I agree with Anatoliy; many things heard by audiophiles, particularly those oft-reported comments about sound stage depth and musicality, are fact. But they are not measureable, at least not commonly.
Green bands around the CD, pet rocks on the amp cabinet, magic crystals near the vinyl pickup and porcelain stand-offs on the speaker cable are obviously very dubious, and to lump them in with all audiophile comments is unjust. Very few are that extreme....
Hugh
Green bands around the CD, pet rocks on the amp cabinet, magic crystals near the vinyl pickup and porcelain stand-offs on the speaker cable are obviously very dubious, and to lump them in with all audiophile comments is unjust. Very few are that extreme....
Hugh
..and some just question you on PIM when you're orders of magnitude off..
the only way I know to get "10 microsecond PIM" is from a single full range driver Doppler distortion - which is PIM
not from (high negative feedback) amplifiers
the only way I know to get "10 microsecond PIM" is from a single full range driver Doppler distortion - which is PIM
not from (high negative feedback) amplifiers
That means, even much less deviation matters than absolute phase shift needed to recognize phantom image shift. 10 microseconds was a number obtained experimentally, and it was stunning find, because nobody believed then that phase shifts equal to 100 KHz wavelength can be audible.
Now it is already accepted as a real fact by the same people who argued against... 😉
the justaposition of the two paragraphs in your post implied you believe Amplifier PIM is an Audible issue - what are you saying here?
interaural time delay resolution is easily explained by neural processing cross correlation -exended observation time, dynamic range can give high resolution without requiring 100 KHz bandwidth
as a inter-channel property is is expected that matching phase errors/group delay in R,L channels don't have much effect
none of which gives any reason to expect 3-5 orders of magnitude smaller Amplifier PIM is audible
interaural time delay resolution is easily explained by neural processing cross correlation -exended observation time, dynamic range can give high resolution without requiring 100 KHz bandwidth
as a inter-channel property is is expected that matching phase errors/group delay in R,L channels don't have much effect
none of which gives any reason to expect 3-5 orders of magnitude smaller Amplifier PIM is audible
When something real does not correspond to theoretical expectations I prefer to think that the theory used is not applicable to this particular case. Or at least incomplete. Neural processing explains nothing. It gives a confidence to people who want to believe in science, no more. It is their religion, and I don't argue about religious beliefs.
Hello
I did read some of Renardson articles a years ago but his article about phase Intermodulation show that one alternative solution are to use the JLH phase lead capacitor or a variation of it.
I did know that using a phase lead capacitor can reduce the size of the cdom capacitor in the vas giving a better slew rate, now it seem that a phase lead capacitor can reduce the phase Intermodulation, so it's another reasons why an amp using a phase lead capacitor will sound with a better sound stage.
Bye
Gaetan
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I'm really missing the logic here - granting microsecond inter-aural group delay resolution from psychoacoustic testing is "real" - I do belive the headphone testing showing single digit microsecond JND resolution - the moving speaker driver experiment is laughably ill concieved on frequency response flatness grounds alone
it still has nothing to say about PIM audibility of amplifiers with nanosecond measured PIM
it still has nothing to say about PIM audibility of amplifiers with nanosecond measured PIM
This is why full range speakers with small diaphragm and long throw excursion will never sound real.
But Doppler effect of speakers and PIM of amplifiers add different kinds of a dirt: the first one is organic, mechanical, it surrounds us during all evolution of human species, we don't hear reflected from surfaces sounds as distorted, while sounds altered by electronics we hear as distorted, in-natural.
But Doppler effect of speakers and PIM of amplifiers add different kinds of a dirt: the first one is organic, mechanical, it surrounds us during all evolution of human species, we don't hear reflected from surfaces sounds as distorted, while sounds altered by electronics we hear as distorted, in-natural.
JCX,
You argue in the combative academic style. I believe this is confronting.
Why not pick an engineering forum for this style, rather than a DIY forum? It seems you wish to enjoin Anatoliy in a full on, academic debate - this is hardly the place for that, why not do it by email or PM?
How about having a stab at image depth? It's difficult, if not impossible, to measure. It is a very real, albeit subjective characteristic, perhaps it can be explained in electrical terms?
Hugh
You argue in the combative academic style. I believe this is confronting.
Why not pick an engineering forum for this style, rather than a DIY forum? It seems you wish to enjoin Anatoliy in a full on, academic debate - this is hardly the place for that, why not do it by email or PM?
How about having a stab at image depth? It's difficult, if not impossible, to measure. It is a very real, albeit subjective characteristic, perhaps it can be explained in electrical terms?
Hugh
diyers still make circuit topology, biasing, parts choices - why would discussing engineering principles in context with psychoacoustic results be unwelcome?
We can discuss, but in the direction of extrapolation only, because in order to measure threshold of audible deviation we need to have some ideally sounding system with possibility to gradually add PIM deviation. Do we have it? No. But extrapolation helps me to achieve better and better results. However, it can be wrong, like in 1800'th British authorities extrapolated environmental pollution and concluded that the main problem of the 20'th century will be removal of horse poop from streets. 😉
And they were right in the principle itself while being wrong
about its exact expression, since pollution resulting from
transportation means actually became a problem...😉
Does it help? No. Removal of THD revealed that it was not the right indicator. Like, removal of the source of pollution (horses).
We know that "amplification means actually the problem", like transportation. But what should be improved? This is the question. 😉
Few things , if anything.
Audio amplification has reached a point at wich any progress
can only be a very marginal one, and unlikely of being audible.
There s much more to gain by improving the speaker s quality,
wich in comparison to amplifiers, are still on the stone age
in respect of their poor performances that makes them the
only element of the audio chain whose defects are very
clearly and unanimously audible.
But what if it is again a wrong direction, and we use wrong amplifiers to drive them?
My experiments with combination of feedbacks by voltage and current in order to match output impedances of an amp and a speaker were very promising. However, it caused further loss of efficiency...
My experiments with combination of feedbacks by voltage and current in order to match output impedances of an amp and a speaker were very promising. However, it caused further loss of efficiency...
Then why do so many prefer tubes, which we all know have massive THD?
Perhaps we are measuring the wrong thing, as the correlation with the subjective experience appears so tenuous?
May I repeat my question about image depth, JCX?
Hugh
Perhaps we are measuring the wrong thing, as the correlation with the subjective experience appears so tenuous?
May I repeat my question about image depth, JCX?
Hugh
Like, some (often very rich) people prefer horses that we know have only 1 HP, very limited speed, and cause environmental pollution.
The amplifiers would be the wrong ones if ever they would be sub par in
respect of the speaker s fidelity, wich is evidently not the case.
Tweaking the amps to compensate for the speaker s innaccuracies
and high distorsion can be a solution, but so far, the most interessant
one , Phillips s MFB seems to have been more or less abandonned,
surely due to lack of correct and affordable microphonic captors.
That said, personnaly, the current available audio technology
seems to me quite enough for most if not all ears...
Wahab,
Given the colorations which abound in the audio world, particularly with speakers, I can't help thinking the choice of system is a matter of taste for many. Not for engineers, mind, as they want the least possible measured distortion, an ideological fixation you could say, but for many audiophiles.
I'm not looking for argument, just opining on what people want.....
Hugh
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