It *cannot* just be about 1's and 0's - surely?

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2 hours ago, Mazza said:

Yes, USB cables are a contentious subject but bear with me please! ?

 

So, I have just swapped my 3m USB cable for a 1.5m USB that I have on loan. Same manufacturer, but 'higher-up' in their range. The USB is the link between my server and my speakers which have built in DACs and AMPS.  I wasn't expecting any noticeable change but I was wrong; the change was very noticeable:

 

 - first: it was a immediately obvious that the output volume on my speakers increased. So I checked this by swapping cables and measuring dbA levels on a sine-sweep test track that I use to calibrate levels. I was right and there was just under a 2dB vol increase when using the shorter, 'higher grade' cable over the longer 'lower grade' cable. I checked this 4x by swapping between the cables and had to adjust the pre-set on my speakers for the loaner cable.?

 

- second: there was a tangible/significant improvement in the sound by using the the shorter, 'higher grade' cable by whatever subjective assessment that I used. It was readily and easily discernible. 

What I don't get is *how* the playback volume can increase when all I am doing is shifting 1's and 0's over a 5v/3.6v cable and secondly, if the improvement in sound quality is say attributable to better rejection of EMI/RFI from my source to the DAC, or control of jitter, can it *really* be so significant over a length of 1.5m?

 

As Fokus is alluding to, the nature of a digital signal is such that it is very difficult (as in really really difficult) to even conceive of how a change at the physical layer caused by the cable length, or build materials, or design, or fill_in_the_blank Audiophile speculation/belief/myth could lead to an alteration of the signal in just such a way that would lead to all the bits being modified in just such a way to a perfect multiplication of the bits to lead to a perfect db increase (with not apparent side effects).

 

davide256 recommendation to "think like" (in this case, comparing digital communication to "contrast") is at the root of so many of the rabit holes in Audiophiledom.

 

As to your experience, the most likely explanation is your missing something unobvious but nevertheless not related to the cables at all except maybe ancilar way, like how you bump the volume control when you change cables ?

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14 minutes ago, Archimago said:

Mazza,

If this is true that an AQ Diamond is able to cause a 2dB volume difference over the USB digital interface (I assume this is to your Kii THREE system), doesn't this speak poorly of the Kii's digital design?

 

If this is true, does the company then warn people in the manual that the USB cable can make quite a significant impact on the sound because for whatever reason it's remarkably sensitive to timing or noise!? Maybe list a few "optimal" cables to purchase? Perhaps they should then have included a USB cable with the package to ensure that end-users are not ending up with inferior sound. Who knows, if this is true, then different cables might have even more effect - +/-3dB? +/-6dB with 15' cables anyone?

 

Kinda sucks to purchase a Kii system if this is true. [Which I highly doubt.]

 

4 minutes ago, Mazza said:

 

Yes, but it's puzzling as to what it could be, certainly it is not bumping the volume control, because I am measuring the volume of the sound using a Behringer mic. My ref isn't just some notches on a volume dial.

 

The usual physical layer explanations (i.e "timing", "noise", etc.) in no way account how a digital communication signal such as USB could be effected in just such a way to lead to an exact 2db increase.

 

I have not explanation of your UFO experience Mazza.  The most likely is that you are an astroturfer here to give yet another Audiophile cable tent testimonial.  In other words, you are lying.  OR perhaps your an oddball who likes throwing the forums into a frenzy.  OR perhaps you are experiencing something and wrongly focusing on the cable change (missing the real cause entirely).  

 

Perhaps someone with USB physical layer experience will come along and explain how some endpoints are designed with a built in volume adjustment (which would be a DSP/digital layer adjustment) depending on some signal variation that could be the result of cable length (the OP is mentioning a 3M to 1.5 M reduction) or some other factor such as using weirdly specd "audiophile" USB cables from AudioQuest or any other such manufacturer...

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5 minutes ago, Mazza said:

 

I have to say the Kii's are stunning and I have nothing but praise for them....everything I do to my system just seems to bring out more and more musicality and resolution out of them.

