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Belden on interconnect cable design

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Belden on interconnect cable design

Postby Martin Walker » Sun Oct 13, 2019 1:30 pm

Just discovered this fascinating PDF from famous cable manufacturers Belden, which seems to employ REAL physics rather than snake oil. See what you think! ;)

https://www.iconoclastcable.com/story/rcaxlr.pdf


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Re: Belden on interconnect cable design

Postby Hugh Robjohns » Sun Oct 13, 2019 2:21 pm

Good find Martin, that looks like an interesting read. I'm looking forward to it.
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Re: Belden on interconnect cable design

Postby n o i s e f l e ur » Sun Nov 03, 2019 11:59 pm

Martin Walker wrote:Just discovered this fascinating PDF from famous cable manufacturers Belden, which seems to employ REAL physics rather than snake oil. See what you think! ;)

https://www.iconoclastcable.com/story/rcaxlr.pdf


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I'm not an EE, nor do I play one on TV . . . but is there really such a thing as group-delay in an electrical signal? Seems to imply bass frequencies arrive later due to differences in crystalline structure of the copper wire! Or have I completely misunderstood what he means by group-delay?

Physics AS snake-oil?
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Re: Belden on interconnect cable design

Postby James Perrett » Mon Nov 04, 2019 2:12 am

Yes, group delay exists but is unlikely to vary with frequency at audio frequencies (unless you have an unusually high capacitance or high inductance cable). It is the sort of thing that microwave engineers worry about.
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Re: Belden on interconnect cable design

Postby Hugh Robjohns » Mon Nov 04, 2019 9:57 am

Yes it certainly is a very real physical property, but it's an insignificantly small variation in most conventional cables at audio frequencies.
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Re: Belden on interconnect cable design

Postby Folderol » Mon Nov 04, 2019 10:26 am

I dimly remember it coming under discussion when TVs moved form VHF the UHF, but hadn't heard anything regarding audio, so I guess it would only be a potential issue if you were doing some highly complex manipulation over long cables.
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Re: Belden on interconnect cable design

Postby n o i s e f l e ur » Mon Nov 04, 2019 1:29 pm

Yeah, a perusal of the Wikipedia page on the phenomenon set me straight on the matter - I'd previously only been aware of group-delay WRT loudspeaker / acoustics, which made sense.

I think the mere mention of microscopic grain structure of copper in the paper set off my spidey-sense that yet another cable manufacturer was abusing science in an effort to justify why their magic wires improved audio quality - the very definition of snake-oil.

To be fair, they (Belden) don't look like they're in the same space as say . . . Monster Cable, and they look to be well engineered and constructed products - which is bang on the advice I've always seen profferred in this parish.

@ Folderol - dunno about manipulation, but it would appear Belden certainly do play in the space where long cable runs are common.
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Re: Belden on interconnect cable design

Postby Hugh Robjohns » Mon Nov 04, 2019 2:16 pm

n o i s e f l e ur wrote:I'd previously only been aware of group-delay WRT loudspeaker / acoustics, which made sense.

It occurs anywhere that filtering is involved (intentionally or otherwise). It's the engineering way of describing the different phase shift amounts that occur at different frequencies as the signals pass through filter networks (which a cable inherently is, too!).

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Re: Belden on interconnect cable design

Postby James Perrett » Mon Nov 04, 2019 2:53 pm

n o i s e f l e ur wrote:To be fair, they (Belden) don't look like they're in the same space as say . . . Monster Cable, and they look to be well engineered and constructed products - which is bang on the advice I've always seen profferred in this parish.

They're usually pretty sensible so I'm a little surprised that they are trying to edge into audiophile territory. I think Steve Lampen is still their studio contact and he has a blog page at

https://www.belden.com/blog/broadcast/a ... eve-lampen
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Re: Belden on interconnect cable design

Postby n o i s e f l e ur » Tue Nov 05, 2019 1:04 am

James Perrett wrote:
They're usually pretty sensible so I'm a little surprised that they are trying to edge into audiophile territory. I think Steve Lampen is still their studio contact and he has a blog page at

https://www.belden.com/blog/broadcast/a ... eve-lampen

Actually James, on re-reading the opening salvo in the PDF Martin linked, I don't think they are. They link to a phys.org paper, and quote from same . . . but it's a complete red herring, as the author immediately states its irrelevance lol! Which, in my haste and ire, I completely missed on first read.

