Auditory Dementia

There was a discussion on this forum a few moons ago where another contributor effectively claimed I was deluded in thinking I could remember the sound of a recording for more than 4 seconds, quoting this same science.

Let's face it, scientists are always having to modify theories because most of them are based 50% on measurable fact and 50% on what they think or believe. The speed of light in a vacuum is constant... oh, hold on, perhaps it isn't after all...

At this point I'd like to veer off-topic for a while and look into cable direction...

And I do this at the risk of the "extremists" getting highly aggitated.

There is also a Rational Wiki page about Audio Woo, which reads as if it's someone's personal opinions, and I'm sure this will upset him too.

However, when studying maths (at Durham, by the way), we discussed domains, and how mathematical arguments may, or may not exist outside a particular domain.

I state this before introducing a subject known as HVDC - high voltage DC power transmission, because the know-all's will immediately dismiss it in their haughty way, as being in a totally different domain. Remember, I stated that we'd discussed how mathematical arguments may, or may not exist outside a particular domain - which shows a possibility of what I could crudely call "what's good for the goose is good for the gander".

Taking a look at page 19 here: http://www.pesicc.org/iccwebsite/subcommittees/subcom_c/Presentations/2009Spring/C-4-HVDCTransmissionCableSystems-Zaccone.pdf

The following can be read: "In fact, an Extruded Insulation (generally PE based) can be subjected to an uneven distribution of the charges, that can migrate inside the insulation due to the effect of the electrical field. It is therefore possible to have an accumulation of charges in localised areas inside the insulation (space charges) that, in particular during rapid polarity reversals, can give rise to localised high stress and bring to accelerated ageing of the insulation."

The Rational Wiki article simply says: "Some audiophiles believe that a cable will perform differently depending on which way it goes (e.g. which way the electrons move along the cable). Naturally, this is completely bogus, because cables are not made of diodes."

As an engineer with 40 years under my belt, I am not thick! I know that cables are "not made of diodes"!!! Most customers also know that - they are not thick either!

Returning to the HVDC piece we can see that there are other factors such as "space charges", which is nothing to do with the metal of the wire or its capacitive coupling to the return wire, or shield, depending on what cable we are referring to, or its inductive properties.

Now, I'm sure the next criticism would be that HVDC, even if this worked at lower voltages, is DC and not AC, but HVDC is AC converted to DC without smoothing (which would need lots of farads of high voltage capacitor - good luck!). Therefore it has a waveform, and it's also low frequency, which might be 50/60Hz, and those frequencies are audible frequencies.

But before I'm accused (as I have been), I will say I have never said categorically that cable directionality exists, simply because I have no proof!!! Can they get that through their thick skins?

I can only observe, and this is what I have observed...

The cable we buy has been insulation tested. This is similar in some respects to what is called "flash testing" (a thing we do on PSU1 power supplies as required by our CB safety certification). Insulation testing is an electrical strength test, where it is subject to a high voltage and often that voltage is DC, because if it were AC, it would require more power. Therefore the cable has been "used" at HVDC!

Every new reel of coax has a test pair of terminated interconnects made from the first few feet of cable from the reel.

I am then given it to find out if I can honestly tell any difference by reversing the cable.

On some ocassions it is a quick and easy task to identify a direction that "arranges the tempo's of a set piece in equal time order", and one that doesn't.

Here it may take more than 10 seconds to reverse the cables (so really I suppose we're not far off-topic).

On some occasions it is very hard to tell any difference at all.

Once that test is done, the cables are marked to show the direction of what in my opinion is the better of the two, based on the direction of that sample.

It has been noted that with an "aged" cable that there is no noticeable difference as to direction - in my opinion - and from the (good) feedback we get, customers tell us that the directionality has "faded".

I suppose it could still be argued that we're all making this up?

But going back to the "space charges" (the accumulation of charges in localised areas inside the insulation) due to HVDC, and the fact that the new cable was subjected to HVDC (the "hipot" test), then it could be argued that these accumulations of charges affect the rapid polarity reversals that an AC audio signal actually is?

Maybe it could - maybe not? I am not forcing this on anybody!!!

And as the cable directionality seems to fade with time, then these accumulations of charges in localised areas inside the insulation (due to HVDC???), could be dissipating?

Having dissipated, the cable no longer has any directionality.

Then, at that point, cable directionality ceases to exist, and because of that, it would be illegal to sell a cable as having directionality - AND SO WE DON'T!!!

But then it raises a possible proof for something else....

Cable Burn-In!

So perhaps it is time now to head for the hills, before the "extremists" get us with their torches and pitchforks?

The thing is, it's a thin line between science and woo/foo, and the sooner people start understanding real woo/foo from what has an element of truth, the better it will be for all!