Why Tweaks Change the Sound ...Mystery Solved

D

Dmance

Audiophyte
I run AUDIOWISE.CA - which I started to get to the bottom of many of the mysteries I heard with 2-channel digital audio. Notably those involving the audible impact from components/cables/tweaks which 'common-sense' (and the laws of physics) indicate are impossible. Some of these are:
- digital components upstream of a DAC impact sound
- digital cables impact sound
- power cables impact sound (both upstream and downstream of a DAC)
- signal (USB/Ethernet) regenerators/reclockers impact sound
- etc.

Gene has gone here many times on his YouTube channel - where he takes the absolutist view to claim that personal impressions of SQ changes must be mistaken when there is no physical mechanism possible. Of course, he is right, the textbook definition of 'digital communications' is the reliable transfer of information in the presence of noise. So, yes, the DAC always gets a 100% faithful bitstream from upstream components regardless of those tweaks. Yet ...with a highly resolving transducer (headphone/speakers) the changes in SQ are quite apparent. And I am referring to the loss of staging, depth, details and sense of realism that perhaps is in the last 10% of SQ ...but makes music so much more engaging.

So this is the big mystery: the bitstream is perfect all the way to the DAC ...yet the sound changes. Here I will make the following assertions:
- where it all matters for SQ is at the DACs final D/A stage: stable reference voltages and reliable clocking of output samples
- we have seriously underestimated the impact of RF (radio frequency) noise impact on the above
- we don't yet fully understand how our ear/brain gets affected by impossibly small deviations in above to detract from totally engaging and fatigue-free listening

...and here is how to understand what is going on:
- anything with a digital clock (FPGA, Integrated Circuit, CPU, etc.) can induce wideband RF Noise (MHz to GHz range) which conducts or radiates to the DAC
- any metal conductor (signal or power cable) is a culprit here for direct galvanic conduction of RF noise or to act as antenna
- cables with differing construction or metallurgy vary only in their ability to filter RF noise or in in their efficiency as an antenna
- an amalgam of digital tweaks which changes/improves the sound only does so by altering the RF emissions spectrum
- RF noise can migrate via radiated, conductive or inducted means to cross free-air distances inside component chassis or between chassis
- RF noise can migrate from a digital device back through power supplies to the AC mains and into the wall wiring to affect other AC connected components
- DACs themselves emit RF noise (out of band noise) at their outputs. This too can get amplified by downstream amplifiers and radiated into the environment by power cables
- Distancing a DAC away from upstream digital components helps transparency.
- Using optical signal where possible helps transparency

This is my first Audioholics post. I will follow up with specific remedies for specific configurations and I welcome user requests and questions. My philosophy and approach will allow you to reach end-game SQ. More importantly ...you will be doing so with a full and complete understanding of why you are making changes and how they are addressing a problem.

Dan
 
Swerd

Swerd

Audioholic Spartan
I see a lot of claims about what can improve sound quality, but I see no evidence to support those claims.

How did you measure the sound qualities of the various components you mentioned, digital components upstream of a DAC, digital cables, power cables, and signal (USB/Ethernet) regenerators/reclockers?

Unless you provide convincing evidence to support your claims, you won't get much attention here. And let me say it clearly – convincing evidence about sound qualities must include listening tests. Electronic lab bench test results alone cannot tell us whether we can hear differences in sound qualities.

These listening tests must be done while listeners are blind to what equipment is operating. These blind listening tests must be done properly according to scientific understanding of tests of human sensory perception, with large enough numbers of listeners to achieve statistical significance, and with appropriate negative and positive controls.
 
D

Dmance

Audiophyte
I see a lot of claims about what can improve sound quality, but I see no evidence to support those claims.

How did you measure the sound qualities of the various components you mentioned, digital components upstream of a DAC, digital cables, power cables, and signal (USB/Ethernet) regenerators/reclockers?

Unless you provide convincing evidence to support your claims, you won't get much attention here. And let me say it clearly – convincing evidence about sound qualities must include listening tests. Electronic lab bench test results alone cannot tell us whether we can hear differences in sound qualities.

These listening tests must be done while listeners are blind to what equipment is operating. These blind listening tests must be done properly according to scientific understanding of tests of human sensory perception, with large enough numbers of listeners to achieve statistical significance, and with appropriate negative and positive controls.
Sure ...l am just getting started. Buy you could say that that evidence of the opposite is evidence that that there must be mechanism at play. Regarding USB/Ethernet re-clockers: there must be thousands (perhaps 10's of thousands) sold to satisfied customers who hear a difference. Here is your large sample size listening test ...despite the fact that DACs all now reclock and so there is no bitstream mechanism to explain the reported improvement in SQ. Are they all deluded? Are you going to discount their listening impressions? If you are honest and pragmatic about finding an answer you have to look outside the bitstream ...and this is the domain of analog RF noise.
 
killdozzer

killdozzer

Audioholic Field Marshall
John 9:25

"One thing I do know. I was (doing double) blind (test) but now I see!"
 
