In instrumentation systems, where accuracy is important, the valid approach is to consider the level of accuracy required. We always are making the trade-off of accuracy versus cost versus the needed accuracy. And as soon as any signal is converted to a digital mode it is no longer exact, Digitized data all changes in finite steps, and thus is very seldom exact.Fortunately it happens that at some easy to reach point, the system is "accurate enough," and the error does not matter. In some systems that is +/- 3%, while in most it is +/- 1%, and in the most precision systems it is +/- 0.1%.
What this implies for speaker connections is that while there may be a difference that could be measured with some very high resolution instrumentation, it is not enough to be noticed by any human. AND, unless one is choosing to listen to ultra-low-distortion sine waves, the remaining effect is far less than the original source variability.

 

I am sorry if I am asking very basic question.
Twisted/Parallel wire inductance calculators assume that the currents in the wires are in opposite direction, and the inductance per unit length is almost constant.
In your example of 10 parallel wires, is not the current in the same direction? In such a case, the geometry of the wire bunch, mutual inductance, ...?

 

The inductance of a group of wires does not depend on what current is flowing through those wires. The effect of the magnetic fields produced by those currents is different from the inductance. Perhaps it would be useful to consider what are the actual currents flowing in the wires. What sound pressure levels are the listeners experiencing? Is the sound level 60 dB or 120 dB? just exactly what are the frequencies involved?

Now here are some quotes:

"Let's calculate using 9 gauge wire with descent insulation. Inductance is going to be around 3500 nh for 10 feet. At 20khz the reactance is approximately 0,44 ohms." Xl = 2P1FL=6.28 X20,000X0.000,0035=.0004396 ohms, which is 0.43 MILLIohms.
Thus I am suspecting a math error in this one.

"In some 4 years of testing with consumers, I have been changing the value of a 9k ohm resistor (placed across a full range driver) by some 0,02 ohms, and individuals have perceived a sonic difference, mainly how bright, clarity, and the attack times (rise times)." And with this claim, consider that if the speaker impedance is actually 8 ohms, and the alleged 9000 ohm resistor is neither capacitive nor inductive, the new resistance is R1R2/ R1 +R2= 8 X 9000/ 8+9000=72000/9008=7.9928952 ohms=99.91119% of the original 8.00000ohms. I challenge anybody to even measure that change, let alone detect it in a properly carried out double-blind evaluation.

So just as there is not much to be gained by arguing with religious zealots, there is nothing to be gained from arguing with those convinced audiophiles, unless one is selling them something.

 

Audioguru concern about harmonics up to 300kHz. They believe they feel them.
It is why they afraid even smallest inductance of speaker wires.

I am Audioguru and I am not an audiophool, instead I am an audiophile.
Most high quality speakers do not produce frequencies above 20kHz. The reactance caused by the inductance of lampcord cable at 20kHz feeding an 8 ohm speaker is so small that you certainly will not hear or "feel" it and you might not be able to measure a slight difference with or without it.

 

I am Audioguru and I am not an audiophool, instead I am an audiophile.
Most high quality speakers do not produce frequencies above 20kHz. The reactance caused by the inductance of lampcord cable at 20kHz feeding an 8 ohm speaker is so small that you certainly will not hear or "feel" it and you might not be able to measure a slight difference with or without it.

I would also say that you have a good grasp on reality, which is pleasant to come across in some of these discussions. Some effects may actually be big enough to be measurable if one has adequate instruments to measure it. Those would include the 18 digit voltmeters that are available but mostly nobody needs them. But reading the change in the fourth order harmonic of a 5KHZ audio signal is going to be a serious challenge for anybody, especially with the rest of an orchestra playing.

 

Of course target of every engineer is to reduce the effects of parasitic reactance and capacitance.

But, taking into account the cost, time, effort and resulting benefits, one has to choose what to do or to what extend.

There is a limit where human ears can detect good, better best and supernatural. Double blind test should be executed to prove what is worth doing and paying.

But as an engineer, I have to make choices based on the above. Despite the above, if the client wants pearls on the cables, its his/her money to spend freely. What else you can do?

Ioannis

 

Though I'm late to this discussion there are some important things to ponder. Twisting of wires is to reduce the pickup of noise caused by E fields not H fields. This is primarily due to the fact that with RF, E fields are much stronger than H fields. I refer to this quote from a post in the Physics Stack Exchange:

In EM radiation, the magnetic field is 3 X 10^8 times smaller than the electric field, but is it valid to say it's "weaker". These fields have different units, so I don't think you can compare them, but even so it seems like we only interact with the electric field of EM radiation, not the magnetic field.

 

Hello,
Please, Please, Please.....
State the problem you are trying to solve, FIRST, instead of making everybody guess what you are doing.
I am a genius Audio Engineer with ~50 years experience.
I am going to assume that you are trying to build a state of the art home stereo sound system,
and you have been trying to collect information on how to put together the best possible system.
If this is the case, you have been looking in the wrong places.
I will lay-out the most important rules for doing this as follows.......
1) The ROOM the System will be set up in IS FAR MORE IMPORTANT than ANY OTHER PART of the system.
The room needs to be as "dead" as possible, and as far from being a "cube" as possible.
Hard Flat Surfaces are always bad, and should be broken-up as much as possible, this includes the floor and ceiling.
If you can't get away from being in a small box, (a cube), put the speakers in the corners, at the ceiling.
Place Rolls of Fiber-Glass Building insulation, still in the plastic bag it came in,
on the floor, IN THE CORNERS of the room.
You can stack these rolls to the ceiling for better effect, but KEEP THEM IN THE CORNERS.

Now that you have done a very rudimentary job of reducing the largest source of distortion,
You can move on to the next largest source of distortion, the speakers.

2) The Speakers very likely have upwards of ~15 to ~30% THD, and, Transient Response Distortion.
The Harmonic distortion is usually fairly straight forward, and well understood by many people,
however, Transient Response Distortion is largely ignored,
especially in the low frequencies, but IT IS EXTREMELY IMPORTANT, AND VERY NOTICEABLE.
In selecting the various methods that you may entertain in designing a speaker system,
there are certain basic things to be avoided......
a) Passive Crossover Networks, I don't care how well engineered they are,
they still can't touch an Active Electronic Crossover, and multiple Amplifiers, PERIOD.
This is called "Bi-Amping", or, "Tri-Amping", or even, "Quad-Amping".

b) Long Speaker Wires, bad idea, but not for any of the reasons you may think.
3- ~$30.oo "Chip-Amps", or, "Plate-Amps", built into the speaker cabinet will have higher fidelity than
1- ~$3,000.oo "Audiophile Grade" amplifier running through ~60 feet of any kind of speaker wire,
with "Passive Crossovers" inside the Speaker Cabinets.
Just not quite as sexy looking.
Note: High Quality TV Cable, (Coaxial Cable), works really well for long "Line-Level" Audio Patch Cords,
and, "RCA- style" Jacks are readily available for making your own long TV Cable Patch Cords.
In any case, long speaker wires should be avoided whenever possible.

c) "Ported", or "Bass-Reflex" Cabinets.....
Automatic High Levels of Transient Distortion, which is "baked-into" the design, and can not be fixed.

3) A properly designed Fully Horn Loaded Speaker can not be touched by any other design,
they are also the most efficient, and have the lowest distortion, (as long as you follow the exact rules).
However, they can get quite large in the lower frequency ranges.
This is part of the reason for mounting your Sealed, "Acoustic-Suspension" Speakers
in the corners near the ceiling, this makes the room function "sorta-kinda-like" a horn-loaded speaker,
but there are other significant advantages to this position as well,
some of which, help to mitigate the numerous problems caused by being inside of a cube.

4) Speaker Stands, and/or, Spiked Feet, are just expensive gimmicks.
Put Rubber Feet on your Speaker Cabinets, or set them on a folded Terry-Cloth Bath Towel.
A Sound System will ALWAYS have higher fidelity when against a wall,
as opposed to anywhere out away from the walls,
and ideally, in a corner,
and even more ideally, tight in a corner, and tight up against the ceiling.

Speaker Positioning will definitely change the Frequency Response of the Speakers,
but normally, the thing that changes the most is the resonances in the room,
and how vigorously they are being excited, or even absorbed by, the speakers position,
AND, the particular frequencies being actively produced by the Speaker,
AND, where in the Room you are taking the measurement.
This goes back to FIXING THE ROOM FIRST.
DON'T BLAME THE SPEAKERS UNTIL THE ROOM IS FIXED.

If you don't like the way your speakers sound,
FIX THE ROOM FIRST !!!!!!!!! ,
FIX YOUR SPEAKERS SECOND !!!!!!!!! ,
then purchase a Stereo 27 Band Graphic EQ, ($150 to $300), and learn how to use it.
It will take at least ~100hours to get the results close to what you want consistently,
and around ~5 years to get really competent at using one,
and recognizing WHAT and WHERE the source of the problem is that you are trying to fix.

