2. cables
  3. 1363313104

Why are we going 300 or more directions?

Funny, if you design a hi-speed coaxial cable, the fundamental design is the same. I do mean the same. Physics have honed the basic construct to the same physical design no matter who makes it.

Yes, conductor and shield materials will change some based on the frequency range, but not the design. If you change the basic design, you get worse performance, and not just differentiation (unless worse is your differentiation).

Then we have audio cables. True, audio exist in a frequency range where stuff does change with respect to frequency (impedance drops markedly as frequency is swept from 20 to 20 kHz) but this still doesn't allow willy-nilly designs from A to Z to hold the best electrical ideal.

If there are X number of speaker cable makers, only a small few can be the most ideally right according to physics for audio transmission. What we have is so much differentiation that it is almost humorous.

If "we", as in speaker cable designers, all got in a big room with the door locked and could not be let out till we balanced the design to best effect...what would that cable look like? Why?

Go to any web site and you can't get one-third of the way through before vendors allow misconception to be believed (references to velocity of propagation for instance) that are meaningless in their feint of hand or simply unprovable as to their effect...simply fear you don't have it. For instance, high velocity of propagation allows you to simply lower capacitance, the speed is there, but irrelevant at audio and cable lengths that you use. The signal travels too fast to matter. Signal delay is in the 16ns range in ten feet. Yes, that's 16 trillionths of a second. It's the capacitance folks, not the velocity that you engineer to. But velocity "sounds" exciting.

Audio cable over the years should be under CONSOLIDATION of principals and getting MORE like one another, not less so. I don't see a glimmer of this at all.

The laws of physics say there is a most correct way to move a electrical signal, like it or not. Electrical and magnetic fields have no marketing departments, they just want to move from A to B with as little energy lost as possible. You have to reach a best balance of variables. Yes, audio is a balance as it is in an electromagnetic transition region I mentioned earlier, but it STILL adheres to fundamental principals that can be weighed in importance and designed around.

A good cable does not need "trust me" engineering. An no, the same R, L and C in two cables don't make them the same. We all know it isn't that simple. BUT, the attributes (skin effect and phase responses) that DO make those same R, L and C cables different aren't magic, either.

I've listened to MANY cables this past six months, and it no longer amazes me which ones sound the best. I look at the several tenets that shape the sound and the designs that do this the most faithfully always come out on top.

DESIGN is first. Management of R, L, C, Skin effect and phase. Anyone cam stuff expensive material in a cable, few can DESIGN the right electrical relationships inside the cable. Why be stuck with excessive capacitance (over 50 pF/foot) to get low inductance (less than 0.100 uH/foot) when it's NOT required, for instance. A good design can give you BOTH!

MATERIALS are a distant second to sound quality. They contribute maybe 2 tenths of the total sonic equation in a quality design and ZERO in a bad design. A good design with standard tough pitch copper will exceed a bad design with single crystal cryogenic OFC silver-plated copper. You can't fake good cable design and the physics say so. Anyone can buy materials, so few can do design.

Being different to be different isn't a positive attribute in audio cables. Except for all but ONE ideal design it’s just a mistake.

I've listened to the same cables with dynamic speakers and electrostatic speakers, and the SAME cables always come through with the same characteristics. Good stays good. True, the magnitude of character is different, but the order hasn't moved.

I'm not real proud of the cable industry in general. True transmission accomplishments should reach common ground on explainable principals and that SHOULD drive DESIGN to a better ideal. But, we people do have emotions and marketing.

What do I look for in a speaker cable?

1.0 Low capacitance. Less than 50 Pf / foot to avoid amplifier issues and phase response from first order filter effects where the phase is changing well before the high-end is attenuated. The voltage rise time issue isn't the main reason low capacitance is nice, it's that low capacitance removes the phase shift to inaudible frequencies and doesn't kill amplifiers.

2.0 Low inductance as we are moving lots of CURRENT to speakers. Less than 0.1UH /foot is what you want to see. Good designs can do low cap and low inductance, both.

3.0 Low resistance to avoid the speaker cables influencing the speakers response. The cable becomes part of the crossover network if the resistance is too high. For ten-foot runs, look for 14 AWG to maybe 10 AWG. Bigger isn't better as it makes skin depth management issue too hard to well, manage.

4.0 Audio has a skin depth of 18-mils. This is where the current in the wire center is 37% of that on the surface. The current gradients can be vastly improved with smaller wire (current closer to the same everywhere). How small? My general rule is about a 24 AWG wire as this drop the current gradient differential across the audio spectrum to a value much less than 37%. Yes, that's several wires. Don't go overboard, though. Too much wire is a capacitance nightmare. Get the resistance job done then STOP at that wire count.