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Pogre

Pogre

Audioholic Warlord
Sure ...l am just getting started. Buy you could say that that evidence of the opposite is evidence that that there must be mechanism at play. Regarding USB/Ethernet re-clockers: there must be thousands (perhaps 10's of thousands) sold to satisfied customers who hear a difference. Here is your large sample size listening test ...despite the fact that DACs all now reclock and so there is no bitstream mechanism to explain the reported improvement in SQ. Are they all deluded? Are you going to discount their listening impressions? If you are honest and pragmatic about finding an answer you have to look outside the bitstream ...and this is the domain of analog RF noise.
This large sample size listening tests of satisfied customers you're referencing (all of whom are susceptible to placebo and expectation bias), these were DBT listening tests performed under conditions described by @Swerd?
 
D

Dmance

Audiophyte
This large sample size listening tests of satisfied customers you're referencing (all of whom are susceptible to placebo and expectation bias), these were DBT listening tests performed under conditions described by @Swerd?
Well they were performed under conditions of cash or credit. :) which has some validity. ...But to your point, I am looking for willing participants to test my RF-STOP Cable Sleeve. This is a full length RF isolation sleeve that pulls over any 2-meter power cord - particularly the amplifier. Jaw dropping change in sound ...to the good. Why? Because it stops the power cord from acting like an antenna and thus less RF noise impinges on the DAC. This will satisfy all those who understand that the last few feet of a power cord cannot change the power delivery to an amplifier ...but what you have is a tethered metal conductor with a galvanic link back to a source of RF noise.

In this business, the testimony of trusted individuals is very strong ...so if I can get 10 Audioholics (of good standing and influence) to provide honest feedback, this may have more benefit than several DBTs. If interested in helping me test (no cost or commitment of course) please PM me!
 
Swerd

Swerd

Audioholic Spartan
Sure ...l am just getting started. Buy you could say that that evidence of the opposite is evidence that that there must be mechanism at play.
That doesn’t make any sense, much less hold any water. Evidence of the opposite doesn’t become evidence for or against anything. It may be one of several possible explanations, but it could also be a wrong explanation.
Regarding USB/Ethernet re-clockers: there must be thousands (perhaps 10's of thousands) sold to satisfied customers who hear a difference. Here is your large sample size listening test ...despite the fact that DACs all now reclock and so there is no bitstream mechanism to explain the reported improvement in SQ. Are they all deluded? Are you going to discount their listening impressions?
If there are thousands or more customers who hear a difference, then it will be very easy to do a real listening test to provide convincing support. Those thousands of customers, who you claim are satisfied, are anecdotal evidence, “considered the least certain type of scientific information. Researchers may use anecdotal evidence for suggesting new hypotheses, but never as validating evidence.” The testimony from those customers can’t come close to results from a scientifically controlled listening test.
If you are honest and pragmatic about finding an answer you have to look outside the bitstream ...and this is the domain of analog RF noise.
I am being honest and pragmatic about this. I wish you would also. If a digital bitstream can be affected by introducing analog RF noise – that is audibly noticeable to blinded listeners – then you should be able to come up with a scientifically valid way to demonstrate that.
 
D

Dmance

Audiophyte
@Swerd
I understand and accept all your feedback. A proper and rigorous DBT (or several) lets me plant a flag to the claim that analog RF noise produced by digital devices does change the sound. FYI, I don't mean to say that the bitstream gets modified at all. Its 100% intact all the way. What I propose is the DAC gets the bump and grind from RF noise with sufficient energy to affect the final D/A conversion. So the energy levels impinging on the DAC are sufficient to perturb the crystal clock that times the output and also perturbs the reference voltage and ground level. So this causes the audible differences. This is my hypothesis ...and yes, to be taken seriously I need the DBT...and I am asking for help from the open minded.
 
Pogre

Pogre

Audioholic Warlord
Well they were performed under conditions of cash or credit. :) which has some validity. ...But to your point, I am looking for willing participants to test my RF-STOP Cable Sleeve. This is a full length RF isolation sleeve that pulls over any 2-meter power cord - particularly the amplifier. Jaw dropping change in sound ...to the good. Why? Because it stops the power cord from acting like an antenna and thus less RF noise impinges on the DAC. This will satisfy all those who understand that the last few feet of a power cord cannot change the power delivery to an amplifier ...but what you have is a tethered metal conductor with a galvanic link back to a source of RF noise.

In this business, the testimony of trusted individuals is very strong ...so if I can get 10 Audioholics (of good standing and influence) to provide honest feedback, this may have more benefit than several DBTs. If interested in helping me test (no cost or commitment of course) please PM me!
Jaw dropping, huh? Well that means it's gonna be super easy to tell in a DBT then. Sure I'm willing to to participate in a DBT, absolutely. I think you should as well.
 
