HydrogenAudio

CD-R and Audio Hardware => Audio Hardware => Topic started by: john11 on 2012-11-07 07:31:37

Title: speaker cable
Post by: john11 on 2012-11-07 07:31:37
Hi. And thanks for reading this post.

I have owned quite a few different speaker cables in my time and have always noticed the copper strands of wire within the cable run straight and parallel to each other I.e. they are not twisted. In fact the same is true of mains cable.

Can anyone tell me why this is I was told the electricity has trouble flowing through twisted strands, if each strand was enameled you might get an inductance effect but obviously it is not so the electricity should take the straightest path, so if the strands are twisted or not should have no overall effect.

Can anyone tell me why the copper strands are never twisted.

Thank you in advance. John.
Title: speaker cable
Post by: Garf on 2012-11-07 11:34:22
My understanding is that twisting cables only makes sense if the pair is a differential pair where you're relying on the receiver to do common-mode rejection. Typical speaker cables aren't differential pairs, likely because that's only really needed for HF signals. If the cables aren't differential, twisting can't produce an advantage as it's really spreading the noise over both cables (which eliminates it in a differential pair, but doesn't help in regular cabling).

Balanced pairs are used for audio when the cable needs to be long, and I do believe those are twisted.
Title: speaker cable
Post by: Phlogiston on 2012-11-07 12:15:47
How about twisted cables use more copper and pvc?
Cheaper to make straight / parallel cables
Title: speaker cable
Post by: pdq on 2012-11-07 13:59:51
Twisting the pairs reduces the emission or reception of RF, i.e. frequencies in the many kHz and upward range. The signals to the speakers have no such frequencies, and are not affected by their reception, therefore twisting is not needed and adds an unnecessary expense.

Also, the signal to the speakers is very low impedance and high power, so it would take a very strong interfering signal to have any effect, but being low impedance also means that it has inherently low emission as well.

Besides, there is nothing to prevent one from twisting the speaker cable before connecting it should one desire an extra measure of immunity.
Title: speaker cable
Post by: Speedskater on 2012-11-07 14:46:47
Really all cables be they power, signal interconnects or speaker should be twisted! (save for co-ax)

Jim Brown writes:

Twisting Cable pairs are twisted together for two very important reasons. First, bringing them
more tightly together reduces the coupling of external magnetic fields (while increasing the
coupling between the conductors) by reducing the loop area between them. Second, twisting
them together in a very symmetrical fashion causes any noise coupled onto one conductor to
be more perfectly cancelled (in the receiver) by noise coupled onto the other conductor.
Twisting reduces both magnetic (inductive) and electric (capacitive) coupling.
To understand how twisting does this, consider a magnetic field from a source that is closer to
one side of the cable than the other. At any point along the cable, one conductor will be
closer to the source than the other, so the induced voltage will be greater in that conductor
than in the other. But one half twist along the cable in each direction, the other conductor
will be closer to the source, and so will have the greater induced voltage, but the polarity will
be opposite. The more symmetrical the twisting, and the "tighter" the twisting, the more perfectly
the two induced voltages will match each other over the length of the cable, and thus
be better cancelled by the receiver. The number of twists per unit length is called the "lay" of
the cable.
Twisting also reduces capacitive coupling onto the cable, and for the same reasons. The ability
of twisting to reduce coupling extends to very high frequencies. Ethernet networks run on
high quality, unshielded, twisted pairs at frequencies in the hundreds of MHz, and require
good crosstalk rejection to function well.


Cables, Transmission Lines, and Shielding for Audio and Video Systems
by Jim Brown - Audio Systems Group, Inc.
http://audiosystemsgroup.com (http://audiosystemsgroup.com)

http://audiosystemsgroup.com/TransLines.pdf (http://audiosystemsgroup.com/TransLines.pdf)
Title: speaker cable
Post by: Speedskater on 2012-11-07 14:51:51
Also Henry W. Ott writes about twisted pairs in chapter 2.12 "Coaxial Cable Versus Twisted Pair"  in his big new book.

http://www.hottconsultants.com/EMCE_book_f.../emce_book.html (http://www.hottconsultants.com/EMCE_book_files/emce_book.html)
Title: speaker cable
Post by: pdq on 2012-11-07 15:07:38
I somehow doubt that either of these writers had speaker cables in mind.

