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Thread: At What Point Does Reducing Electrical Noise Reach No Audible Difference?

  1. #46
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    Red face

    Quote Originally Posted by Mr. Widget View Post
    Unbelievable perhaps, but I really have no idea what you are getting at.

    FWIW: The only claim I made was that we need to follow Harman's lead and use blind/double blind testing if we want valid human feedback.

    My premise that sighted bias was the reason the Stereophile reviewers came to their conclusions could be wrong, but I think we all need to open our minds to the possibility that we have been fooling ourselves for years about what is and is not an audible improvement.

    I hope to have more clarity on this in the coming weeks.


    Widget
    This is a lengthy post because there are a number of facets that warrant further consideration:

    1. There is no uniform standard for how we listen to equipment and express what we here.

    I agree that sited bias ( listening with our eyes) can play an influence on what people think they hear. This can start a domino effect when a group of listeners share their perceptions. We love symmetry and images that symbolise certainty or other emotional reassurances.

    Our Asian hifi friends often refer to scepticism or cynicism of their auditory perceptions when they sit down in front of a hifi system they aren’t familiar with. This also tends to occur after unboxing and setting up a new component when it doesn’t visually appeal to them.

    2. The Product Marketing of HiFi equipment is quite diverse across brands and equipment ranges. This is another influencer in how we judge or pre judge audio equipment.

    Exotic loudspeaker and interconnect cables are a classic example of snake oil marketing. Don’t blame you amp purchase when you can modify the sound with a cable. This is when things get decidedly murky.

    But then there are more honest advances in sound reproduction based on science and more to the point excellence in the design and execution of fine audio equipment.

    Examples of this are Hegal and Nad. Both are understated brands with their core about what goes on inside the product.

    The key is to know when the marketing department are taking these developments a bit too far with bold claims.

    Examples of this might be Marantz and Luxman brands. Their approach to artisan industrial design and flashy descriptions of circuit innovations seem too good to be true. Their products tend to present a coloured view of the original recording. But some people like that all the same. That raises another whole discussion on niceties of sound reproduction. Should HiFi equipment translate only the original recording or should it make the recording more enjoyable to listen to? Based on sales l think Marantz have their market cornered.

    3. Value Added Product Upgrade Marketing and Engineering Insights.

    Back to the Naim power supply thing Naim have been advocating power supply upgrades for literally decades. I think this is in part their approach to product marketing “you can always improve on good, better and best”.

    But logically why not do it right the first time?

    For technical implementation reasons the blameless power supply is often a compromise when placed in a single chassis product.

    Physical transformer noise, magnetic interference, rectifier noise and mains line noise to name a few are very difficult to deal with in a single chassis.

    Most recently Texas Instruments have demonstrated they can now put a switch mode power supply into a very tiny chip which emits very little noise. They literally rewrote the book on the physical design of SMPS.

    Without going off the deep end any toroidal or iron core transformer has major issues once placed inside a single chassis. Heavy shielding, C Core transformers and elaborate filtering and regulators can get the noise down but at a significant manufacturing cost and added weight to the product. Products with both digital and analogue processing add further complexity.

    This also impacts on pcb design and layout which can easily result in compromising the implementation of audio circuits. The layout of audio circuits is as much an art as it is a science to obtain the theoretical perfect performance. This ultimately means freeing up space inside the chassis. So without compromising the internal chassis layout an external power supply is the alternative. Audiophiles take this as a thumbs up to the ultimate. But not all customers have room for a two chassis component. This causes a lot of head scratching in the R&D Lab when engineers, accountants and the marketing department sit down to conceptualise a product.

    Some good examples of this are the Sutherland phono preamps. Ron Sutherland was once involved high precision equipment for other industries so he thinks beyond just it’s a HiFi component.

    The Vendetta preamp is another example of a no compromise design.

    A separate power supply adds considerable cost due to fabrication, hardware, parts and labour not to mention adding to freight costs. The $5000 component now becomes the $8,000 component. The HiFi reviewer is frothing that it must sound better. But in what way or how much better really is it? Can the improvements be picked up in a snap shot double blind test? Or will the differences take time to establish once the ear and the brain un learn and re learn what it’s decoding? Or is the siting of a new component the trigger for unlearning and re learning? Food for thought.

    4 The Law of Diminishing Returns

    There is also the principle of diminishing returns and unfortunately hi end audio is prone to playing the pointlessly over build product as a ploy to attract big spenders.

