The speaker and the room being by far the most variable and influential part of said system.
Every part of a high performance ‘system’ should be considered equally important/symbiotic to the end result.....should it not?
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It may be the case that there are genuine anti ABX evangelists, but I think you will find that the majority of perceived anti ABX'ers are actually nothing of the sort. I have reservations about ABX methodology as do others and this is all to do with experimental error and not anything to do with philosophy. In the case of ABX there are elementary problems with ABX hardware, and in the case of the likes of Foobar ABX there is difference in ABX test audio delivery compared to using Foobar as a plain music player. The experimental error in both examples serves to force null resultant with the conclusion that ABX testing as practiced is useful only for resolving and discriminating relatively coarse differences. If you want to know why I deem that the hardware test is essentially useless for discriminating fine differences please just ask and I will gladly discuss the reasons that this is so. So it boils down to, those who are 'against' trusting the validity of ABX testing do so for technical reasons, and those who advocate ABX are not aware of the technical limitations. If ABX testing was entirely trustworthy then I and many others would be pleased to use ABX testing as absolute truth and there would be no debate.
Stolen from another forum...
Dan.
It's very easy with modern equipment to preserve the signal accuracy to the speaker terminals, after that it's a completely different set of challenges and compromises to get a good result at the ear. This is where "real" psychoacoustics is important.
I don't doubt that he is achieving audible changes in gear by applying shielding/EMR damping etc and without touching a soldering iron but yes I agree it seems his theory knowledge is somewhat askew.
I did some googling and came up with this LinkedIn page which mentions this -
Googling Schulte Research brings up some gems like this.....
I only came up with two patents....something about using a magnetron to heat water to drive a generator system, maybe somebody can find other patents please.
Who cares if he took too much acid in college, maybe he has something novel maybe not, we await Marks audition of the 'improvements'.
Dan.
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I cannot find that quote on the site, however I can tell you my experience with EMI in recording studios: We (the studio design firm I work for) have had to repeatedly remind our clients to not allow cell phones on or near any equipment either in the control or tracking rooms. To this end we establish a "listening" couch or seats at the back of the room where all cell phones must stay.
The presence of a cell phone near equipment, even those which use balanced signal transport can cause clickings and burping noises as the phones communicate with the cells. Perversely the better the shielding in the control room the worse the problem as the phones ramp up output power to compensate. The fix then is to turn the cursed devices off.
We have also had to create actual Faraday cages using copper screening and carbon-loaded paints in areas with high cell-tower radiation. These multi-ISP towers can wreak havoc due to pickup by musical instruments, indeed some such as single-coil guitars make excellent inductive pickups.
My experience with EMI ingress into consumer gear is worse that with pro audio gear. While pro gear often has the pin 1 problem, RCAs isolated from the chassis with their leads to PCBs make great re-radiators inside chassis. Pavel has done a lot of work in this area and can share more on the subject.
As far as reducing EMI generated internally, board layout and grounding methodology is as critical with high-speed digital as it is with switching supplies. I design switching supplies for communications and I can share that small changes in PCB traces with large ΔI/ΔT can reduce broadband 1M radiated EMI levels from a supply by 40 dB or more. Proper design minimizing loop area and isolating these traces from common except at a single bond point can reduce or remove this as a problem. I am unaware of any "technique" to fix these problems after manufacture; installing shields does little if the PCB was not designed to work with the shields.
Perhaps the best example of an attempt to reduce chassis EMI levels I know of was work done at FCRA (Five College Radio Astronomy) on a multi-channel radio telescope IF chassis. Attempts were made to quiet down crosstalk between sealed, machined copper modules linked by rigid SMA cables by strategic use of carbon RF absorbing foam. It did basically nothing, indicating the cause was common-mode currents flowing between modules causing the outside of chassis and cables to radiate. Careful adjustment of driving and terminating impedances was the cure. With this in mind, if the circuitry and/or board design is at fault I am doubtful improvements can be made externally.
Dunno if this adds anything to the discussion...I do find the content on that website vague, speculative and unsubstantiated in general...and as someone who participates in the acoustic design of studios I will say the acoustics page is just a mess.
Howie
Well as someone who has some extensive experience tuning the system to the room I’m gonna say there’s more to it than you concede.
I’ve come to the edge of my particular capabilities but I’m seeing so much more potential upstream and it frustrates me enough to want to expand my knowledge.......just seems taboo to some of you to want ‘better’ instead of ‘good enough’ 😕
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You first need to distinguish between an audio circuit stage approaching RF oscillation, and one suffering from incoming RF interference. These are two quite different scenarios.mmerrill99 said:
An audio circuit stage approaching RF oscillation will almost certainly not show any problems, because it is not oscillating. One suffering from incoming RF interference may work fine, or may have a bias shift which will affect distortion. My point is that any problem will probably not be mediated via the PSU, which is what he appeared to claim.