Thinking that Speakers are necessarily "better" if they
have "Billiard Table Flat" Frequency Response, is a joke that many
"AudioPhools" fall for.
A Speaker with very low THD, and excellent Transient Response,
but possibly questionable, or even "poor", Frequency Response,
can easily be tweaked (with a 27 Band EQ) into
an EXCELLENT, and very High Fidelity, Sound System.
It's easy to fix Frequency Response,
but not so easy to fix various forms of distortion.

So, Remember........
The ROOM is the "A-NUMBER-ONE" PRIORITY,
Low Distortion, Fast Transient Response Speakers are second,
Learning how it all works and WHAT IS IMPORTANT, (or not), is third,

Expensive Amplifiers, Cables, Wires, and other accessories, are mostly "Eye Candy".
( I like "Eye-Candy", but it does not add any other value, and is usually absurdly expensive ).

Rules for Speaker Wires......
Use "Zip-Cord", "Twin-Lead", "Lamp-Cord", available at Home Depot or Loews,
available in 18, 16, and 14 gauges, and in large sized spools.
Special Flat Cable is available for running under carpets, but it's very expensive.
Less than 10 feet, = 18ga. or larger,
10 to 20 feet, 16ga. or larger,
20 to 30 feet, 14ga. or larger,
over 30 feet, MOVE THE AMPLIFIERS CLOSER TO THE SPEAKERS.
Or, put the Amplifiers inside the Speaker Cabinets.
On 20 to 30 foot runs, up to 10ga. wire can sometimes be useful,
which is then spliced into smaller wires a few feet from the Amplifier, and a few feet from the Speaker,
for convenience in connecting to smaller Terminals.
Using the above rules for Speaker Wires...........
Inductance, Capacitance, "Skin-Effect", "Oxygen-Free-Copper", Twisted, or not,
"Gold-Plated Terminals", Etc, Etc, Etc, IS ALL PROMOTIONAL HYPE, and completely irrelevant.

NEVER use Solid Core Wire FOR ANYTHING associated with Audio,
it WILL break, and/or, cause bad connections, every time.
The above Coaxial Cable Patch Cables are only an exception when
they will not be subjected to movement or vibration near the Connectors.
.
.
.

 

"Speaker Cable should always be twisted. Witnessed a System with Parallel wire (Zip Cord) in a home where the receiver and all electronics were unplugged and removed or un-wired from the speaker wires and yet the speakers were clear as a bell still working. While the volume was very low, the home owner was distressed as they could always hear it. Why? Well because the home was wired with UN-Twisted speaker wire and the AM radio station in town was being received by the long wire antenna (Speaker Wire) and transduced in the speakers. So yes ALL Speaker/Audio wire should be Twisted. "
https://electronics.stackexchange.c...hielded-untwisted-pair-cabling-fine-for-audio
I am sorry, calculator in previous link is not working.
Here is working one: http://www.multek.se/index.php?page=twisted-pair-impedance

Hi. I know this post is old but I haven’t yet figured out how to start my own thread of conversation. I am new to electrical circuit design and I’m building a variable speed drive for a 130 VDC treadmill motor, using a SCR. I have some questions.
I’m running 120 VAC and 130 VDC wires together and I’m wondering if that’s ok. These wires are connected to the motor. AC for thermal protection and DC for the motor itself. They will be in a 4 core un-shielded cable with a 4 pin aviation connector on each end.
I also have another cable that carries hot, neutral, ground for 120 vac, and two thin wires for a potentiometer. I’m using aviation connectors on each end.
I’m basically wondering what the best way is to run AC, DC, and sensor signals together.
Thanks,
Paul

 

Welcome to AAC!
First, a motor drive system is many orders of magnitude less sensitive to distortion than an audiophile system, whose users/owners can usually detect 0.001% distortion in most musical reproduction systems.
Consider the application of those wires and the impedance of the drivers and loads. The 120VAC probably connecting to an over- temperature switch and the DC driving motor coils. When the electrical insulation is adequate for the voltages used, there will be no interaction between the systems.
For the portion of the system with the potentiometer circuit and the AC mains circuit, usually shielded wire is used for signal wiring. At least that is what I have done for industrial control and measurement systems over the years. Standard practice is to not run power and signal wires parallel for any distance, to avoid any potential problems. That is because it is far more expensive to fix problems than to avoid them, rather than have any chance of interactions.