5.0 Conductor management. Yes, point four above says more than one wire, many more! And, if you use 24 AWG wire for skin depth management, it can be SOLID to avoid long term oxidation issues. I've taken apart some old wires and it can look pretty bad inside! Each wire needs it's own insulation.

6.0 Symmetrical design. Both legs are identical in physical designs allows much easier management of electricals.

7.0 Proper B and E field management is indirectly taken care of by inductance and capacitance values. The physics say you did it, or you didn't. BUT, you can design in passive RF cancellation if you use a good design, too. Low inductance says that emissions will be low, however, as less of the energy is generating an electric and magnetic field around the wire, thus limiting EMI / RFI emissions.

8.0 Copper quality is finally on the list. It doesn't matter without one to seven! The smaller the wires (infinitely small), the LESS the silver plate will warp the sonics. If the current density is the SAME at all frequencies, then all frequencies see the same benefit. If a wire is infinitely big than the high frequencies will see the majority of the benefit. 20 Hz and 20kHz are at the same current density on the wire surface. But, the gradient difference is too small to matter with 24 AWG wires. If you want silver, let the silver benefit everywhere!

9.0 Dielectrics. Dead last. Why? Because capacitance is driven by your dielectric. If you have the low cap, you have the right dielectric for the design. You HEAR the capacitance and NOT the dielectric per say. True, Teflon allows a lower capacitance for the same distance between wires, thus making lower capacitance. But, if you FOAM HDPE from 2.25 down to 2.1 dielectric constant, it can meet the same cap at the same wall and sound just as good. Careful though, it is now more fragile! It's a trade-off in durability, not sound quality. Teflon isn’t magic. It is expensive.

10.0 This is not last per say as it is CHOICE in design. I do not like fragile cables laying on the floor to be stepped on. Some do. A good cable design should be durable enough to take that late night trip to the TV set with the light low, and then step on your cable by accident. The cable should be user friendly.

Everything above can be calculated by known physics equations with the exception of copper quality on sound. I'll have to hear this on two IDENTICAL cables except wire quality. But, why would a vendor allow you to do that when they can scare you into a more expensive copper? I'll be glad to pony-up if I'm allowed to make the judgement for myself. Or, let be buy it at a reasonable price!
rower30
charles1dad's avatar
charles1dad
10,230 posts
 
Audiolabyrinth,
It appears to me Rower30 is actually making the case for the
importance of high quality cable. His point that excellent design and high cost aren't linearly related is logical and true in many cases.
Regards,
rower30 OP
211 posts
 
Audiolabyrinth

Cables are indeed science and DO INDEED make a cable sound in specific ways. The electromagnetic spectrum could care less about price, that's a given. Price is a human emotional endeavor based on marketing and the wants of the consumer. So I don't care about price. The raw material cost of even the most expensive cables is maybe a few hundred dollars. You pay for what they sound like relative to one another, regardless of the material costs. You WANT the SOUND, not the price. The price you pay to GET the sound. Well, most of us do this. A few sure do buy based on a price and stick it in a corner like a statue never to be heard from again.

Now to the DESIGN. Sorry, but there is but ONE best way to move data in a given electromagnetic situation. Anything outside of that is simply less capable and not as linear. Keeping cables as honest as you can based on well-known principals is important.

"My" science (I never was thinking I had science so much as the world we live in has physical science) is as defined as it can get for R, L, C and skin depth. It's all 100% repeatable by anyone. Following specific design guidelines will indeed make a better cable. Most market their differentiation, not good design. Physics can't be differentiated, only misunderstood and used incorrectly.

What isn't as repeatable is the exact interaction of variables as a whole as, like I said before, we have a very nonlinear electromagnetic spectrum audio is stuck in. So the balance of all variables inside the preferred "box" of measured values will shift some depending on what speaker and amplifier you use. But, a well-designed cable has ALWAYS sounded better with any amp or speaker combination I've ever used, or compared cables on. Try C4's with W-8's and then Martin Logan Summits with McCormack amps. Can't go much more different than that. Good cables stayed good. The changes in fundamental transmission characteristics aren't so large as to require a completely different cable design.

I don't listen to cables? From my post, I'd guess all I do is listen to cable, but anyway...I have $5,000.00 NORDOST cables in my system and listened, and still am listening, to speaker cable up and down the price line. If time is somehow important in all this, I've been at it longer than you, I'm 55.