 

Well, there is your explanation.  In the audiophile art of system tweaking, everything leads to more "musicality", more "resolution", more (where is Ralf Arnott when you need him).

 

What are you selling?

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1 minute ago, Mazza said:

 

Thanks for the supportive words.

 

I am not trying to push any cable agenda, in fact if you go back to my OP I deliberately didn't mention cable or equipment so to avoid any fanboy accusations. There is merely a phenomena which I don't understand which I put to the forum to ask if anyone knows better.

 

I can hardly imagine the forums are going to get into a frenzy over this small matter!!!!!

 

But thank for your contribution

 

Your welcome, but I and many others (certainly those who lean to the real and "objective") are not here to "support" you.  It is not about therapy, but the truth.  In the end, if folks are to be helped the truth must be involved.  I don't see the truth in your experience or in your post.  I could be wrong, and will admit it if I am, but I suspect this cable testimonial thread will end up just like the rest of them...

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3 minutes ago, Mazza said:

 

Here we go, the insults start. I am not selling anything, I merely asked if anyone knows why I got an odd result

 

If it walks like a duck, smells like a duck, and poops like a duck, it probably is a duck.  Of course, you already knew this.  

 

If you experience is real and has a realistic explanation that is really related to USB/digital communication (the 1's and 0's of your titillating subject line), then I will offer a mea culpa, not for insulting you (which is a red herring on your part) but for doubting your experience.  

 

Until then, it's a UFO sighting...

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1 minute ago, mansr said:

I can think of one vaguely plausible explanation along those lines. Suppose the long cable is so poor that it drops down to USB 1.1 full speed while the short one manages to support USB 2.0 high speed. As a result, different OS drivers might get used, or the DAC might be otherwise differently identified. This in turn could lead to different saved volume settings being applied. A lot of ifs and mights, but it's not entirely impossible.

 

Yes, the OS (of either end) switching drivers...The OP mentions a "server" - does he have (if user configurable) a "bit perfect" (turning off all OS DSP processing) on said server, and is it really ever truly defeatable...but like you say possible but many ifs

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1 hour ago, Ralf11 said:

are you measuring the volume with a volt meter at the speaker terminals?

 

 

His speakers have amps and DAC built-in so there are no speaker terminals that he can use.  So the USB cable is going directly into one speaker, and then perhaps a proprietary connection from one speaker to the other.... Firedog probably clear this up.

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2 hours ago, Hugo9000 said:

What's in this thing?  USB has power, so perhaps this is an active device, and not that battery-attached-to-a-shield-or-whatever thing AQ does on their analog interconnects and speaker cables.  Apple and Google pack a DAC and HP amp into the end of a tiny USB-C headphone adapter.  This thing is enormous by comparison.

 

 

Is this the USB cable (that is obviously more than a cable) the OP is using?

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1 minute ago, Mazza said:

 

Looks like it could be, there are two in the range that have this. 

 

Does the one your using have this?

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6 minutes ago, Hugo9000 said:

I think they say that it's the same, but we only have their word for it (and haven't they been caught using a few "tricks" in their demos over the years? lol).  USB cables have power, so it could be more than what's on their analog cables.  As far as I know, there are no tear-downs of this device on their USB cables.  I'm not curious enough to buy one to open it up, just as I never bothered with any of the MIT cables that had little boxes, either.

 

Just now, Mazza said:

To clarify... my original AQ cable (cinnamon) does not have this, the new AQ cable (Diamond) does.   They fit it to a number of their various cable range inc analogue cables. It is some form of dialelectric bias system. Don’t claim to understand how it works. 

 

 

Well, unless it has DAC/DSP capability built in (not entirely out of the realm of possibility in audiophiledom cable world), I don't see how it could be the cause of your experience directly.  I suppose coming back to mansr speculation, it could be somehow causing the endpoints to do funky USB speed/driver changes but this explanation is long shot as it is...

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30 minutes ago, gmgraves said:

There is no harmonic structure or any dynamics. The USB cable is passing DATA. The USB cable has no way of knowing what the data represents; it could be e-mail messages, video, 3-D rendering, anything!

 

It's probably this: