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
Jneutron

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.

Zero capacitance? Sure, my perfect conductor example was just that. You can't do anything in that cables example let alone the capacitance. Not sure why you got so excited about it. Yes, a dielectric constant of 1.0 is a give away to the fact that capacitance can't be zero in THIS world, but I wasn't limiting the perfection to the real world but the "perfect" world where things do go infinitely fast, have no resistance, ETC. I see no sense in making a "perfect" wire half-in one world and then the other. So, I put it all in ONE world.

And yes, you're right, I do not have a source for very low frequency skin effect. Nor does it seem anyone else! As long as the numbers are "close" and you use a wire size that is smaller than the calculation, and use the number of wire to meet DCR things should get into the reasonable range.

As far as transmission line effects well, the source impedance sure is small at less than 0.05-ohms on average of an amplifier's output stage. The cable impedance is small (looking at the real component of the cable) compared to the speaker's varying input impedance so it is hard to imagine the speaker cable as a classic transmission line (matched source, line and load impedance’s). Not to mention the wavelength are WAY long to even begin to couple between the source and the load. A reflection bridge certainly can show reflections but to say this is a transmission line?

If I shove my amplifier up to the speaker terminals where is all the power dissipation going? the speaker. If I stick a cable in there, the power is still going almost all into the speaker and not the cable. The L and C energy eventually goes into the load but is lagging one way or the other. Probably not a good thing.

True, the "impedance" of the cable can be complex in nature and a higher vector magnitude per low frequency equations (mostly capacitive, as the resistive load value is so small in the cable). But at such a low frequency it's really hard to see this as a transmission line, or impedance values near the speakers input impedance.

How do we negate the effects of the LONG wavelengths relative to the line length at audio? Even worse, go lower than 20KHz.

I'm all ears on your low frequency transmission line model (pun intended)and impedance matching. The Z=SQRT(L/C) is only good above 1 MHz.

The ability to design to metrics that are repeatable would be a great benefit to designers who want to use the best of what's really capable in design without "faith" based engineering. But, I'd rather try to do the right thing with a few bumps in the road than do the wrong thing perfectly. Too little risk can limit the outcome as bad as anything else. Yes, we lose a few that insist on only what they perceive and hear. That's fine, but for right now I want to concentrate on the "knowns" (yes, even the one's I don't know!) to look for in a nice, and reasonable, cable. Design elements that are always beneficial to sound.

Bridges go up and fall down, space shuttles go up and explode... all these things have "experts" at the wheel and still failed. People may be experts, but the ones that do their jobs can overreach even their understanding(s).

So, as far as being the second one, I sure didn't know I was competing with the first. Sorry about that. If I only stick with what I know today, what benefits do I achieve tomorrow?

Looking at cable, you can't see a common design thread across the lot of them that indicates forward thinking to a known set of conditions. I can even see a few, not hundreds, of designs for a specific set of amp (SS or VALVE)/speaker (dynamic or electrostatic) combinations.

I listen to cable with the same R, L and C and am amazed at how different they sound. I am not even close to shutting down my ears. That’s what got me in this mess! How do you recognize correctly made audio speaker cables.

I did look back at some of your post so as NOT to pester you, and yes, the main things my ears hear is much improved openness, imaging stability, precise location of the image and debth in good speaker cords.

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.

With your respone Jneutron, I close comments in this post. I've bugged you all enough.
Rower,

A simple followup.

Your first post to me included your words.."""information is power. get some.""

You are arrogant without foundation to be so.

I provided actual engineering on skin and cables, most taken directly from UNDERGRADUATE engineering E/M texts.

You "counter" with non peer reviewed content from audio hobbyist websites.

Your technical discussion attempts appear to be cut and pastes from online sources, mainly the same audio hobbyist websites, and how you meld them together tends to be both inconsistent and inaccurate, as though you do not have a real understanding of the topic..

Your attempt at diverting the discussion into one of ego has been seen before.

Like this gem...

Stated by rower::

But, I think some of this deservedly stuck to me with a little bouncing off me and sticking to you. True class keeps its class at all times. Yea, it's tough, I know. We do our best. Me, I'm fine with good information, being corrected and moving on. I don't use my knowledge to go hunting for those that don't without any real regards for the actual topic, just the hunt. Grow some civility with your posts and more will follow. You seem to be aware of this, so why not change it? Witness...

end of quote..