I paid thousands for the Tyr2 NORDOST XLR pre to power interconnects based on their sound (I listened to many other XLR's). They have a superior overall design that puts their overall fingerprint well inside the box of electromagnetic reason (for XLR cables). I do not find their superior overall sound to be surprising as the measurements driven by the design allows them to sound good. There are other vendors that follow strict design guidelines that allow superior performance, but way too many sell FUD and innuendo and / or jump to RF communications principals at audio frequency ranges in which nearly all the variables of influence CHANGE! So WHY ON EARTH go to RF calculation in audio cables?

I'm somewhat confused by your demand that I include price into this. No, I include DESIGN. That's it. You can ONLY buy and understand the physics of a DESIGN. The price is irrelevant to the sound. The more you understand how cables work, the less you need to pay for differentiation that is nothing more than that. Usually, the differentiates tears apart the ability of a cable to follow best in practice designs, and you pay MORE for that privilege?
geoffkait's avatar
geoffkait
23,365 posts
 
Oops, somebody forgot wire directionality. I forget in which electronics textbook that is discussed. :-)
rower30 OP
211 posts
 
No, didn't forget directionality it at all, it doesn't matter. Audio signals are not truly symmetrical or balanced (plus to minus signal don't subtract to zero) as impulse noises are more positive amplitude than the negative decay. Look at a piano or drum strike, for instance. Yep, more stuff on the positive side than the negative side. But this is no reason to think the "positive side" needs help.

The waveform is alternating current and travels BOTH directions with respect to polarity. What half of the waveform do you want to be biased with the copper "grain" structure? If this was a DC signal, rubbing against the copper grain structure the wrong way may be a fun FUD argument. But since audio cables aren't a cat and get pissed when rubbed the wrong way and are AC in nature, this concept of current "direction" when it has reversal changes to even play music is rather odd.

I already discussed polarity reversal timing (fast as the dickens) in the dielectric relative to single directional changes. How on earth could AC signals even be transmitted if the dielectric were "slow"? Coaxial cables transmit in the 6 Gig frequency range all day with out directionality just fine, thank you. And, their dielectrics don't need help...

DC dielectric bias systems are also perplexing. DC bias systems further tell you that the signal could care less about directionality and polarity as a DC bias system theoretically makes it HARDER to polarize in the opposite direction of the bias. All good dielectrics polarize so fast that a DC impediment doesn't audibly affect the sound, just your pocket book. Why so much concern for the BIAS in the ONE direction only? And no, a dielectric doesn't take seconds, minutes, hours or days to polarize. It takes 10 to the minus fourteen seconds. Do they wander around after power is removed? Yes. Do they snap back into control IMMEDIATELY when a signal is applied? Yes. If you listen to music at the 10 to the tenth power in frequency...be worried, very worried, as the polarization can now not keep up. So how does a DC battery bias system add speed to an audio signal dielectric and to both polarities, not just one?

But if you must, mark your cable and add an arrow to make you feel good along with a battery and heavens don’t put the battery in the wrong direction! :)

I'm not against REAL design metrics that is repeatable and you can design around. To jump to RF wave-guide signals and force an issue at audio is simply misguided. Audio cables are hard enough without using physics the wrong way.

All the attributes I discussed are measurable at audio, and the improvements to them rational in a good design. Diectionality, DC bias and many others are not. But if you want to add nonesense to cables, why not add it to a cable that at least is designed right up to the arrows and battery installation steps? Are we tossing out what we can measure and replacing it with what we can't? Yep, we see pages of FUD "data" (differentiation)with no mention of the compliance to the physical basics. If a cable meets the basics, at least the FUD stuff didn't hurt the sound, just your pocket book.
gregm
3,395 posts
 
Rower30: your original post & further "articles" are very interesting and, if i may say so, a significant contribution to the community.
I do of course agree with your basic premise but never have managed to put the matter in the same clear terms:)

Not surprisingly and for just as unsurprising identical reasons, the branded cables I use (I also use diy) are the same...
(And yes, the nuisance of "avoiding" that annoying HF phase shift makes me wish I had specialised in low voltage applications in my youth...)

A while ago I was trying to find the "optimal" gauge for a simple IC consisting of two conductors running parallel at ~1.5" apart, 2ft length, unshielded, using single strands of copper wire of course.
Not having the right equip to measure, I had to use my system & concluded that 24awg offered the best frequency extension, but lower gauges more "dynamics" (i.e. 24 is over the R turning point it seems). As I use a transformer volume control, the above is not necessarily optimal on "normal" systems...

What recipe do you use for the speakers -- if you wish to describe it of course. I understand if you don't; the matter interests me as the mid-upper frequencies amp I use is wide bandwidth and I have to be careful....
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