    Examples of this are the Dan Agostino’s latest amplifiers. These products are unaffordable except for the minority that includes Dentists, Surgeons and stock brokers on Wall Street. Their prowess and egos crave for examples of over the top spending that has no rationality.

    5. Are Double Blind Tests always the only perceptual measure of differences in sound reproduction??

    On the double blind tests l believe the validity of such tests really depends on the threshold(s) and types of audible differences we are attempting to discern? The human ear and the brain are not rational in the sensitivity to all aspects of decoding and thresholds so it’s grey area unless your Greg Timbers or someone like that. These highly skilled engineers with decades of experience understand what people listen for, their likes and their dislikes. Earl Geddes has shared some of his findings in books he has authored and in online discussions with the diy loudspeaker community.

    Both Toole, Oliver and and other researchers acknowledge this and they hold their closer to their chests than they let on. There’s a lot more too it than meets the eye.

    Are the differences in the frequency domain, time domain, amplitude domain, phase domain. Are these random artefacts or constant aberrations at the audible frequency extremes. When this is a guessing game you have hifi buffs regularly swapping out equipment.

    Are the listeners trained or un trained. Is the room acoustically treated or not?

    It’s generally acknowledged that how people hear or interpret sounds varies. So who is right and who is wrong? This is acknowledged across geographic regions around the world.

    Conclusion
    So it’s a bit of pot luck to make an accurate judgement against what any one person or a listening group says they hear and don’t hear. This post attempts to explore some of the more interesting aspects of how we think about and listen HiFi equipment.

    All that matters is what you hear in the moment.

  2. #47
    Administrator Mr. Widget's Avatar
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    Hi Ian, thank you for your more thoughtful post where we seem to have less distance between us.

    My underlying reason for the blind test is that sometimes we listen to a piece of gear and hear magic that fades with time. I believe the magic was never there, but due to our biases seeing the pretty big blue meters, the glowing tubes, the massive machined aluminum chassis or whatever created an expectation that our mind fulfills.

    To avoid this possible eventual disappointment I propose using blind tests to evaluate a potential purchase or change. I am questioning the validity of our more typical comparisons where we make no attempt at balancing levels and like Stereophile we know the devices under test. While implementation may not be that simple, the concept is.

    Quote Originally Posted by Ian Mackenzie View Post
    All that matters is what you hear in the moment.
    Exactly!

    Widget

  3. #48
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    Quote Originally Posted by Mr. Widget View Post
    Hi Ian, thank you for your more thoughtful post where we seem to have less distance between us.

    My underlying reason for the blind test is that sometimes we listen to a piece of gear and hear magic that fades with time. I believe the magic was never there, but due to our biases seeing the pretty big blue meters, the glowing tubes, the massive machined aluminum chassis or whatever created an expectation that our mind fulfills.

    To avoid this possible eventual disappointment I propose using blind tests to evaluate a potential purchase or change. I am questioning the validity of our more typical comparisons where we make no attempt at balancing levels and like Stereophile we know the devices under test. While implementation may not be that simple, the concept is.

    Exactly!

    Widget
    Thank you for elaborating and substantiating on your position and illustrating listening sessions with Todd.

    I can see where you’re coming from.

    In terms of the magic that fades with time l have never consistently experienced that myself. The only time my experience has gone backwards is when l inadvertently made a mistake with reconnecting the complex wiring of a multi way system.

    I agree product bias can influence a listeners emotional acceptance before hearing a piece of equipment particularly if they have read a review.

    I am not aware of the specifics of how the Stereophile listening was done. Therefore my position is it’s inappropriate throw out the listening experience of a group particularly when being made aware of the objective testing. There is no direct correlation proven or otherwise to associate one objective measurement with the listening experience of a group of people.

    This is because what each listener may value, enjoy or like may have nothing to do with what the objective test identifies. But when a piece of equipment measures well and is subjectively well received the design is valid. The problem here is l think you looked at the measurements and then ruled out the listening groups subjective assessment because you didn’t believe it. That’s your opinion but it doesn’t mean the listening groups finding are invalid.

    You were biased by your own listening experiences and understanding of site bias as you refer to so you made the assumption it was invalid (Respectfully).

    In consideration of the above three paragraphs your reasoning is therefore flawed.

    On your point of balancing levels l agree that is important when comparing equipment.

    It’s not impossible to do and l have been involved in such listening comparisons with interconnects. The result was red faces from owners of $1000+ cables.

