Cable Pathways Between Audio Components Can Affect Perceived Sound Quality

[John Dyson]

Unless I misunderstand, this is ONLY an analog experiment, so doesn't directly apply to USB/ethernet/etc type things.   There is a digital interconnect used, but is not part of the experiment.

 

Given this fact, the results become more likely but still I am so skeptical as to not believe it, and currently assume that there was a missing experimental control.   My mind is open, but incredibly skeptical.  The paper will require VERY careful and strict analysis to understand what was measured/compared and VERY VERY precisely undersand the environment.

 

The paper just might be accurate, but the claim/results might be easy to misunderstand.   I am very frustrated that for me, a careful read must wait until after the weekend.   This is 'interesting'...

 

 

 

 

[botrytis]

This is the issue with so many scientific papers being published and so many ways to be published. It is hard to say how well this paper was even read by the reviewers. Little details like the different cable lengths should have been caught in the review process.

[The Computer Audiophile]

I just invited Professor Kunchur to chime in here if he has time. I hope he can. It would be really nice. 

[Qhwoeprktiyns]

3 minutes ago, The Computer Audiophile said:

I just invited Professor Kunchur to chime in here... 

 

Parallel is not completely relevant, but it's an amusing scene regardless. 

 

 

 

[pkane2001]

Fully balanced and single-ended signal paths are sufficiently different internally that any differences could be due to electronics rather than interconnects. The author is, unwittingly, changing too many variables by comparing balanced to single-ended interconnects to make any conclusions about just the interconnects. Different components, different signal path, different processing of the signal between these two cases, possibly different signal levels at the output. All of these are important to eliminate as possible confounds before declaring that interconnects cause the differences. 

 

Also, the fact that balanced vs. single-ended can produce different levels of noise at the output is not surprising, since these were created specifically to deal with noise.

[John Dyson]

2 hours ago, pkane2001 said:

Fully balanced and single-ended signal paths are sufficiently different internally that any differences could be due to electronics rather than interconnects. The author is, unwittingly, changing too many variables by comparing balanced to single-ended interconnects to make any conclusions about just the interconnects. Different components, different signal path, different processing of the signal between these two cases, possibly different signal levels at the output. All of these are important to eliminate as possible confounds before declaring that interconnects cause the differences. 

 

Also, the fact that balanced vs. single-ended can produce different levels of noise at the output is not surprising, since these were created specifically to deal with noise.

Anecdote -- back in the olden days, in NYC, the TV/Radio networks would pass audio signals between buildings/across town with balanced audio cabling.   Of course, the 'art' of doing that has differences from simple local balanced connections, but does show that with proper techniques, balanced connections can do amazing things WRT noise encroaching into the signal.   Also, the balanced signal I/O HW doesnt' have high common mode rejection, there is some lost opportunity for avoiding noise.  The quality of the driving/receiving electronics has major influence on the results.

 

100's of volts of single ended (or common mode in  case of balanced) noise can appear between buildings, the cause substantially being ground potential issues, yet the audio on the TV/radio stations ended up being reasonably clean.  (I am very sure that it wouldnt' be high fidelity by todays standards, but still the SNR was usable.)  Important hint - if grounding the wire shield on long distance balanced connections, do so only on one side...

 

 

 

 

[fas42]

7 hours ago, pkane2001 said:

Fully balanced and single-ended signal paths are sufficiently different internally that any differences could be due to electronics rather than interconnects. The author is, unwittingly, changing too many variables by comparing balanced to single-ended interconnects to make any conclusions about just the interconnects. Different components, different signal path, different processing of the signal between these two cases, possibly different signal levels at the output. All of these are important to eliminate as possible confounds before declaring that interconnects cause the differences. 

 

Also, the fact that balanced vs. single-ended can produce different levels of noise at the output is not surprising, since these were created specifically to deal with noise.

 

I do wonder whether anyone has actually read this paper - just try perusing the Conclusions section, okay?

 

When people have an agenda, all forces that can be applied will be applied, no matter how feeble they are ...

[fas42]

Strangely, the concept is that unless "perfect" integrity is the nature of the chain, that there will be audible differences - in the real world everyone knows this, and it forms the backbone of what everyone does - yet, a formal paper investigates, and puts this in writing, and people fall to the floor in amazement 😉 ... the human condition is quite remarkable to observe, at times ... 🙂.

[pkane2001]

9 minutes ago, fas42 said:

 

I do wonder whether anyone has actually read this paper - just try perusing the Conclusions section, okay?

 

When people have an agenda, all forces that can be applied will be applied, no matter how feeble they are ...

 

Understanding why and how things work is my only agenda, Frank. I understand that you just naturally come by the understanding and knowledge of how things and work and how to improve them. Not all of us are this gifted, so some of us actually need to ask relevant questions. Okay?

 

[PeterSt]

7 hours ago, pkane2001 said:

Different components, different signal path, different processing of the signal between these two cases, possibly different signal levels at the output. All of these are important to eliminate as possible confounds before declaring that interconnects cause the differences. 

 

100%.

But all I know from design is that differential is mainly a pain in the *ss implying more THD than less with SE.

Nicely controversial, right ?

100 pages to discuss ...

 

PS: Strange claim: If you know what can be achieved with balanced, you can achieve the same with SE just by pushing (yourself) harder. For example, common mode noise can also be diminished by eliminating noise in the first place.

So soo many ways to Rome ...

[fas42]

15 minutes ago, pkane2001 said:

 

Understanding why and how things work is my only agenda, Frank. I understand that you just naturally come by the understanding and knowledge of how things and work and how to improve them. Not all of us are this gifted, so some of us actually need to ask relevant questions. Okay?