NINaudio

NINaudio

Audioholic General
So, you know that none of this stuff is used or even considered for use in high energy physics where there are tiny tiny signals being searched for around lots of equipment generating huge magnetic and RF fields. What do they use? Cable with standard insulation and known RF rejecting properties. Not something that costs $100/ft, unless it's either: A) really really thickly copper cored (we've got some 6" thick coax cables to feed some of our RF amplifiers). or B) came from nuclear test sites and is extensively radiation hardened.

Had you actually read anything on this site, you'd have realized you're barking up the wrong tree here with your general assumptions and hearsay based "evidence".
 
mtrycrafts

mtrycrafts

Audioholic Slumlord
Sure ...l am just getting started. Buy you could say that that evidence of the opposite is evidence that that there must be mechanism at play. Regarding USB/Ethernet re-clockers: there must be thousands (perhaps 10's of thousands) sold to satisfied customers who hear a difference. Here is your large sample size listening test ...despite the fact that DACs all now reclock and so there is no bitstream mechanism to explain the reported improvement in SQ. Are they all deluded? Are you going to discount their listening impressions? If you are honest and pragmatic about finding an answer you have to look outside the bitstream ...and this is the domain of analog RF noise.
How do you know these 10s of thousands heard a difference? Did you or any credible tester performed credible tests on them or are they just self reporting?

Did you know there is a difference between hearing and perception? Placebo? Bias? You have a way to go to be taken seriously. Especially when you seem to be peddling this RF-Stopper nonsense.

But hey, there are lots of suckers out there for this kind of nonsense.
Have you tried AA forum? They would love to test you RF-Stopper, lots of willing subjects.
 
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Pogre

Pogre

Audioholic Warlord
So, you know that none of this stuff is used or even considered for use in high energy physics where there are tiny tiny signals being searched for around lots of equipment generating huge magnetic and RF fields. What do they use? Cable with standard insulation and known RF rejecting properties. Not something that costs $100/ft, unless it's either: A) really really thickly copper cored (we've got some 6" thick coax cables to feed some of our RF amplifiers). or B) came from nuclear test sites and is extensively radiation hardened.

Had you actually read anything on this site, you'd have realized you're barking up the wrong tree here with your general assumptions and hearsay based "evidence".
What do you know? Just because you work at CERN, the largest particle physics lab on the planet where they spend their days looking for neutrinos using super ultra sensitive SOTA equipment doesn't mean anything. You guys are using regular unshielded power cords!!

No wonder you haven't found dark matter yet... pft.

:p
 
mtrycrafts

mtrycrafts

Audioholic Slumlord
...

In this business, the testimony of trusted individuals is very strong ...so if I can get 10 Audioholics (of good standing and influence) to provide honest feedback, this may have more benefit than several DBTs.
So, you are in business then?
Trusted individuals? Based on what? Trusted how and why? Being honest in their response? Of course they would be but that is not the right criteria for gathering evidence.

It seems you just don't understand human psychology, perception, bias, placebo, and credible evidence.

As to benefit? Perhaps to you and business but not being honest as the evidence is worthless from such feedback. And, no, it has no benefit no matter how many such feedback over credible DBT testing.
Seems like another snake oil claims.
 
Pogre

Pogre

Audioholic Warlord
So, you are in business then?
Trusted individuals? Based on what? Trusted how and why? Being honest in their response? Of course they would be but that is not the right criteria for gathering evidence.

It seems you just don't understand human psychology, perception, bias, placebo, and credible evidence.
I'll volunteer. He's offered to send me the product, free of charge and asked for contact info. I'm verifying with him in a pm right now. He's open to doing DBT. I'll give him credit for that. It's more than we normally get from the woo-woo crowd.
 
mtrycrafts

mtrycrafts

Audioholic Slumlord
I'll volunteer. He's offered to send me the product, free of charge and asked for contact info. I'm verifying with him in a pm right now. He's open to doing DBT. I'll give him credit for that. It's more than we normally get from the woo-woo crowd.
Yes, but why is he not setting it up himself? After all, 10s of thousands are willing subjects.

Oh, wait, perhaps not when they know it is a closed book test. :D
 
mtrycrafts

mtrycrafts

Audioholic Slumlord
The mystery is actually not solved. Evidence is missing. Speculation is not evidence.
 
D

Dmance

Audiophyte
So, you are in business then?
Trusted individuals? Based on what? Trusted how and why? Being honest in their response? Of course they would be but that is not the right criteria for gathering evidence.

It seems you just don't understand human psychology, perception, bias, placebo, and credible evidence.

As to benefit? Perhaps to you and business but not being honest as the evidence is worthless from such feedback. And, no, it has no benefit no matter how many such feedback over credible DBT testing.
Seems like another snake oil claims.
Please grant me the benefit of the doubt. I may be onto something. You can stand on the sidelines or PM me if you want to get involved.
 
S

Speedskater

Audioholic Chief
In the past many have been granted the benefit of the doubt. But when it comes time to demonstrate their finding they find some excuse to not finish their project.
 

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