Hi,
(1) My original challenge was largely suggested from the POV of education/fighting misinformation - which I assume is part of the function of this site/forum.
(2) My challenge was originally not to create a solid state emulation, but create the same sound signature of a particular amplifier (Bottlehead Crack w/out speedball) with a particular set of headphones (Sennheiser 6XX) using DSP alone
(3) My assumption is that if an amplifier is measurably transparent, then the only effects that can be happening from the point of view of the headphones (assuming that two amplifiers are sufficient to power the headphone, of course) is a matter of distortion of the sound, and that such distortion in a limited set of circumstances should in principle be measurable and emulatable - if not, then either the measurement are insufficient to capture everything that would be audible, or there is some mysterious factor that is not measured or measurable (something I find highly doubtful.)
(4) I fully admit that this is something that is outside of my area of expertise and knowledge, so that my failure to achieve this end would be meaningless and the likelihood of my success would be questionable.
My interest in the Project Polaris is a personal matter (I assume this is what you were alluding to when you suggested that one could just build an identical circuit to the Crack, as the ability to emulate using solid state would not really resolve the original issue underlying my challenge.)
PLEASE NOTE: I understand that it would be difficult, if not impossible, to emulate how just any tube amplifier would interact with just any headphone. As I said before (but comments have repeatedly overlooked this) I suggested a particular amplifier (Bottlehead Crack w/out speedball) with a particular set of headphones (Sennheiser 6XX) chosen because these two items are (a) readily available, (b) the 6XX is both relatively affordable and highly regarded on both sides of the objectivist/subjectivist isle, (c) this pairing is a gateway drug for subjectivists (google recommendations for a headphone amplifier for these headphones, and you will soon hear how this pairing is 'magical') and (d) is something that I have seen requested by a number of different users on different sites/forums.
While I myself have long been convinced that subjectivists who claim that there are 'mysterious' and unknown factors that we cannot measure yet are mistaken, this is something that is difficult to prove, especially when people who just shout down any dissent by yelling 'ABX' are offering advice that is very difficult, if not impossible, for a non-specialist to implement properly.* This is sort of like saying to a flat-earther that of course the earth is not flat, and anyone can find out for themselves if they just get a rocket and fly into outer space. My proposal was more like suggesting a test that someone perform any number of readily available experiments such as looking at the sun set on the ground floor of a high-rise, taking the elevator to the top, and watching it set for a second time. It is something that I know I would not be qualified to do, but which I hoped someone here might be willing to undertake.
*(Similarly, it is misleading when someone says something like 'all amplifiers sound the same' without a great deal of qualification (namely when adequately powered, when the amplifiers are not poorly designed or designed to color the sound, when the distortion level, etc. falls within the required limits, and when the amplifiers are not driven to clipping) they are not helping to educate, but hurting the cause, since there are clear cases when someone moves from, say, an underpowered, cheap AV receiver that was constantly clipping to a higher power/end amplifier which would be able to drive the speakers without clipping or have very different clipping behaviour. In such an instance, it would be impossible to not hear a substantial difference, and even more difficult for the uninformed to avoid falling for other subjectivist lies and snake oil. It is misleading when someone says that the tube sound can be emulated using a DSP without explaining a good deal regarding the different functions of VSTs, the effects of impedance and loads in tube amplifiers on FR, the fact that this will change even between headphones, for example, that are 'rated' as having the same impedance level as one-another if the react as does, for example, the 6XX/650 that is rated 300 ohms nominal but can reach 500 ohms at 100hz, etc, etc.)
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My challenge was in part spawned by my own interactions with a friendly and kind subjectivist on a different forum who strikes me as genuine, kind, wants to be helpful, and engages with people who disagree, but who I believe is a misguided individual who is themselves unwittingly misguiding a whole community of people. I also posed this challenge as a way to get people to explain, in concrete terms, what the functional differences between a tube amplifier would be beyond FR and harmonic distortion (things that can be easily emulated using a couple of free VSTs.)
Moreover, not having the ability to go test gear and being stuck in the house over this last year, I am curious to try out a tube amplifier myself and see if the distortion/coloration would even be to my liking, and faced with a friendly response from an intelligent and earnest subjectivist, I could see how, were I not trained in spotting flaws in arguments, interested in how conspiracy theories and group thinking can manifest, and had I not in the past done a great deal of research into audiophile myths, psychology and psychoacoustics (although I am by no means more than a dabbler compared to some people here) I would have easily been sucked into spending a great deal of money on useless gear and chasing the audiophile dragon.
Someone might just say, 'who cares what these people spend their money on,' but I disagree. If someone wants to spend money on something because it is pretty, that is fine. If someone refuses to listen to reason, there is little one can do. If someone claims, however, that they have experimented with Blind testing, listened to amplifiers or DACs that both measured great but that they could hear a difference, it is impossible to prove them wrong, examine their test setup or measure the gear in question to determine why they perceive a difference when there should not be one. In part, particularly in the past, this was easy to explain (if difficult to warn against) due to the lack of availability of thorough measurements. At this point, however, it appears that while the measurements on this site are useful insofar as they serve to show if there is something fundamentally broken about the equipment in question, this community is seen in some quarters as hostile, closed minded, and dismissive. And I understand why. It is frustrating to have to explain over and over the same points. It is frustrating by those with actual scientific/engineering education, skill, and experience to be questioned in sanctimonious tones by the scientifically and technologically illiterate. It is also, however, easy for group-think and reinforcement of the orthodoxy, even when not entirely accurate to pass unnoticed, and to actually damage the cause. To draw an analogy, people become enraged when a member of the opposed political party presents an uncharitable interpretation of one's own parties' position - they are guilty of straw-manning, or ill informed fools, or liars and shills; when it is a member of our own party, however, we are likely to let half-truths and mischaracterizations of our opponents' positions stand because 'they are on the right side', or 'we know what they mean' or 'they have the essentials right.' Now look back at the posts where someone here responds to a person who claims that amplifiers that measure the same can sound different, etc. Compare how vigorously these claims are attacked and dismissed, and then compare how infrequently and at any rate gently someone who whips out an 'all amplifiers sound the same' without the requisite qualifications, or 'you could just use a DSP/eq' when a question is raised about tubes, is treated. I understand why- human beings like to be in the 'in' group, signal membership using approved terms that are picked up easily and quickly, tend to praise those we see as being on the 'right path' etc. Nonetheless, misinformation is still misinformation, and retreating to our own 'information bubble' is dangerous - see the political landscape (whatever 'side' you belong to!)
Regardless, to educate requires meeting people where they are, rather than where we wish they would be.
) but am not sure where I need to expand, or alternately summarize, my statements.