I don't know if you will remember this, but in the old days TV antenna lead-ins were typically 300 ohm twinlead, i.e. not coaxial and not twisted pair. It actually was recommended that a few twists be made in the cable where it connected to the outdoor antenna, not for reasons of noise pickup, but because the cable had less tendency to flap in the wind, which could eventually lead to it breaking.
Title: speaker cable
Post by: Apesbrain on 2012-11-07 15:41:24
It's not accurate to say that the "copper strands are never twisted" in speaker cable.  For example, here is a photo of the original Monster Cable:
http://s.shld.net/is/image/Sears/057991910...usm=0.9,0.5,0,0 (http://s.shld.net/is/image/Sears/05799191000?hei=600&wid=600&op_sharpen=1&qlt=90,0&resMode=sharp&op_usm=0.9,0.5,0,0)

Kimber Kable is twisted and twisted again:
http://www.kimber.com/blog/wp-content/uplo...LFOwMmDQ_12.jpg (http://www.kimber.com/blog/wp-content/uploads/2010/01/Bgpv6B2kKGrHqYH-CIEsUOueWWKBLFOwMmDQ_12.jpg)
Title: speaker cable
Post by: mzil on 2012-11-07 15:46:54
Can anyone tell me why the copper strands are never twisted.

Because the relatively strong signal travels a short distance across your living room, so the likelihood of picking up RFI or EMI is rather low. Microphone level, on the other hand, is much weaker and often travels a greater distance, say across a studio or stage, so it benefits from twisting to reduce these potential noise problems, plus it uses a balanced connection for common mode noise rejection.

[For yucks I have twisted my own speaker cable in my youth by placing one end in an electric drill chuck, pulling it almost taut, and then spinning the drill. It was a waste of my time, however, but I was naive.]

When the internal strands of a multi-strand cable twist around each other in a spiral helix, however they touch all the other adjacent strands, it is done simply for for strength, ease of coiling, and flexibility, but the EMI/RFI rejection aspect of a "twisted pair "[with insulation separating them, that is] is gone.
Title: speaker cable
Post by: Speedskater on 2012-11-07 20:27:06
I somehow doubt that either of these writers had speaker cables in mind.
[******]


Really they do include speaker cables!


Twisted Pair Cable I can't say it enough – zip cord is terrible for RFI, and twisted pair solves many
problems. If you have RFI and the cable is anything but coax or a good twisted pair, try to replace
the cable. This is true for virtually all systems – anything from the sensor for a smoke detector to
telephone wiring to big loudspeaker cables. Shielded cable rarely solves RFI problems, partly because
to do anything useful cable shielding must continuous with equipment shielding, and lots of
equipment to which you would like to connect it is unshielded!

A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing

© Entire Contents Copyright 2007-10 The Audio Systems Group, Inc., except Appendices 2, 3, and 4, which are property
of the cited authors, and product data, which is copyright by Fair-Rite Products. All Rights Reserved
by Jim Brown K9YC - Audio Systems Group, Inc.
http://audiosystemsgroup.com (http://audiosystemsgroup.com)

http://www.audiosystemsgroup.com/RFI-Ham.pdf (http://www.audiosystemsgroup.com/RFI-Ham.pdf)
Title: speaker cable
Post by: saratoga on 2012-11-07 21:40:02
Hi. And thanks for reading this post.

I have owned quite a few different speaker cables in my time and have always noticed the copper strands of wire within the cable run straight and parallel to each other I.e. they are not twisted. In fact the same is true of mains cable.

Can anyone tell me why this is I was told the electricity has trouble flowing through twisted strands, if each strand was enameled you might get an inductance effect but obviously it is not so the electricity should take the straightest path, so if the strands are twisted or not should have no overall effect.

Can anyone tell me why the copper strands are never twisted.


You can twist it if you want, but at audio frequencies its not really all that useful, so usually people don't bother paying for it.
Title: speaker cable
Post by: greynol on 2012-11-08 00:56:41
I find that RFI is best reduced if I stand on my head while wiring my speakers.

Seriously, the impedance involved makes this a non-issue. Provide evidence in accordance with TOS8 if you wish to argue otherwise.
Title: speaker cable
Post by: DonP on 2012-11-08 01:22:16
Can anyone tell me why this is I was told the electricity has trouble flowing through twisted strands, if each strand was enameled you might get an inductance effect but obviously it is not so the electricity should take the straightest path, so if the strands are twisted or not should have no overall effect.

Can anyone tell me why the copper strands are never twisted.


All these folks posting about twisted pairs didn't notice he was talking about the strands of each wire being twisted, not the + and - wires being twisted around each other.  Note he mentions current passing between the twists (or not if the strands are insulated).

As in the link to a monster cable pic, they often are twisted.  Sometimes they ARE insulated, look up "litz wire."    I'm not claiming  skin effect is audible in normal speaker cable applications.

Current passing between strands on a twisted wire could be problematic if there is corrosion and a diode forms across the boundary.
Title: speaker cable
Post by: Speedskater on 2012-11-08 02:40:07
I find that RFI is best reduced if I stand on my head while wiring my speakers.

Seriously, the impedance involved makes this a non-issue. Provide evidence in accordance with TOS8 if you wish to argue otherwise.


Wow, the AES committee chair on EMI/RFI is not enough reference by himself?

link added
http://www.aes.org/technical/emc/ (http://www.aes.org/technical/emc/)
Title: speaker cable
Post by: Speedskater on 2012-11-08 02:51:20
From page 2 of the above paper:

Output Wiring is Important Too! It is well known, for example, that RF interference is often coupled
into the output stage of audio equipment – for example, the power amplifiers that feed loudspeakers
or headphones. There is always feedback around that output stage, so RF present at the
output will follow the feedback network to the input of a gain stage, where it will be detected and
amplified. This problem is made much worse when parallel wire cable (zip cord) is used to feed
the loudspeakers or headphones, and can usually be solved simply by replacing the zip cord with a
twisted pair of POC (plain ordinary copper). [Pseudo-scientific advertising hype for exotic cables
notwithstanding, it was shown nearly 30 years ago that #12 copper twisted pair (or #10 for very
long runs) is a nearly ideal loudspeaker cable.] [R. A. Greiner, "Amplifier Loudspeaker Interfacing,”
JAES Vol 28 Nr 5, May 1980] As we will discuss later, the twisting of a pair greatly reduces the
level of RF that the wiring couples to circuitry.

A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing

© Entire Contents Copyright 2007-10 The Audio Systems Group, Inc., except Appendices 2, 3, and 4, which are property
of the cited authors, and product data, which is copyright by Fair-Rite Products. All Rights Reserved
by Jim Brown K9YC - Audio Systems Group, Inc.
http://audiosystemsgroup.com (http://audiosystemsgroup.com)

http://www.audiosystemsgroup.com/RFI-Ham.pdf (http://www.audiosystemsgroup.com/RFI-Ham.pdf)
Title: speaker cable
Post by: quackalist on 2012-11-08 03:49:37
No idea on it's effectiveness or otherwise but its easy enough to DIY if inclined, see:

http://www.youtube.com/watch?v=V6ZecDs0GI4&hd=1 (http://www.youtube.com/watch?v=V6ZecDs0GI4&hd=1)

That example is not very long and you'd need a helper for anything longer.
Title: speaker cable
Post by: greynol on 2012-11-08 04:59:08
Wow, the AES committee chair on EMI/RFI is not enough reference by himself?

Not if we're talking about audible differences in sound quality, no.

I appreciate the insight, however and am glad you've added some actual meat to what was an otherwise egregious appeal to authority. Not that the part I quoted constitutes actual meat (it doesn't).
Title: speaker cable
Post by: julf on 2012-11-08 11:30:29
Seriously, the impedance involved makes this a non-issue.


Well, there is a special case - class D amps (or other amps with a significant HF component in the output or a HF feedback path from the output to the input). Bruno Putzeys of Hypex has a number of times pointed out the importance of twisting the output wires from the hypex amp modules.
Title: speaker cable
Post by: pdq on 2012-11-08 12:54:58
Despite what has been said, high frequencies generated within the power amplifier are not significantly reduced by twisting the conductors of the speaker leads. This kind of noise is primarily single-ended on one speaker lead, and is not cancelled by complementary noise on the other speaker lead. The only viable approach to minimizing this problem is to place an inductor in series with the speaker lead inside of the amplifier.

The company that I work for designs and manufactures non-audio electronic equipment, and does its own testing to pass FCC regulations. I have been involved in design changes when it has been difficult to get a product to pass these tests, so I have a pretty good idea what works and what doesn't.
Title: speaker cable
Post by: greynol on 2012-11-08 14:43:21
Bruno Putzeys of Hypex

Again, what is with the continual presentation of logical fallicies of appealing to authority when what is being requested is objective evidence in accordance with this forum's rules?
Title: speaker cable
Post by: julf on 2012-11-08 14:57:25
Bruno Putzeys of Hypex

Again, what is with the continual presentation of logical fallicies of appealing to authority when what is being requested is objective evidence in accordance with this forum's rules?


Please delete my message. Will repost when I have a chance to post some measurements.
Title: speaker cable
Post by: greynol on 2012-11-08 15:03:09
Do be aware that electrical measurements do not fulfill the requirements of this forum by themselves.
Title: speaker cable
Post by: julf on 2012-11-08 15:17:06
Do be aware that electrical measurements do not fulfill the requirements of this forum by themselves.


In this case I don't think the OP asked about audibility per se. As far as I understand, the question was about possible reasons for cables to be twisted (or not).
Title: speaker cable
Post by: greynol on 2012-11-08 15:23:49
...and that is perfectly OK.
Title: speaker cable
Post by: mzil on 2012-11-08 15:38:01
Beside perhaps Arnold Krueger, who else here owns an ABX comparator box we might ask to try this? Is Bob Lee (of QSC) a forum member here? [I'm not here often enough to know, unless his forum name isn't obvious to me.] If I'm not mistaken, there is no way to apply a software based comparison in this instance, such as what can be done with fb2k.
---

The noise sources I would be inclined to try would be mostly AC hum based. I would try running the speaker wire parallel and adjacent to some long, active AC extension cord I knew didn't have internal, twisted construction itself (over a full room's length, say 20+ ft or so and ideally running a silent, high wattage appliance like a 300W torch lamp), wrapping the speaker wire around a large IE transformer (not toroidal), and also perhaps looping around or over an AC switching power supply such as a modern cell phone wall wart charger (that's not the older, heavy transformer design).

For the musical selection I'd try dead silence with lots of gain, or if that's "not allowed" I'd try some notably quiet passage.
Title: speaker cable
Post by: Speedskater on 2012-11-08 17:18:29
Some "Good Engineering Practices" can not be ABX tested.  When Mr. Brown's papers or Mr. Ott's book write about ways to reduce susceptibility to EMI/RFI no test can be performed that covers all conditions.  You would first have to have a system that is being interfered with (or is your system interfering with something else?) before starting the test. But the possible causes, the possible cures and the possible system configurations is limitless, so our ABX tests will go on forever.
Title: speaker cable
Post by: pdq on 2012-11-08 17:18:39
For the musical selection I'd try dead silence with lots of gain, or if that's "not allowed" I'd try some notably quiet passage.

Changing the gain will have no effect on speaker wires. In fact, perhaps the way to test is with the amplifier turned off. Otherwise you could be detecting noise pickup before the amplifier.
Title: speaker cable
Post by: greynol on 2012-11-08 17:21:43
@mzil:
Do you mean similar to cranking the volume well past normal loud listening levels just to hear fade-outs?
I think that's cheating, though running the amplifier without feeding it content is perfectly OK in my book.

@all:
Would there be anything wrong with recording the output of an amplifier at the speaker terminals with either a load box or with the speakers connected?

@pdq:
Providing two samples, one with twisted cable and one without should suffice, right?
Title: speaker cable
Post by: greynol on 2012-11-08 17:24:27
Some "Good Engineering Practices" can not be ABX tested.  When Mr. Brown's papers or Mr. Ott's book write about ways to reduce susceptibility to EMI/RFI no test can be performed that covers all conditions.  You would first have to have a system that is being interfered with (or is your system interfering with something else?) before starting the test. But the possible causes, the possible cures and the possible system configurations is limitless, so our ABX tests will go on forever.

That is the usual cop-out which gets rejected time and again on this forum.

If you wish to make claims you need to provide proof.  The burden is not on me to prove that such claims could never be right.
Title: speaker cable
Post by: Speedskater on 2012-11-08 17:26:42
For the musical selection I'd try dead silence with lots of gain, or if that's "not allowed" I'd try some notably quiet passage.

Changing the gain will have no effect on speaker wires. In fact, perhaps the way to test is with the amplifier turned off. Otherwise you could be detecting noise pickup before the amplifier.


It would be good to read at lest the first few pages of  Mr. Brown's paper.  (the middle sections of the paper are directed to HAM's and their problems)

What is happening is the interference entries the amp via the speaker wires, then sneaks back to the input stage though the negative feedback network and gets demodulated and amplified.
Mr. Brown explains it much better than that.
Title: speaker cable
Post by: pdq on 2012-11-08 17:43:43
@all:
Would there be anything wrong with recording the output of an amplifier at the speaker terminals with either a load box or with the speakers connected?

You need to be very careful how you record this. A speaker has perfect normal mode rejection so your recording device would need to be as near perfect as you can get to be valid.

OTOH, a speaker does not respond audibly to very small voltages, so the recording device does not need to be very sensitive.
Title: speaker cable
Post by: Speedskater on 2012-11-08 17:45:20
Some "Good Engineering Practices" can not be ABX tested.  When Mr. Brown's papers or Mr. Ott's book write about ways to reduce susceptibility to EMI/RFI no test can be performed that covers all conditions.  You would first have to have a system that is being interfered with (or is your system interfering with something else?) before starting the test. But the possible causes, the possible cures and the possible system configurations is limitless, so our ABX tests will go on forever.

That is the usual cop-out which gets rejected time and again on this forum.

If you wish to make claims you need to provide proof.  The burden is not on me to prove that such claims could never be right.


Well I did not make any claims! I posts short excerpts from the papers of leading experts/authorities in the EMC field.  Mr. Ott's 850 page text book is used in all fields of electronics. Mr. Brown's some 50 papers cover many tests and experiments. I don't think that I could deconstruct how they arrived at those statements.
Title: speaker cable
Post by: pdq on 2012-11-08 17:49:43
What is happening is the interference entries the amp via the speaker wires, then sneaks back to the input stage though the negative feedback network and gets demodulated and amplified.
Mr. Brown explains it much better than that.

I did, in fact, have an experience many years ago in which a neighbor's HAM radio transmitter interfered with my tape recorder (just for a day or two). My understanding at that time (and I had many friends who were HAM radio operators) was that this was probably less of an issue with the tape recorder than that the transmitter was not operating properly. In any case I only experienced it that one time.
Title: speaker cable
Post by: greynol on 2012-11-08 17:58:01
How about mic-ing the speaker then?

This really need not be complex.

AFAIC defending twisting conductor pairs is no different than defending brands of speaker wire.
Title: speaker cable
Post by: mzil on 2012-11-08 20:06:27
@mzil:
Do you mean similar to cranking the volume well past normal loud listening levels just to hear fade-outs?
I think that's cheating, though running the amplifier without feeding it content is perfectly OK in my book.

What I meant is the noise may be very faint. It could easily be masked by compressed rock music or any music without quiet sections.

Unfortunately it may also be easily masked by background, ambient living room noises such as AC, refrigerator, hard drives, cooling fans, furnace, lamp ballast noise, wind, distant traffic/aircraft, birds/crickets, etc.

Better than "turning up the volume knob" would be to sit right next to the speaker with your ear next to it during a quiet passage (or silence if that's allowed). This would allow you to more easily hear a faint added noise either because:

A. "the interference entries the amp via the speaker wires, then sneaks back to the input stage though the negative feedback network and gets demodulated and amplified" as Speedskater mentioned Mr Brown put it.

or

B. It has nothing to do with the amp. [If indeed the faint noise enters the speaker wire and goes straight to the speaker, you will hear it most easily by this method. Very efficient speakers would be best to use for this.]

I'd also like to point out that it should be done with a full range speaker and not a compact monitor. The noise I suspect would be an issue, AC hum, will be at 50 or 60 Hz, which is below the capability of many small speakers. [And obviously if using a modern day AVR it would be important to disengage "bass management" so the main speakers get the full range. No subwoofer should be used.]

I don't own an ABX comparator box nor do I have an environment with a low NR (noise rating), so count me out.
Title: speaker cable
Post by: greynol on 2012-11-08 20:11:10
If it is so faint as to be undetectable other than through extraordinary means, it begs the question as to whether it is really necessary.
Title: speaker cable
Post by: Arnold B. Krueger on 2012-11-08 20:22:58
I have owned quite a few different speaker cables in my time and have always noticed the copper strands of wire within the cable run straight and parallel to each other I.e. they are not twisted. In fact the same is true of mains cable.


You need to get out more. ;-)

Most consumer grade speaker wire I see is indeed composed of parallel conductors as you say. However most speaker wire that is intended for professional use including permanent installation in homes is twisted.

The reasons for this have nothing to do with sound quality.

Twisting and jacketing cables makes it round and easier to install permanently or temporarily.

Twisting cable also decreases its length - the harder you twist it the shorter it gets. So twisting speaker cable increases its resistance per foot slightly, and also makes it a little more expensive to produce.


Quote
Can anyone tell me why this is I was told the electricity has trouble flowing through twisted strands, if each strand was enameled you might get an inductance effect but obviously it is not so the electricity should take the straightest path, so if the strands are twisted or not should have no overall effect.


Whoever told you this is poorly informed.

Twisting speaker cable significantly reduces its self-inductance which can actually build up over long lengths to cause a slight dulling of the highs when the speaker has very low a impedance at high frequencies. So twisting wire can have the opposite effect that was claimed by the person you consulted with.

Neither of the above situations apply to most speaker cables in home audio systems so twisting generally has no effect on reliably audible sound quality.

If speaker cables had high impedance source and load and carried small signals we could get worried about noise pickup which is also reduced by twisting. But speaker cables have low impedance sources and loads and carry relatively large signals, so again twisting  has no significant audible effect in almost all situations.

For the record a passive loudspeaker responds only to the difference of the voltage on its input leads and thus has inherent resistance to common-mode interference. So if it wasn't for the conditions stated in the previous paragraph, twisting could be a good idea for SQ reasons.

Quote
Can anyone tell me why the copper strands are never twisted.


Hard to do because it is simply not true.  ;-)

Here are some examples of twisted and untwisted speaker cable:

http://www.markertek.com/Cables/Bulk-Wire-...able-Bulk.xhtml (http://www.markertek.com/Cables/Bulk-Wire-Cable/Speaker-Wire-Cable-Bulk.xhtml)

Title: speaker cable
Post by: Arnold B. Krueger on 2012-11-08 20:26:39
Really all cables be they power, signal interconnects or speaker should be twisted! (save for co-ax)

Jim Brown writes:

Twisting Cable pairs are twisted together for two very important reasons. First, bringing them
more tightly together reduces the coupling of external magnetic fields (while increasing the
coupling between the conductors) by reducing the loop area between them. Second, twisting
them together in a very symmetrical fashion causes any noise coupled onto one conductor to
be more perfectly cancelled (in the receiver) by noise coupled onto the other conductor.
Twisting reduces both magnetic (inductive) and electric (capacitive) coupling.
To understand how twisting does this, consider a magnetic field from a source that is closer to
one side of the cable than the other. At any point along the cable, one conductor will be
closer to the source than the other, so the induced voltage will be greater in that conductor
than in the other. But one half twist along the cable in each direction, the other conductor
will be closer to the source, and so will have the greater induced voltage, but the polarity will
be opposite. The more symmetrical the twisting, and the "tighter" the twisting, the more perfectly
the two induced voltages will match each other over the length of the cable, and thus
be better cancelled by the receiver. The number of twists per unit length is called the "lay" of
the cable.
Twisting also reduces capacitive coupling onto the cable, and for the same reasons. The ability
of twisting to reduce coupling extends to very high frequencies. Ethernet networks run on
high quality, unshielded, twisted pairs at frequencies in the hundreds of MHz, and require
good crosstalk rejection to function well.


Cables, Transmission Lines, and Shielding for Audio and Video Systems
by Jim Brown - Audio Systems Group, Inc.
http://audiosystemsgroup.com (http://audiosystemsgroup.com)

http://audiosystemsgroup.com/TransLines.pdf (http://audiosystemsgroup.com/TransLines.pdf)



The above issues can be relevant when the signals are small and the impedances are high.

Speakers always have low impedances and always handle among the highest voltages anyplace in an audio system.

So, twisting speaker wires generally has no audible effect.
Title: speaker cable
Post by: Arnold B. Krueger on 2012-11-08 20:33:31
From page 2 of the above paper:

Output Wiring is Important Too! It is well known, for example, that RF interference is often coupled
into the output stage of audio equipment – for example, the power amplifiers that feed loudspeakers
or headphones. There is always feedback around that output stage, so RF present at the
output will follow the feedback network to the input of a gain stage, where it will be detected and
amplified.


The above could possibly be true in a situation like near a high-powered radio transmitter. I've seen some crazy stuff happen in radio stations that had their transmitters in the same room that their announcers worked in. It was probable that a radio station in this dire of a circumstance had some errr, expedient engineering.

Back in a  typical residential situation, it doesn't happen.
Title: speaker cable
Post by: mzil on 2012-11-08 20:50:58
Mr. Krueger, out of curiosity, do you own an ABX comparator box as I suspected earlier?
---

In-wall NEC CL2/3 rated speaker wire is always twisted pairs, at least that I've come across, so I tried to find if that's a stipulation in NEC Article 640, 400, or 725 (http://www.solar365.com/national_electric_code_2008/audio-signal-processing--amplification-and-reproduction-equipment/page/0/6), but my Google powers faded on me so I gave up. [I provide that link in case anyone else wants to run with it.]

Another reason an in-wall wire might be twisted is it then can be encapsulated with another plastic sheath and the circular cross section then becomes easier to fish through holes without getting snagged.

@greynol, I take it you are considering the possibility of recording two segments by tapping the signal at the speaker terminals to then use fb2k ABX, right? [Yes, do that. Don't use a mic.] But my question is how do you time align the two recordings during the playback test? Manually? Restarting from the beginning still may have a "tell", a giveaway, in that the listener would be subconsciously picking up on the different delays before the music starts.
Title: speaker cable
Post by: greynol on 2012-11-08 21:11:23
Again, it it is that faint or subtle it begs the question as to whether it is necessary.
Title: speaker cable
Post by: pdq on 2012-11-08 21:20:36
But my question is how do you time align the two recordings during the playback test? Manually? Restarting from the beginning still may have a "tell", a giveaway, in that the listener would be subconsciously picking up on the different delays before the music starts.

I don't think that anyone is suggesting an effect for which music needs to be playing. To ABX silence vs. silence does not require time aligning.
Title: speaker cable
Post by: mzil on 2012-11-08 21:35:46
^ Some consider silence as a test signal "cheating". For instance, using silence alone will almost always find at least a small difference between the noise floors of things like CD players, preamps, power amps, etc., at least if one is allowed to listen to the residual noise floors and they differ by 1 dB or more.
---

A noise problem which is , oh let's say as a random example, -80 dBFS may not be an issue for some people, in some environments, with some music , but very much of a problem for other people with other music in other environments. I for one would like to know more about what kind of levels we are talking about, if it even is a problem at all, which I never claimed it was.

