts differently from the six. Exactly the same thing a normal wire sees at frequency.
A Litz to solid transition will finish redistribution in about 3 to 5 wire diameters.
For rapid cycling magnets running one to two tesla, the half inch square conductors will be more affected by proximity effect, especially where the magfield concentrates. Big concern with ir losses due to that.
John
Yes. That is true - not to apply to audio as a whole. It is for conceptual discussion of skin effect only. It is "As If" the HF Z at the outer surface had lower inductance.... thus, the path for HF. This model can be easily understood and accepted from the teachings of current flows via the least resistance/Z.
Next question ---- is there a phase change or even transit time ddifference between layers (model) of skin depth?
THx-RNMarsh
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Even if it doesn't work as you think it will you have a story that the reviewers will lap up
-Existing effect that the readers may not have heard of
- Belief that you have found something others have missed
-Product delivered using your finding.
The perfect High End story. You should win awards with that.
There may be something to what you say. However, when you talk about "your reality," you aren't helping to explain your case, instead you are undermining whatever else of value you may have to say. Consider that, presumably, there is only one actual physical reality, which is what most scientists and engineers believe. Other people figure that one physical reality to be "their reality", so to them "your reality" must be a purely imaginary one. And if you claim to live in an imaginary reality, then there is no reason to believe anything else you say. Do you see what I mean here? Maybe there is a different way for you to explain what you mean.
'My reality' is the one that I work with and use every day. Your 'reality' might be different, for all that I know, but you might be wrong in some of your beliefs as well as I might be.
I learned long ago, that double blind tests usually give a 'null result' when more open testing always brings back the differences. I can't use a 'null result' for anything. I can use listener feedback to optimize my designs. I am just as much an engineer-scientist as any of you, and I have proven it over the decades. Where are YOUR technical papers on audio design? Mine, I wrote or worked with others back in the 1970's. That is when I did my primary research, later I gained experience by BUILDING various products, you know: Amps, preamps, electronic xovers, studio boards, analog mastering recorders, etc. It is in the 'making' of a successful audio product that makes MY REALITY less than just my imagination.
By the way, people don't believe much in you as well Markw4, when it comes to differences in D-A converters. Does this mean that you are 'imagining' things as well? '-)
I learned long ago, that double blind tests usually give a 'null result' when more open testing always brings back the differences. I can't use a 'null result' for anything. I can use listener feedback to optimize my designs. I am just as much an engineer-scientist as any of you, and I have proven it over the decades. Where are YOUR technical papers on audio design? Mine, I wrote or worked with others back in the 1970's. That is when I did my primary research, later I gained experience by BUILDING various products, you know: Amps, preamps, electronic xovers, studio boards, analog mastering recorders, etc. It is in the 'making' of a successful audio product that makes MY REALITY less than just my imagination.
By the way, people don't believe much in you as well Markw4, when it comes to differences in D-A converters. Does this mean that you are 'imagining' things as well? '-)
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