How old are you??? Bounce off me stick to you??? Stick to topic and please post more like an adult.
Enough of the unpleasantries, perhaps that chapter can be left behind? Your call.

1. Skin effect within a wire is NOT correctly calculated via the exponentional equation in the audio bandwidth. Skin effect is not as pronounced as the exponential equation describes. That is because the exponential equation assumes the energy is an E/M wave impinging on hte conductive material, NOT being generated by internal currents. You clearly have a problem understanding this. Do us all a favor, E-mail the owners of the sources you are quoting from , Rod Elliot the owner of sound.westhost, or Gene Delasalle, owner of Audioholics...give them verbatim everything I've stated on skin effect, ask them if I am correct. Both will either agree with what I've stated, or they will go to their trusted sources to ask what the story is. In which case, I might get some e-mails. I haven't been in contact with Rod in years, last time we discussed techniques for measuring doppler distortion in speakers, maybe 8 years ago... Gene, I discussed some article possibilities a few months ago.

2. Cables as t-lines at audio frequencies. Here, I guarantee both of your audio hobbyist website "sources" WILL have to contact higher level technical resources. There are only two sources on this planet I am aware of that understand this and have MEASURED, modelled, and quantified it cleanly. Cyril Bateman, and myself. (there may be more, I am not aware of them). Cyril wrote a really nice but unfortunatly extremely technical article which goes over the heads of most people. I am using this understanding to better a work project. Repeat, actual hardware.

I shudder at making this post so long, but the delays are incomprehensible to me...

Rower Quote/question:

I'd rather have half the knowledge and work towards a solution than all the knowledge and sit there with it. Jneutron, where are "our solutions" as you see them? What attributes do you look for?

End of quote.

Another slap upside the head. And you wonder why you have problems with someone of higher technical proficiency??

I stated that rather clearly before, go back and read. Human ITD discernment is 1.5 uSec interchannel max. Any effect which is in excess of that threshold cannot be discounted as inaudible. When the line/load mismatch is such that current group delay exceeds that threshold in the mid audio band where our undithered loclaization capability is strongest, method to reduce that delay are required.

Rower quote/question::

Jneutron, where should user's of Zobel networks calculate the impedance? What do you use when you suggest cable "impedance"?

End of quote..

I already stated that, you either missed it or did not understand it.

When a t-line is terminated by a load which matches the line, the amplifier DOES NOT SEE A CAPACITANCE. It sees a resistance. That is INDEPENDENT of the characteristic impedance of the cable. If you run a 5.77 ohm cable with 300 pf per foot and 10 nH per foot, into a 5.77 ohm load, the amplifier sees NO CAPACITANCE. NONE. You need to understand this.

When the load becomes higher impedance at higher frequencies, THEN the amplifier will see capacitance. It is a consequence of the line to load mismatch, NOT a consequence of the cable per foot capacitance in isolation.

When the load "unloads" at higher frequencies which are BELOW the amplifier's open loop unity gain bandwidth, the phase margin lowers and the system will be marginally or entirely unstable. A zobel is used to load the line at frequencies the speaker will unload at.

At audio frequencies, if you wish to know what the amplifier "sees" given the line impedance and the load impedance, just calculate the energy stored in the cable.

When line equals load, the inductive and capacitive energy storage will be equal, and it will be a minima. The amplifier will see a resistor.

When the line is much higher than the load, inductive energy storage will dominate.

When the line is much lower than the load, capacitive energy storage will dominate.

And, regardless of the ratio, all energy that is stored in the inductance and capacitance will make it to the load. I know full well where you get this dissipation schtick wit respect to capacitance and inductance, I've seen that site. AND IT"S WRONG. Both storage mechanisms introduce phase lag, not dissipation.

My post consists of technical theory and practice within the disciplines of E/M physics, amplifier design, and human localization. You would be better served asking questions on entities you either lack understanding of, or have a different opinion. Using audio hobbyist website content as technical argument material has it's limits.

Needless to say, you spouting t-line approximations which were taught for the RF guys is a waste of time. You do understand that it is taught that way so that we can use smith charts, right?

Geoff, you crack me up. btw, you never answered my question..how have you been? I hope all is well with you.

jn
2 gurus -> 2 directions.

A limited sample no doubt but extrapolate anyway and why there might be 300 becomes clear.

And that only includes people who might actually know something about this being in scope.

Just stick some flying saucers on the windows and be done with it. :^)
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.