    My experience is that a system can really lock in and elevate the subjective performance when absolute symmetry is achieved in listening levels on both left and right loudspeakers.

    As l outlined above aspects of equipment design such as pcb layout can definitely include the subjective performance. Vibrations can also affect performance. I once tapped a solid state no stage pcb and l could hear it through the loudspeakers. Go figure. Changing out transistors for higher spec versions and matching can also be subjectively audible. Parts age including semiconductors and it’s no surprise servicing a 15 year old piece of equipment can put a smile on the owners face.

    The Musical Fidelity A1 integrated amplifier was an excellent low powered Class A design that won many awards. But due to heat inside the chassis the design was unreliable. The designer didn’t account for the aging of the parts.

    Enjoy your Christmas Day.

  4. #49
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    On compassionate grounds it’s normal to go through stages of latency with any hobby as long as you spring back. Sometimes personal stuff or changes in life can cause disinterest in the most enjoyable things in life. I find taking a break from it all helps to refresh. Life can get in the way of taking a break but with some persistence l did get away for a tour of far West Queensland this year. Sometimes reaching out verbally to discuss the hobby in detail help restore enthusiasm.

  5. #50
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    Widget

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    I ordered a pair of Mundorf EVO Oil 4.7 mfd ($17.50/each) caps for the Heils. These are/were to replace the 4.7 mfd Audyn Q4 caps ($4.34 each) currently in place. I had previously tried a 4.0 oil can with a 0.69 ClarityCap piggybacked for 4.69 mfd, set up A/B against the Audyns to see if I could reliably A/B a difference. Widget had his doubts.

    I replaced the oil can/Clarity with the Mundorf, still set up A/B with the Audyn, and have been listening for a few days. Yeah you've heard it before..., the Audyn sounds "as if a veil is being lifted" when switched into the circuit. This gives the music more air and edge, but it is as if this additional air can carry a glare or grit less pronounced with the Mundorfs.

    Also, the Audyns "drive" the Heils harder and can sound a bit "forced" depending on the medium. The Audyns test at 4.66 and 4.77 mfd while the Mundorfs test at 4.78 and 4.79 mfd, so the 5% Audyns are actually closer to spec than the 3% Mundorfs.

    The question then arises, is the Audyn cap creating this grit/glare, or just exposing it from the upstream electronics, including that used in the entire recording chain?

  7. #52
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    I think that most anyone with good hearing could instantaneously A/B the difference, but if one had to change things out even for a few moments..., that's a totally different matter. Long term listening would reveal a difference.





    https://youtu.be/z8ICkSkgie4

  8. #53
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by toddalin View Post
    I think that most anyone with good hearing could instantaneously A/B the difference, but if one had to change things out even for a few moments..., that's a totally different matter. Long term listening would reveal a difference.
    Do you measure at least a difference of 0.2dB over a band of frequencies?

    EDIT: I just noticed your YouTube link. Kinda hard to judge the difference with such a coarse resolution. Is that maxed out or can you get higher resolution readings. Also, when using pink noise, I like to average 30 or 60 seconds of signal to get a stable solid number. It is impossible to get a really accurate instantaneous reading with a pink noise signal.
    Are you comparing the 4.77 Audyn to the 4.78 Mundorf?


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  9. #54
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    Quote Originally Posted by Mr. Widget View Post
    Do you measure at least a difference of 0.2dB over a band of frequencies?

    EDIT: I just noticed your YouTube link. Kinda hard to judge the difference with such a coarse resolution. Is that maxed out or can you get higher resolution readings. Also, when using pink noise, I like to average 30 or 60 seconds of signal to get a stable solid number. It is impossible to get a really accurate instantaneous reading with a pink noise signal.
    Are you comparing the 4.77 Audyn to the 4.78 Mundorf?


    Widget
    Very easy to see the display rise/fall ~1 dB as well as the dB level meter. The entire display is 15 dB (30 dB is typical) with 2.5 dB between lines (5 dB is typical). The tripod would not support the weight of the camera, so the image is looking up at an angle, hence the keystone distortion.

    The 4.77 Audyn is paired/compared to the 4.79 Mundorf. The 4.66 Audyn is paired with the 4.78 Mundorf. In theory, the Mundorfs should have let just that much more signal through, yet the Audyns are clearly louder, brighter, more sibilant, more cymbol, more hash, etc.

    I guess what it comes down to is that different caps exhibit characteristics beyond their mfd.

