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speaker cable, why is it never twisted
john11
post Nov 7 2012, 08:31
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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.
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Speedskater
post Nov 8 2012, 03:51
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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://www.audiosystemsgroup.com/RFI-Ham.pdf


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Arnold B. Kruege...
post Nov 8 2012, 21:33
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QUOTE (Speedskater @ Nov 7 2012, 21:51) *
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.
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splice
post Nov 8 2012, 23:31
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QUOTE (Arnold B. Krueger @ Nov 8 2012, 13:33) *
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..)


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Porcus
post Nov 10 2012, 13:57
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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?)


QUOTE (splice @ Nov 9 2012, 00:31) *
(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..)


ohmy.gif Did you wear your tin foil hat? laugh.gif

This post has been edited by Porcus: Nov 10 2012, 13:58


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splice
post Nov 11 2012, 02:11
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QUOTE (Porcus @ Nov 10 2012, 05:57) *
ohmy.gif Did you wear your tin foil hat? laugh.gif


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.


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Don Hills
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Posts in this topic
- john11   speaker cable   Nov 7 2012, 08:31
- - Garf   My understanding is that twisting cables only make...   Nov 7 2012, 12:34
- - Phlogiston   How about twisted cables use more copper and pvc? ...   Nov 7 2012, 13:15
- - pdq   Twisting the pairs reduces the emission or recepti...   Nov 7 2012, 14:59
- - Speedskater   Really all cables be they power, signal interconne...   Nov 7 2012, 15:46
|- - Arnold B. Krueger   QUOTE (Speedskater @ Nov 7 2012, 09:46) R...   Nov 8 2012, 21:26
- - Speedskater   Also Henry W. Ott writes about twisted pairs in ch...   Nov 7 2012, 15:51
- - pdq   I somehow doubt that either of these writers had s...   Nov 7 2012, 16:07
|- - Speedskater   QUOTE (pdq @ Nov 7 2012, 10:07) I somehow...   Nov 7 2012, 21:27
- - Apesbrain   It's not accurate to say that the "copper...   Nov 7 2012, 16:41
- - mzil   QUOTE (john11 @ Nov 7 2012, 03:31) Can an...   Nov 7 2012, 16:46
- - saratoga   QUOTE (john11 @ Nov 7 2012, 03:31) Hi. An...   Nov 7 2012, 22:40
- - greynol   I find that RFI is best reduced if I stand on my h...   Nov 8 2012, 01:56
|- - Speedskater   QUOTE (greynol @ Nov 7 2012, 19:56) I fin...   Nov 8 2012, 03:40
||- - greynol   QUOTE (Speedskater @ Nov 7 2012, 18:40) W...   Nov 8 2012, 05:59
|- - julf   QUOTE (greynol @ Nov 8 2012, 01:56) Serio...   Nov 8 2012, 12:30
|- - greynol   QUOTE (julf @ Nov 8 2012, 03:30) Bruno Pu...   Nov 8 2012, 15:43
|- - julf   QUOTE (greynol @ Nov 8 2012, 15:43) QUOTE...   Nov 8 2012, 15:57
- - DonP   QUOTE (john11 @ Nov 7 2012, 03:31) Can an...   Nov 8 2012, 02:22
- - Speedskater   From page 2 of the above paper: Output Wiring is ...   Nov 8 2012, 03:51
|- - Arnold B. Krueger   QUOTE (Speedskater @ Nov 7 2012, 21:51) F...   Nov 8 2012, 21:33
|- - splice   QUOTE (Arnold B. Krueger @ Nov 8 2012, 13...   Nov 8 2012, 23:31
|- - DVDdoug   QUOTE (splice @ Nov 8 2012, 14:31) It can...   Nov 9 2012, 02:05
|- - Porcus   This is a thread where I think the references to T...   Nov 10 2012, 13:57
|- - splice   QUOTE (Porcus @ Nov 10 2012, 05:57) Did...   Nov 11 2012, 02:11
- - quackalist   No idea on it's effectiveness or otherwise but...   Nov 8 2012, 04:49
- - pdq   Despite what has been said, high frequencies gener...   Nov 8 2012, 13:54
- - greynol   Do be aware that electrical measurements do not fu...   Nov 8 2012, 16:03
|- - julf   QUOTE (greynol @ Nov 8 2012, 16:03) Do be...   Nov 8 2012, 16:17
- - greynol   ...and that is perfectly OK.   Nov 8 2012, 16:23
- - mzil   Beside perhaps Arnold Krueger, who else here owns ...   Nov 8 2012, 16:38
|- - pdq   QUOTE (mzil @ Nov 8 2012, 10:38) For the ...   Nov 8 2012, 18:18
|- - Speedskater   QUOTE (pdq @ Nov 8 2012, 12:18) QUOTE (mz...   Nov 8 2012, 18:26
|- - pdq   QUOTE (Speedskater @ Nov 8 2012, 12:26) W...   Nov 8 2012, 18:49
- - Speedskater   Some "Good Engineering Practices" can no...   Nov 8 2012, 18:18
|- - greynol   QUOTE (Speedskater @ Nov 8 2012, 09:18) S...   Nov 8 2012, 18:24
|- - Speedskater   QUOTE (greynol @ Nov 8 2012, 12:24) QUOTE...   Nov 8 2012, 18:45
|- - Speedskater   QUOTE (greynol @ Nov 8 2012, 12:24) QUOTE...   Nov 9 2012, 03:18
- - greynol   @mzil: Do you mean similar to cranking the volume ...   Nov 8 2012, 18:21
|- - pdq   QUOTE (greynol @ Nov 8 2012, 12:21) @all:...   Nov 8 2012, 18:43
|- - mzil   QUOTE (greynol @ Nov 8 2012, 13:21) @mzil...   Nov 8 2012, 21:06
- - greynol   How about mic-ing the speaker then? This really n...   Nov 8 2012, 18:58
- - greynol   If it is so faint as to be undetectable other than...   Nov 8 2012, 21:11
- - Arnold B. Krueger   QUOTE (john11 @ Nov 7 2012, 02:31) I have...   Nov 8 2012, 21:22
|- - Porcus   QUOTE (Arnold B. Krueger @ Nov 8 2012, 22...   Nov 11 2012, 11:49
|- - splice   QUOTE (Porcus @ Nov 11 2012, 02:49) ... E...   Nov 11 2012, 23:40
- - mzil   Mr. Krueger, out of curiosity, do you own an ABX c...   Nov 8 2012, 21:50
|- - pdq   QUOTE (mzil @ Nov 8 2012, 15:50) But my q...   Nov 8 2012, 22:20
|- - Arnold B. Krueger   QUOTE (mzil @ Nov 8 2012, 15:50) Mr. Krue...   Nov 9 2012, 16:07
- - greynol   Again, it it is that faint or subtle it begs the q...   Nov 8 2012, 22:11
- - mzil   ^ Some consider silence as a test signal "che...   Nov 8 2012, 22:35
|- - greynol   QUOTE (mzil @ Nov 8 2012, 13:35) ^ Some c...   Nov 8 2012, 22:57
|- - mzil   QUOTE (greynol @ Nov 8 2012, 17:57) QUOTE...   Nov 8 2012, 23:35
- - pdq   There are lots of places in the home audio system ...   Nov 8 2012, 22:45
- - greynol   It's all good. I only wanted to make sure I w...   Nov 8 2012, 23:55
- - aidenn0   I have personally been able to pickup an AM radio ...   Nov 9 2012, 00:30
- - greynol   Post #5 was a bit of a borderline case. It was st...   Nov 10 2012, 16:52


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