 

 

No. First step, acknowledge that there is "something going on" - don't apply maximum effort to convince yourself that that you were deluding yourself, by doing measurements until absolutely "nothing to be seen here" - in some parts, they call this being open minded; and they don't let their brains fall out, BTW, when doing so, 😉.

 

The "why" and "how" comes later - accept the WTF'ness of the situation, and proceed with the realisation that something is happening, and should be dealt with ...

[pkane2001]

3 minutes ago, fas42 said:

 

No. First step, acknowledge that there is "something going on" - don't apply maximum effort to convince yourself that that you were deluding yourself, by doing measurements until absolutely "nothing to be seen here" - in some parts, they call this being open minded; and they don't let their brains fall out, BTW, when doing so, 😉.

 

The "why" and "how" comes later - accept the WTF'ness of the situation, and proceed with the realisation that something is happening, and should be dealt with ...

 

Not how science works, I'm afraid. We are discussing a scientific paper that purports to describe a scientific experiment.

[fas42]

Just now, pkane2001 said:

 

Not how science works, I'm afraid. We are discussing a scientific paper that purports to describe a scientific experiment.

 

Love the way you throw in the word, "purports" - ahh, that science find it so easy to rise above the emotions that everyday folk succumb to ... 😜

[The Computer Audiophile]

@fas42 You can no longer post in this specific thread. 

[One and a half]

An objective view is provided by Ethan Winer in this article, that cables do not make a difference using the null method test.

Then again, depends on how good the A/D is and that chain to the sound editor and the capabilities of the software.

 

 

[opus101]

I started watching and paused it once he got into talking about 'beliefs'. A complete red herring.

 

Curiosity got the better of me and I played a bit longer. Had to stop though where he claims 'wire can't add noise'. I take it he's never heard of 'common ground impedance coupling'.

[March Audio]

On 6/11/2021 at 7:24 AM, PeterSt said:

 

100%.

But all I know from design is that differential is mainly a pain in the *ss implying more THD than less with SE.

Nicely controversial, right ?

100 pages to discuss ...

 

PS: Strange claim: If you know what can be achieved with balanced, you can achieve the same with SE just by pushing (yourself) harder. For example, common mode noise can also be diminished by eliminating noise in the first place.

So soo many ways to Rome ...

Not controversial, just simply wrong.

[pkane2001]

55 minutes ago, opus101 said:

I started watching and paused it once he got into talking about 'beliefs'. A complete red herring.

 

Curiosity got the better of me and I played a bit longer. Had to stop though where he claims 'wire can't add noise'. I take it he's never heard of 'common ground impedance coupling'.

Or perhaps he is simply saying that a wire is not an active component and can’t generate noise all by itself. Noise can be introduced from the outside, but not generated by the wire.

[opus101]

7 minutes ago, pkane2001 said:

Or perhaps he is simply saying that a wire is not an active component and can’t generate noise all by itself. Noise can be introduced from the outside, but not generated by the wire.

 

Strictly speaking all wires have resistance so do generate noise 'all by themselves' - but normally that noise is negligible in the context of audio ICs.

 

I haven't watched the video beyond where he said 'wires can't add noise' but his line of thinking leads me to formulate a hypothesis. I am predicting that his testing of wires is not done in-circuit, in which case he'll completely miss the elephant in the room which is the aforementioned common ground impedance coupling.

 

Anyone watched it all and can confirm or deny my prediction?

[opus101]

6 minutes ago, pkane2001 said:

Again, such noise is not generated by the wire but by the circuit the wire is connected to.

 

Not from the circuit in the case of triboelectric effects, no. Its definitely from the insulation over the wire.

 

https://iopscience.iop.org/article/10.1088/0022-3727/20/5/002/pdf

[pkane2001]

1 minute ago, opus101 said:

 

Not from the circuit in the case of triboelectric effects, no. Its definitely from the insulation over the wire.

But still this comes from outside the wire. Other than thermal and 1/f noise the wire isn’t introducing any noise by itself.

[opus101]

Ah maybe we mean different things by 'wire' - I am meaning the whole interconnect, perhaps you only mean the copper conductor part. I shall change to 'cable' in future to avoid such misunderstandings.

 

When I say 'not from the circuit' I don't include cable insulation as part of the circuit. The circuit to me is amps, sources etc.

[March Audio]

To be pedantic (sorry), as mentioned, wires will generate (Johnson) noise, but this is dependant upon temperature and resistance.  In a cable with a resistance of fractions of an ohm this is totally negligible.  Triboelectric noise can be generated by the movement of conductor insulators from vibration or bending.  This generates an electric charge.  A non issue in line level low impedance interconnects, but high impedance sources can be an issue.  Such as electric guitar pickups/cables.  Flick them and you may hear a noise.  Its usually combatted by adding an additional partially conductive layer around the central conductor insulator.

 

This can be a real PITA when doing things like using charge output accelerometers for vibration measurement.  Special, very tightly wound cable and minimising cable vibration helps.  I have very direct experience of this from jet engine testing.

 

However, as I mentioned, in normal low impedance line level interconnects both are a non issue.

[pkane2001]

1 minute ago, opus101 said:

Ah maybe we mean different things by 'wire' - I am meaning the whole interconnect, perhaps you only mean the copper conductor part.

Triboelectric noise is not caused by the interconnect, conductor or insulation. It’s caused by the mechanical motion or vibration coming from outside.

[opus101]

13 minutes ago, March Audio said:

I have very direct experience of this from jet engine testing.

 

Completely OT but I used to design tacho processing for jet engine testing.