The problem is also 100% dependent on some noise generator being present, which may only be the case in some of our rooms. Having "no problem at all" now doesn't mean adding, say, a light dimmer in one's wall won't be a big problem a year from now, all because one concluded, "UTP in-wall speaker wire is for the voodoo believing nuts and costs more. I'm going to save money and buy the parallel runs instead".
Title: speaker cable
Post by: pdq on 2012-11-08 21:45:14
There are lots of places in the home audio system where it is conceivable that an external source of noise can become audible. Places where the signal consists of microvolts to millivolts at high impedance levels will always present a potential problem.

However, if you install a dimmer and suddenly you hear a buzzing in your speakers, the speaker wires are the last place to look for a solution. Even expensive line cords are more likely to have a positive effect (and I for one do not advocate expensive line cords).
Title: speaker cable
Post by: greynol on 2012-11-08 21:57:57
^ Some consider silence as a test signal "cheating".

In the event that you used a caret to refer to a previous post, no one claimed using silence as a test signal was cheating.

Rather, it was cranking the volume beyond what you would ever use for listening to real content that was suggested (by me) as cheating.

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Having "no problem at all" now doesn't mean adding a light dimmer in one's wall won't be a big problem a year from now, all because one concluded, "UTP in-wall speaker wire is for the voodoo believing nuts and costs more. I'm going to save money and buy the parallel runs instead".

True, but I find tangible evidence for doing something far more compelling than basing decisions on what I can only describe as fear and paranoia, personally.

EDIT:
In retrospect, I suppose there's nothing wrong with "playing it safe".  Clearly how far one ought to go is a subjective call.
Title: speaker cable
Post by: splice on 2012-11-08 22:31:59
The above could possibly be true in a situation like near a high-powered radio transmitter. I've seen some crazy stuff happen in radio stations that had their transmitters in the same room that their announcers worked in. It was probable that a radio station in this dire of a circumstance had some errr, expedient engineering.

Back in a  typical residential situation, it doesn't happen.


It can happen in a non-typical situation.  At one time I lived in a house that was almost under the antenna of a 2 KW AM broadcast transmitter. It was an inverted L run between 2 towers. It was so close that the wire fell across the house roof one day when it broke at the far end. One set of speaker wires ran under the house to the next room. The leads were twisted, but still injected enough RF to be audible when the phono inputs of the amp were in use. I had to wind about 20 turns of the speaker leads through a large toroid to eliminate it. (The RF field was quite strong, if I hovered the palms of my hands just above the keyboard of my PC it would type random characters..)
Title: speaker cable
Post by: mzil on 2012-11-08 22:35:27
^ Some consider silence as a test signal "cheating".

In the event that you used a caret to refer to a previous post, no one claimed using silence as a test signal was cheating.

Rather, it was cranking the volume beyond what you would ever use for listening to real content that was suggested (by me) as cheating.

I used the caret to mean the post immediately above mine. I'm not very up on forum communication protocols so please feel free to correct my use of that. Did I use it incorrectly?

I didn't mean it had been implied earlier in the thread as being "cheating", I was trying to convey that my experience has been that some people I meet consider the use of silence to be unacceptable and verboten, and I didn't know the policy here. I will try to remember that here it is acceptable with the provision you stated of no artificially loud cranking of the volume knob. Got it.
Title: speaker cable
Post by: greynol on 2012-11-08 22:55:53
It's all good.  I only wanted to make sure I wasn't misunderstood.

My opinion on what is fair and what is not is in no way "official".  I'm really just interested in getting to the bottom to whether we're talking audibility or just an opinion on best-practice.
Title: speaker cable
Post by: aidenn0 on 2012-11-08 23:30:21
I have personally been able to pickup an AM radio station on the speaker cables.  At the time, I was living very close to an AM broadcast tower.  It was only for very quiet sources that I had the problem (since I had the volume turned way up).  I thought for sure that it had to be coming from before the power stage, but the reception varied when moving the speaker cables, and twisting the cables eliminated it.

This was with an RCA amplifier from the late 80s, there may have been something defective in its design; it seem does seem at least theoretically possible that any negative feedback amplifier could do something like this.
Title: speaker cable
Post by: DVDdoug on 2012-11-09 01:05:46
It can happen in a non-typical situation.  At one time I lived in a house that was almost under the antenna of a 2 KW AM broadcast transmitter...

...I had to wind about 20 turns of the speaker leads through a large toroid to eliminate it. (The RF field was quite strong, if I hovered the palms of my hands just above the keyboard of my PC it would type random characters..)
That makes a good point...  In extraordinary circumstances, you might need to take extraordinary measures.  But, there is no reason for 99.99% of us to wrap our speaker wires around a toroid (or to twist our speaker wires).      In fact, somone with a similar problem/symptom might require an entierly different solution.
Title: speaker cable
Post by: Speedskater on 2012-11-09 02:18:18
Some "Good Engineering Practices" can not be ABX tested.  [********}

That is the usual cop-out which gets rejected time and again on this forum.

