[bhobba]

That's very interesting, Bill, as I have been having an "argument" with someone about how on earth one could measure the "Factor X" in a SET amp (actually, Hugh's "Glass Harmony") which causes it to present a singer as being 5' in front of the image produced (in the same speakers) by a Lifeforce 100 amp.  I would've thought this has nothing to do with a different pattern of harmonic distortions (ie. between 'glass' and 'sand') ... but what could it be?     It makes sense that maybe one could use DSP to push the image of a Lifeforce 100 forward in space but what amplifier parameters would one be adjusting with the signal processor?

Previously when I was posting regularly I had a number of discusions about the objectivity vs subjectivist arguments.  My take is you should be able to double blind the differences.  Objectiveists argue they are on firm ground judged on that basis.  I am not so sure.  As I mentioned then blind test after blind test showed it was not possible to tell the difference between the original and high bit rate MP3.  One guy, who had developed other coding mechanisms, got really annoyed about this.  He took the double blind challenge and blew it out of the water - he could easily pick it blind.  His explanation.  Once you have studied the technicalities and know what to look for, what others can't pick, becomes all too obvious.  He claimed he could easily train people to pick it.  My take is that what the subjectivists talk about is real, and comes from critical listening that the average person simply isn't interested in.  It is not golden ears - it is simple practice.  I believe something similar is happening with valves.  Those that listen critically to Hi Fi don't have golden ears - they are simply more attuned to the subtleties.

Thanks
Bill

[Kevin Haskins]

I think what changes is the distortion spectrum and it can change our perceived spacial perception.   I hear the same thing from my 300Bs, you get a perceived wider soundstage.   

Our brain is a complex device and how it interprets and processes information is an interesting science.   Usually it processes spatial information in terms of delay and direction but there must be some correlation with even order types of distortion that allows our brains to fill-in or deceive us into hearing a larger space. 

I don't honestly know enough about the research to do anything but give you an educated guess though. 

[kyrill]

take real life perfomances as yr reference.

how can extra distortion in valve amps give this elusive "life" perception as those distortions are COMPLETELY absent in the life performance?

I really belief NO ONE on earth knows enough about it how extreme sensitive ear/brain interfaces are and pick up things we never dream about to design an apparatus for  to measure this "thing"

[JohnR]

Perhaps they mask other (worse) distortion already there, or perhaps it's simply a trade-off and those "higher" amounts of low-order distortions are just less objectionable than minute amounts of higher-order distortion. (I've seen an amp put on the bench with a low THD number but visible components all the way up to the 20th). Or perhaps harmonic distortion is irrelevant to what we hear and other forms of distortion are more significant.

(I'm sure someone must have already said this, though... my apologies, I haven't been following the thread.)

[kyrill]

hi John

is not every public forum ( especially Hugh's)  an open invitation for every world inhabitant ( rest of universe not connected yet ) to join?

yr explanation seems valid. so in stead of curing the "mal" we found a way to counter the mal with another mal--> symptom correction

[bhobba]

I think what changes is the distortion spectrum and it can change our perceived spacial perception.   I hear the same thing from my 300Bs, you get a perceived wider soundstage.   

Our brain is a complex device and how it interprets and processes information is an interesting science.   Usually it processes spatial information in terms of delay and direction but there must be some correlation with even order types of distortion that allows our brains to fill-in or deceive us into hearing a larger space. 

I don't honestly know enough about the research to do anything but give you an educated guess though. 

Nor do I really.  But I do have 'faith' in blind listening tests.  I suspect more 'proper' research needs to be done in this area.  I am rather impressed with Jon Risch's views.  Although about cables I think its principles apply generally
http://www.videohifi.com/16_RISCH_ENG.htm
'I reported to my supervisor that I had found at least one cable sample that seemed to sound much better than the others, and was even better than the then currently Japanese sourced Gold-Ens. He was also incredulous, and did not quite believe me. So a formal listening test was scheduled to test between the existing cables, and the new sample I preferred, and I was placed under blind conditions (double-blind equivalent). A variation on the original ABX procedure was used, with hand swapping of the cables, instead of a switch box. Much to the amazement of my supervisor and fellow engineers, on the first set of ten trials, I scored 8 out of 10 (still warming up), then 9 out of 10, then 8 out of 10 again. I could tell I was getting fatigued on the last run, and said so. Taken as a whole, the three trials together, for 25 out of 30, approaches near certainty. This was the beginning of my long journey with audio cables, and the why and wherefore. Since 1980, I have been conducting controlled listening tests on audio components, most of which were for audio cables. After literally hundreds of cable listening tests under controlled conditions, I have no doubt personally that cables can be detected and some sound better than others. I know this, and no one can take this away from me, there were too many tests with overwhelming positives, too much rigorous science involved. After conducting many tests, and finding out early on that they were not always so easy to get results from, I found that there were weak spots in the original ABX procedures, and with many of the amateur DBT's that had been, and were being run (mostly by cable naysayers). I wrote and presented an AES paper in 1991, AES preprint #3178, outlining some of the issues connected with listening tests, and based on my own experiences with having conducted so many listening tests.'

Thanks
Bill

[Steve Eddy]

Previously when I was posting regularly I had a number of discusions about the objectivity vs subjectivist arguments.  My take is you should be able to double blind the differences.  Objectiveists argue they are on firm ground judged on that basis.  I am not so sure.  As I mentioned then blind test after blind test showed it was not possible to tell the difference between the original and high bit rate MP3.

I know the guy who developed MP3 and I don't believe even he has ever made such a claim.

One guy, who had developed other coding mechanisms, got really annoyed about this.  He took the double blind challenge and blew it out of the water - he could easily pick it blind.  His explanation.  Once you have studied the technicalities and know what to look for, what others can't pick, becomes all too obvious.  He claimed he could easily train people to pick it.

And as the person I mention above has said numerous times, listener training is a critical part of double blind testing.

My take is that what the subjectivists talk about is real, and comes from critical listening that the average person simply isn't interested in.  It is not golden ears - it is simple practice.  I believe something similar is happening with valves.  Those that listen critically to Hi Fi don't have golden ears - they are simply more attuned to the subtleties.

It's certainly possible. But then one would expect that one of them would have been able to demonstrate such abilities by now.

se

[Steve Eddy]

So a formal listening test was scheduled to test between the existing cables, and the new sample I preferred, and I was placed under blind conditions (double-blind equivalent). A variation on the original ABX procedure was used, with hand swapping of the cables, instead of a switch box.

Double-blind equivalent? No. If someone is swapping the cables by hand, then it's a decidedly single-blind test.

se

[bhobba]

I know the guy who developed MP3 and I don't believe even he has ever made such a claim.

Opinions vary.  Typical of those that claim it can not be distinguished is the following:
http://www.geocities.com/altbinariessoundsmusicclassical/mp3test.html

The guy that helped develop the alternative coding scheme (I think it was MPC which is continuously being refined) was able to reliably do it.  If I recall correctly he was able to even pic MPC, which by reputation is very transparent - but is was a lot harder.

Thanks
Bill