I was not attempting to explain that a music signal consists of sine waves. I was stating this as a fact, which can be believed or not but it remains a fact. The question then becomes to what extent does a circuit behave differently when fed two or more sine waves rather than just one sine wave? Much of the circuit behaves in exactly the same way, which is why sine wave testing is useful. One difference arises when the frequency difference between two sines becomes small; any difference frequency (i.e. intermodulation) produced by even-order nonlinearity could then be below the usual audio range. This may or may not be a problem, but it is a problem which is within the scope of engineering. The idea that music is somehow fundamentally different is persistent but it has no basis in reality.
I was not seeking sympathy or points. I was trying to get you to think. Where do you think these measurements came from?
Why do you often play the alchemist, ignorant (or perhaps even dismissive) of chemistry?
So a small change can be so huge that it can easily be spotted when you believe it is present, but so small that it can't be detected when you don't know if it is there? This is supposed to be superior to electrical measurements? I note that these huge changes can sometimes be heard when they are not present simply because the listener has been told (perhaps implicitly) that they are present.
When you read Toole it can be quite surprising what is good enough, he has done numerous studies and listening tests into the psychoacoustics of speakers in rooms.
This gives me a half-baked idea for a product:
It seems one could make a "power supply isolation box" with whatever filtering one would need at its power input, that generates a low-distortion 60Hz (50Hz if you want to run your equipment on "Pure European" power) output at 120V or 240V however many hundred watts one wants. It could even have a battery to supply power during short outages. Yes, this look a lot like a UPS as used with computers, but it has "better specs."
This could be made and sold for significantly less than the power "cable" I was just looking at, and perform better as well. It would (also) be marketed to the industrial and lab market to get a decent market size. I would think such products have replaced those huge ferroresonant transformers used for voltage regulation, but I see Sola is still around.
Some people would still spend more on power cables that give less result.
I was just looking at the PS Audio power cables, and ...
It seems one could make a "power supply isolation box" with whatever filtering one would need at its power input, that generates a low-distortion 60Hz (50Hz if you want to run your equipment on "Pure European" power) output at 120V or 240V however many hundred watts one wants. It could even have a battery to supply power during short outages. Yes, this look a lot like a UPS as used with computers, but it has "better specs."
This could be made and sold for significantly less than the power "cable" I was just looking at, and perform better as well. It would (also) be marketed to the industrial and lab market to get a decent market size. I would think such products have replaced those huge ferroresonant transformers used for voltage regulation, but I see Sola is still around.
Some people would still spend more on power cables that give less result.
Those are already available as commercial products. The cheaper models are phase-locked to the mains frequency. The more expensive ones let you dial up whatever frequency you wish, within a range. Maybe you'll prefer the sound of your Krell amplifiers running on 61.3 Hz rather than 60 Hz? Who knows, the only way to find out is to give it a try. Many of them offer several different output waveshapes besides mathematically pure sine waves. You know, to increase the conduction angle of the rectifiers and to smooooooth out that nasty switch-off transient when diode current abruptly falls below zero. Tube guys used to call it "Reverse Recovery Snapback Filtering" and the like.
Thank you for bringing some practical engineering concerns to the discussion. In addition to what you just said, it is well known that certain opamps are more sensitive to RF than others. LME49720, LME49860, etc., show FFT spurs when un-shielded and in the vicinity of a DECT phone base station, for example.
Speaking of Benchmark DAC-3 in particular, it does use LME49860 opamps. However, it appears to have been designed with careful consideration of shielding requirements. For example, the case is steel, IO connectors are grounded to the case, and ferrites are used on signal lines between IO connectors and the PCB.
EDIT: Change of subject for a moment: Dan, there appears to be more than one guy with the same name. The real patents appear to be held by another person, not the person being discussed here.
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So, a taste test example where a good measurable difference was presented and the proportion of correct answers was 0.92 in an A/B (paired comparison) but only 0.60 in the ABX run (same group of participants) is not sufficient?
Which basically means, that the internal decision strategy differences - triggered by the different test protocols - in a miraculous way can only happen for the taste sense but not for the listening sense?!
I have found 50Hz playback power works best for 50Hz recordings and 60Hz playback power best for 60Hz recordings with 55Hz optimal all round.
Dan.
Are the ferrites removable ?.....if so I would try the experiment of running the DAC without the ferrites.
I have run loopback recordings of same line cable with or without clip-on ferrites and the difference is strongly audible, and disagreeably so imo, just saying.
It might be interesting to read about his 'patented replacements for nuclear coal gas power'.
I have no idea of how to do so, please tell me how to do this ?.
Dan.
So there's a real person with patents for working fusion power, as per Max's quotes? 😀
Mind you, patent offices have been known to allow absurd things.... Like perpetual motion.
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I have seen ferrites that do cause a problem as you describe and those that do not. It appears to depend on the type of ferrite material, among other factors.
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Fair comment, any idea of the ferrite formulation type numbers ?.
Is this the inside of your DAC-3 ?
Dan.
Maybe it's the language barrier but you may want use "well" or "poorly" designed amp because when you say wrong design, it would mean something that wouldn't work at all.
I think you are confused about how it was explained by some. Good amps should be audibly transparent within the designed range of operation.
Doesn't jkeny's DAC make your list to try? It says, "By avoiding pre-ringing a more detailed, dynamic & natural sound is produced."
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