If you wish to make claims you need to provide proof.  The burden is not on me to prove that such claims could never be right.


OK, I think I see where the problem is.

Nowhere in my excerpts or in the original papers do I or the authors claim that twisted pair cables sound better or even different than any or cable construction.  The only claim is that they reduce the susceptibility to potential interference problems.  This is very different than claiming better sound. 

Each person can have their own view has to how big a potential problem this may be in a specific situation.  But much of both Mr. Brown's and Mr. Ott's career has been spent studying EMI/RFI problems so I'll stick with their recommendations.
Title: speaker cable
Post by: Arnold B. Krueger on 2012-11-09 15:07:11
Mr. Krueger, out of curiosity, do you own an ABX comparator box as I suspected earlier?


Yes, actually several. After all, I invented them!

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In-wall NEC CL2/3 rated speaker wire is always twisted pairs, at least that I've come across, so I tried to find if that's a stipulation in NEC Article 640, 400, or 725 (http://www.solar365.com/national_electric_code_2008/audio-signal-processing--amplification-and-reproduction-equipment/page/0/6), but my Google powers faded on me so I gave up. [I provide that link in case anyone else wants to run with it.]

Another reason an in-wall wire might be twisted is it then can be encapsulated with another plastic sheath and the circular cross section then becomes easier to fish through holes without getting snagged.


Yes, I was trying to allude to that sort of thing. Not about sound quality, its about getting the job done quickly and easily.

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@greynol, I take it you are considering the possibility of recording two segments by tapping the signal at the speaker terminals to then use fb2k ABX, right? [Yes, do that. Don't use a mic.] But my question is how do you time align the two recordings during the playback test? Manually?


Aligning recordings within a few milliseconds is pretty straight forward using any good audio editor.

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Restarting from the beginning still may have a "tell", a giveaway, in that the listener would be subconsciously picking up on the different delays before the music starts.


If you switch quickly,  time offsets of more than a few milliseconds are heard as an echo.  If you don't switch quickly, listener sensitivity to small differences is hurt.
Title: speaker cable
Post by: Porcus on 2012-11-10 12:57:41
This is a thread where I think the references to TOS#8 are not appropriate.
- First, the OP's question was why (s)he has hardly seen twisted speaker cables – even if the explanation were to serve sound quality, that is not a TOS#8 issue (TOS#8 would apply to a claim that it does in fact make a difference, not to intention). Now AFAIK there are quite a lot of twisted speaker cables, but the factual issue does not introduce any TOS#8 relevance.
- Second, suppose you have a case at hand where construction principles do matter sometimes but rarely – but can be safeguarded against, with a tried and tested construction at the extra cost of a cup of coffee? If the purpose is to save you from having to do the same job twice, why require that the job is done twice and then tested for difference?

(Would I get RFID issues by using a nonshielded cable from antenna? Anyone?)


(The RF field was quite strong, if I hovered the palms of my hands just above the keyboard of my PC it would type random characters..)


  Did you wear your tin foil hat? 
Title: speaker cable
Post by: greynol on 2012-11-10 15:52:26
Post #5 was a bit of a borderline case.  It was stated that one always should twist + and - conductors in order to reduce noise with what to me appears to be a clear implication that it will affect sound quality (why else would you care?). Post #10 did temper it by rephrasing to "if you have a interference problem," however.
Title: speaker cable
Post by: splice on 2012-11-11 01:11:09
  Did you wear your tin foil hat? 


I did wear my hard hat the day the antenna wire broke and fell on the house. It also trailed across the long grass next to the driveway and charred it, and I had to put a chair out on the access road to prevent anyone driving over the wire. Because it broke at the far end, the transmitter was still more or less correctly loaded so it didn't trip out. I had trouble convincing the studio that it had broken, they could still hear it OK on their off-air monitor. 

My 2 cents worth on the speaker cable issue: Twisting won't hurt, but it won't make any difference from an audio quality point of view. There may be situations where it might reduce interference etc.
Title: speaker cable
Post by: Porcus on 2012-11-11 10:49:43
Twisting cable also decreases its length - the harder you twist it the shorter it gets. So twisting speaker cable increases its resistance per foot slightly, and also makes it a little more expensive to produce.


Even 'non-twisted' ordinary stranded speaker cables often have each channel twisted around itself. I suppose that the spring effect is what makes them more resistant against a jerk (pun intended).
Title: speaker cable
Post by: splice on 2012-11-11 22:40:37
... Even 'non-twisted' ordinary stranded speaker cables often have each channel twisted around itself. I suppose that the spring effect is what makes them more resistant against a jerk (pun intended).


That's a manufacturing issue. The individual strands are twisted to keep them in a round planform so the sheath can be extruded over them