I don't think (fundamental) physics plays a great role in the article, it's basically a tract on engineering by the looks of it.

Hugh Robjohns wrote:
n o i s e f l e ur wrote:I'd previously only been aware of group-delay WRT loudspeaker / acoustics, which made sense.

It occurs anywhere that filtering is involved (intentionally or otherwise). It's the engineering way of describing the different phase shift amounts that occur at different frequencies as the signals pass through filter networks (which a cable inherently is, too!).

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Indeed! I gathered as much from the Wikipedia article Hugh. ;) I guess any transmission medium short of superconduction could be regarded as a filter . . . and even then the problem just shifts to interfacing with the brain. So - SQUIDs? :D

Apologies to all. Itchy trigger-finger on the audiophile nonsense, brought on by a recent visit with an acquaintance who has north of 30K worth of hi-fi including a set of Wilson Audio speakers . . . through which he listens mostly to mp3s, webstreams and vinyl.
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Re: Belden on interconnect cable design

Postby Hugh Robjohns » Tue Nov 05, 2019 10:51 am

... in an acoustically untreated room, no doubt! :crazy:
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Re: Belden on interconnect cable design

Postby jaminem » Tue Nov 05, 2019 11:24 am

Got a few paragraphs in before my mind imploded...

However, since snake oil was mentioned - has there been any research around how your brain can trick you into believing you can hear a difference between 2 sources even if there isn't any?
You know people swear blind they can hear a difference in audio quality following the purchase of a wooden mains plug, or an 'audiophile' Ethernet cable, has anyone managed to prove/disprove this?
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Re: Belden on interconnect cable design

Postby n o i s e f l e ur » Tue Nov 05, 2019 1:33 pm

Hugh Robjohns wrote:... in an acoustically untreated room, no doubt! :crazy:

Yep! To be fair, it was just a living room - not any sort of critical monitoring environment. I did suggest some treatment (acoustic!).


jaminem wrote:Got a few paragraphs in before my mind imploded...

However, since snake oil was mentioned - has there been any research around how your brain can trick you into believing you can hear a difference between 2 sources even if there isn't any?
You know people swear blind they can hear a difference in audio quality following the purchase of a wooden mains plug, or an 'audiophile' Ethernet cable, has anyone managed to prove/disprove this?


There's been absolutely tons of research, and what it reveals is that placebo is both very real and very effective - so those people who swear blind they can hear an improvement? Very likely DO perceive an improvement! Well, a certain percentage of them anyway, the rest are just lying / taking on a burden of cognitive dissonance.

And then there's voodoo - also real! (Nocebo) :D
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Re: Belden on interconnect cable design

Postby Hugh Robjohns » Tue Nov 05, 2019 2:16 pm

n o i s e f l e ur wrote:To be fair, it was just a living room - not any sort of critical monitoring environment.

Surely, if the chap is blowing £30k on hi-fi it is, by definition, a critical monitoring environment! :-)

I do appreciate the aesthetic problems of installing effective acoustic treatment in a domestic setting. I just don't get the sense of blowing that kind of money and then not being able to appreciate what it can (or can't) do!

I've told this story many times before, but it is relevant! I attended a product launch at the British Grove studios. Pro-audio company launching a consumer DAC, so wanted a pro setting to reinforce their credentials. Demonstration playback was from a laptop connected via USB to the converter placed on the (API) console meter bridge inthe main control room, and the audio was coming from the soffit-mounted ATC 300s in the front wall.

Needless to say, it all sounded stunningly good and the invited audience of mainly hi-fi journalists and reviewers were quick to say so... starting a debate about how the sources must be at least 24-bit 192k or SACD etc etc... to sound so good.