    I had considered that in a timing circuit (e.g., 555 chip), cap construction really makes no difference and it does come down to mfd. But a timing circuit is based on that portion of the charge cycle where a cap exhibits a linear charge/discharge rate (36% - 63% or something like that IIRC) and who knows what a cap really takes the remainder of the time? When I fire up my 555 devices on my garden railroad, the first cycle always takes much longer when the cap starts from nothing.

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    Hello Toddalin

    Well you have an oil vs a film cap??? Different construction. You have the oil cap attenuating the signal compared to the foil?? Do the oil caps have a higher ESR rating??

    ESR = equivalent series resistance

    Rob
    "I could be arguing in my spare time"

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    Quote Originally Posted by toddalin View Post
    Very easy to see the display rise/fall ~1 dB as well as the dB level meter. The entire display is 15 dB (30 dB is typical) with 2.5 dB between lines (5 dB is typical). The tripod would not support the weight of the camera, so the image is looking up at an angle, hence the keystone distortion.
    To get really useful measurements you really should get a phone app or REW on your computer. The RTA tech you are using was SOTA 40 years ago, but today for virtually no cost you can get much more accurate and higher resolutions measurements.

    Quote Originally Posted by Robh3606 View Post
    Hello Toddalin

    Well you have an oil vs a film cap??? Different construction. You have the oil cap attenuating the signal compared to the foil?? Do the oil caps have a higher ESR rating??

    ESR = equivalent series resistance

    Rob
    Yes, that would appear to be the case. To know if there is any difference in sound quality between the two caps, one would need to adjust the padding.


    Widget

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    Quote Originally Posted by Robh3606 View Post
    Hello Toddalin

    Well you have an oil vs a film cap??? Different construction. You have the oil cap attenuating the signal compared to the foil?? Do the oil caps have a higher ESR rating??

    ESR = equivalent series resistance

    Rob
    Would you, or anyone, have expected a difference of ~1 dB, as well as a different frequency balance, just due to a cap change with the same value? Have you EVER seen a cap comparison where they discuss the resultant measured volume change?

    Would anyone even know how to translate an ESR to an overall volume changes? Both caps are listed as having extremely low ESR values.

    https://www.parts-express.com/Audyn-...114?quantity=1

    https://www.madisoundspeakerstore.co...oil-capacitor/

  13. #58
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    Quote Originally Posted by toddalin View Post
    Would you, or anyone, have expected a difference of ~1 dB, as well as a different frequency balance, just due to a cap change with the same value? Have you EVER seen a cap comparison where they discuss the resultant measured volume change?
    Nope, but I haven't paid much attention to people's cap reviews on the inter web.

    I agree it is surprising that you are seeing such a substantial output differential. The frequency change would most likely be due to the added R in the crossover. Rob or Ian could use LEAP to model different series R to see what difference is required for this change.
    If we were really curious PEAK makes an ESR meter that DigiKey sells for about $100.


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    Very Cool!! A new capacitor thread for the incoming New Year ( & I'm not being intentionally facetious ).

    Todd, I'm curious, what sort of Motor-Run cap are you referring to ( Oil-Can as you call it ) ??
    - PIO ( Paper in Oil ) or the more modern MPP in Oil ( Metallized PolyPropylene in Oil ) ??

    To see if you can reduce the inherent HF hash that you're experiencing from the Audyn's Q4, give it some DC voltage for a day ( let it act as a battery for 24-48 hours so that the windings can swell and tighten-up somewhat ) >> use 18volts ( or more ) derived from some 9Volt batteries.
    - Just make sure that you fully discharge that capacitor before putting it back into the HF circuit ( we don't want to hear about you damaging those nice AMT's ).

    Tightening the capacitors windings can noticeably reduce some of the UHF hash ( also sparkle ) since these small inconsistencies in the winding tension can act like a mechanical generator for High-Q resonances
    ( offering an effect much like the
    Aphex Aural Exciter and how it was initially used in Studio Work starting way back in the late 1970's )

    Just be aware, any capacitor ( that I've done this to ) never returns completely back to it's ( like-new, "fresh off the line" >> sparkly ) state .

    Consider the DC treatment a form of accelerated capacitor "break-in" .


    PS >> Happy New Year!!

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    When I was comparing the other Heil, the volume and spectra between caps were much closer, within a couple 10ths of a dB. When I switched the caps and aagain tested this side to see if one was wonky, the results didn't change.

    When I went back to the other side, (in the video), and switched the test wires between the caps the louder volume still followed the Audyn. Weird.

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