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
Jimmy/Rower, can either of you explain to me why the fairly unique minimalist designed DNM Reson analog stereo phono plug ICs that I use and like in so many ways sound as clean coherent and lively as they do? They essentially look like old style 300 ohm antenna wires but use a small gauge single strand wire. The simplicity of the design attracted me initially and I have been very impressed ever since.

Do think this is a sound design approach?

Thanks.
Jneutron, oops, did not mean to blow off your question, I have been assembling a new headphone system. For insurance I had the ICs and power cords broken in on the latest AudioDharma Cable Cooker and also sent them off to the cryo lab, figuring better safe than sorry. :-). I'm using small 1" tempered steel springs and heavy masses for isolation of modded Oppo 103 and hybrid tube headphone amp.
Rower,
You said:

You seem to be a little too easy to get upset about some things so it's going to be hard to please you. I'll do my best.

My response:

Nothing could be further from the truth. Your statement is a diversionary tactic being used in an attempt to push blame on others rather than admit to your own arrogance. It is a common enough tactic, many people use it.

You said:

Zero capacitance? Sure, my perfect conductor example was just that.

My response:

NO, you stated that when the insulation is a vacuum, there is no capacitance.

Here, I'll refresh your memory...you said this exact thing on 3/15/2013:

4.0 The dielectric would be a vacuum so we have ZERO capacitance and velocity would be 100%.

My response to that was No, a vacuum dielectric does not have zero capacitance.

In addition, I provided the free space permittivity number, 8.854 times 10 to the MINUS 12 farads/meter.

You then stated :

That number is much higher than I would have expected, too.

My response...

Your kidding, right? I provide a physical constant, free space permittivity, and you say it's higher than you expected??? This physical constant is taught to ALL physicists and engineers, as well as in every AP physics course in high school I've become familiar with. It is needed to calculate capacitance. You've never seen it before, have you.

It is also "odd" that someone would thing that the number .000000000008854 is "larger than expected"..

This statement of yours is a very clear indication:

3.0 Carries energy in BOTH directions at the exact same time. Umm...this is a short circuit in reality.

My response:

WHAT???? A SHORT CIRCUIT????

YOU ARE ABSOLUTELY CLUELESS WHEN IT COMES TO TRANSMISSION LINE THEORY, FREE SPACE WAVE PROPAGATION, AND EVEN SIGNALS TRAVELLING THROUGH INDIVIDUAL CONDUCTORS.

Pay attention.

There are many websites out there which explain transmission lines and signal propagation. Find them and learn from them.

You stated:

I can't say I grasp speaker cable impedance at such low frequencies as they "rise" as the frequency drops, making consistent low impedances at audio seem implausible, at least to my way of thinking about the measurements. My guess is if you look at the cable like a T-line, the impedance is the same at any cable length. Of course, the low pass nature of the cable changes too.

My response:

I CAN say I grasp cable impedance. I can say I understand real skin effect. I can say I understand transmission line theory. The reason:

I am an EE. I do this for a living. I've done so for 35 years now. And I do it at a level which unfortunately, makes my resume incomprehensible to almost all EE's at the ScB level, most at the masters.

I am more than happy to share my understandings on the web so that others may learn.

I am not so happy when wannabe "engineers" attempt to use arrogance, belittlement, hobbyist website content, and rambling incoherent prose disguised as "technical speak" to badger others. Your type of "engineering" is one of the primary reasons cables and cable discussions are stuck in a quagmire.

I have provided valid reasons why cables can sound different, speakers, IC's, as well as power cords. Not that they all do, but rather, the physics processes which do impact the electrical function at some level.

That stated, if you wish to discuss actual technical things and how they can alter sound, fine. I've no problem with that. But you have to drop the shtick, it's old, it's worn, and you can't support the technical arguments.

jn
Mapman,

Yah, they do look like the old style antenna wires...

That configuration will increase inductance and lower capacitance. Low C is always liked by the audio guys.

This also increases the characteristic impedance of the cables as well. Phono ins are 45K give or take, amp ins run 10k give or take. That style certainly is closer to the load impedance than normal coax (50-75) or twisted pairs (100-150).

There are a few ways to skin the cat so to speak.

Shielding as per coax protects the higher impedance inputs from stray E fields, that cable doesn't.

Twisted pairs is not as good for E field, but is better for magfield protection.

Parallel such as that is worst case for both in terms of shielding.

You've traded off noise and hum protection to gain in capacitance and impedance.

But honestly, if you have no noise or hum issues, that is great..Tain't broken, don't fix it.

All IC's can suffer loop induced hum and noise incursion from external magfields, but you seem very happy.

Is it a sound design approach? Yes, it certainly is. If you had noise or hum issues, it would not be the best design approach for your system.

ps. AS a general rule, if a circuit is lower than 377 ohms impedance, it is sensitive to inductance and time varying magnetic fields. If the circuit is over 377 ohms, it is more sensitive to capacitance and time varying electric fields.

It is also important to consider the level of the signals in the circuits as well. Speaker runs will be inductance sensitive to a point, but external magnetic fields can't really compete with 100 or 1000 watts of power.

jn
Geoff,

You mentioned tempered springs. Do you get involved in the tempering at all? I ask because antique clock mainsprings tend to lose their strength over time, and I suspect that I may be able to re-temper them after opening them up again, perhaps oil or maybe water quench. I was wondering if you've had any experience in that.

And, you did indeed blow off the question again. I wasn't asking about your work....I was asking about you.

John