I struggled to suppress my laughter at their astonished expressions when they were told it had all come from ripped CDs at 16/44.1 :lol:

They then decided that the stunning quality must be because of the special professional-quality cables that were being used... Some became positively apoplectic when they were shown a motley pair of mismatched cables from the converter XLR outputs into a TT patch panel behind the desk, and then how the signal was routed across the PO316 patch panel in the wall with more mismatched patch cables to the speaker amp inputs!

The one thing none of them seemed to appreciate as being key to their enjoyment, was the superb reflection-free acoustics of the control room!

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Re: Belden on interconnect cable design

Postby n o i s e f l e ur » Tue Nov 05, 2019 2:52 pm

Oh, I agree wholeheartedly Hugh, and it's not like he couldn't afford some treatment either, having spent so much on the playback equipment.

The other crazy thing was, the room itself presented no problems vis a vis aesthetics as it was a very large room by domestic standards. Big old Georgian room, 7*5*3m at least . . . bags of space to get creative even if the nature of the room presented its own problems.

What you said about the motley old XLRs kinda speaks to Martin's OP too!

I should perhaps clarify that I'm in no way accusing Martin of audiofoolery - I know he doesn't fall into that category.

Actually Hugh, while you're still in the thread I was wondering if you'd ever encountered Wilson Audio loudspeakers? I had a fairly mixed reaction to them - obviously they were very impressive in that they sure could pump out the SPLs . . . visually striking (in that they were some of the ugliest damn things it's ever been my misfortune to see!) but - something not quite right about their presentation of the material.

I think it was these ones;

https://wilsonaudio.com/products/sasha/sasha-daw

Check out that port on the rear for instance.
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Re: Belden on interconnect cable design

Postby Hugh Robjohns » Tue Nov 05, 2019 3:28 pm

Those Sasha speakers remind me (visually) of Kef models from the 1970/80s!

I've not knowingly heard those particular Wilsons, but I have heard others on the rare occasions I venture into a hi-fi show (usually the one in Bristol). I never cease to be amazed at how poor some ludicrously expensive hi-fi brands can be -- I had a very disappointing experience with a £50k stereo system at a certain British manufacturer's in-house demo room in Wiltshire, for example...

On the upside, though, my 15 year-old Bryston SP1.7 surround sound controller started to misbehave recently. All the indications suggested a power supply problem. Returned to PMC (Bryston UK agent) and fixed for free under the twenty-year warranty. Now that's what I call service! :-D

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Re: Belden on interconnect cable design

Postby n o i s e f l e ur » Tue Nov 05, 2019 4:24 pm

Eheheh . . . very diplomatic Hugh.

So - naming no names*, you'll never guess what comprised the rest of the system? ;)



* I SAID NAMING NO NAMES WHAT!
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Re: Belden on interconnect cable design

Postby Martin Walker » Tue Nov 05, 2019 10:50 pm

n o i s e f l e ur wrote:There's been absolutely tons of research, and what it reveals is that placebo is both very real and very effective - so those people who swear blind they can hear an improvement? Very likely DO perceive an improvement!

In a documentary I watched about placebos used in medicine to test the true effects of new medication, even those subjects who experienced improvements in symptoms after being prescribed the placebo continued to gain these benefits when they carried on taking sugar pills :headbang:

The human brain is a mighty powerful thing!


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Re: Belden on interconnect cable design

Postby Wonks » Tue Nov 05, 2019 11:07 pm

Even when people are told they are taking placebos, they still feel/do better than when taking nothing.

So trust me when I say that buying a £2000 IEC mains lead from me will improve the sound of your audio.

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Re: Belden on interconnect cable design

Postby James Perrett » Tue Nov 05, 2019 11:32 pm

Hugh Robjohns wrote:-- I had a very disappointing experience with a £50k stereo system at a certain British manufacturer's in-house demo room in Wiltshire, for example...

On the upside, though, my 15 year-old Bryston SP1.7 surround sound controller started to misbehave recently. All the indications suggested a power supply problem. Returned to PMC (Bryston UK agent) and fixed for free under the twenty-year warranty. Now that's what I call service! :-D

I'll bet your Bryston only went wrong because it hadn't been in for its 10 year service ;)

(No, I didn't know about the need for regular servicing either until someone refused to buy an amp from a friend of mine because it didn't have any service history).
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