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#41
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
On Tue, 19 Oct 2010 19:49:02 -0700, August Karlstrom wrote
(in article ): On 2010-10-19 21:57, Audio Empire wrote: On Tue, 19 Oct 2010 06:48:24 -0700, August Karlstrom wrote That's great. Then we have real expertise here. What I'm/we're trying to find out here is how thin a wire can be before it will make an audible difference in the best possible system - a table like the one in the Wikipedia article but for critical applications. I don't understand the purpose of your query, I guess. [...] If I can use an even thinner and cheaper cable with the same excellent result why shouldn't I choose that one? I find this optimization problem theoretically interesting. /August OK, as an intellectual exercise, maybe, but practically speaking, we're talking pennies of price difference between thinner and thicker. I feel that a little overkill is the lesser of two evils, I guess. |
#42
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
In article ,
Audio Empire wrote: On Tue, 19 Oct 2010 06:47:43 -0700, isw wrote (in article ): If you're being *that* picky, you might want to take skin effect into account, and use nothing larger than about #18 AWG, paralleling to get the resistance down to what you think you need. Isaac "Skin effect" at audio frequencies? You're joking, right? Do the numbers. The skin depth of "ordinary" copper wire is about equal to the radius of #18 wire at 20 kHz. Using larger diameter wire will give you greater resistive losses at high than at low frequencies; using smaller will give you more-or-less equal losses over the audio range. To be sure, the differences are totally inconsequential, but so are many other things that some people insist on spending a lot of money on in their audio systems. If you're going to be picking nits, you should not ignore any... Isaac |
#43
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
On Tue, 19 Oct 2010 18:57:30 -0700, Trevor Wilson wrote
(in article ): Audio Empire wrote: On Tue, 19 Oct 2010 06:47:43 -0700, isw wrote (in article ): If you're being *that* picky, you might want to take skin effect into account, and use nothing larger than about #18 AWG, paralleling to get the resistance down to what you think you need. Isaac "Skin effect" at audio frequencies? You're joking, right? **The skin effect occurs at all frequencies above DC. It is one reason why power utilities are moving to DC transmission of power. That said, for all practical purposes, in the vast majority of normal sound systems, skin effect plays no part. BTW: Skin depth at 20kHz is approximately 0.5mm. You remind me of a guy I used to know who was heavy into DIY audio. He used to build all his own equipment, both tubed and solid-state. He would even buy vintage pieces like Harman-Kardon Citation I preamps and Dynaco PAS-3s and Leak and Quad and McIntosh and Marantz stuff and replace all the old paper and ceramic caps with modern, polypropylene and Polystyrene units and he'd replace all the old carbon composite resistors with modern metal film units. All laudable tasks, indeed. But whether he was rebuilding an old classic or building something from scratch, he insisted on using Mil-Spec ICs and transistors and replacing 10% resistors and capacitors with precision, 1% resistors. I and others tried to tell him that these precision parts were overkill because nothing in these circuits was that critical. In fact, the vintage stuff was only designed to "slide-rule" accuracy, and then rounded up or back to the nearest standard component value. For instance, the maths might give the designer a value of 45,500 Ohms for a certain resistor in the circuit. Well, there is no standard 45,500 Ohm resistor, so the designer will specify 47K because that's a standard value. Even the modern stuff, designed with digital calculators and computers, uses parts rounded to the nearest standard value. But he insisted on a 1% 47K Ohm resistor instead of a 10% 47K Ohm resistor. It made no difference. 10% tolerance parts or 1% tolerance, it all sounded the same. Now an RIAA preamp might have had a more accurate curve using precision parts, but not precision to standard values, but rather precision to the RIAA turnover and rolloff. This guy couldn't see it. I guess using precision parts made him feel better about his creations, because you certainly couldn't hear the difference, or even measure it. If being hung-up on the minutia of speaker cable makes you feel better about your system, then go for it, but when discussing these matters with people less technically proficient than you are, you merely muddy the waters for them. By adding ifs, thens, and buts that simply have little or no meaning to the guy who just wants an adequate pair of 3-5 meter speaker cables for a domestic (nominally) 8 -Ohm speaker system, you just confuse them. |
#44
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
August Karlstrom wrote:
On 2010-10-20 01:06, Trevor Wilson wrote: **Neither you nor I know if the inductance is relevant in teh system, since we do not know the impedance characteristics of the speaker system. I readily admit that it is highly likely that, given a 4 Metre cable run, almost any cable will work, it is appropriate to point out that speaker impedance should be determined before a recommendation can be given. In my case I use a pair of Amphion Helium II. "its plot of impedance magnitude and electrical phase angle reveals the speaker to be very easy to drive, the impedance remaining above 8 ohms for almost the entire audioband" -- John Atkinson at Stereophile http://www.stereophile.com/budgetcom...on/index4.html This is 7ohm load overall minimum and nearly 8ohm at 20KHz. This is benign load, any cable will do for significant (50m!) lengths. rgds \SK -- "Never underestimate the power of human stupidity" -- L. Lang -- http://www.tajga.org -- (some photos from my travels) |
#45
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
"Never underestimate the power of human stupidity" -- L. Lang
I personally drive two pair of 'difficult' speakers: Carver Amazing Silver MKll's and Infinity WTLC's, and have done a fair bit of research. Given what's out there, I put my trust in one of the giants of audio - McIntosh's Roger Russell. This can be found online, and I consider it the 'bible' of speaker wire info - it has served myself and my friends well: http://www.roger-russell.com/wire/wire.htm You simply can't go wrong with this information, and it's easy to understand and apply. Chuckster |
#46
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
"August Karlstrom" wrote in message
... On 2010-10-20 01:06, Trevor Wilson wrote: **Neither you nor I know if the inductance is relevant in teh system, since we do not know the impedance characteristics of the speaker system. I readily admit that it is highly likely that, given a 4 Metre cable run, almost any cable will work, it is appropriate to point out that speaker impedance should be determined before a recommendation can be given. In my case I use a pair of Amphion Helium II. "its plot of impedance magnitude and electrical phase angle reveals the speaker to be very easy to drive, the impedance remaining above 8 ohms for almost the entire audioband" -- John Atkinson at Stereophile http://www.stereophile.com/budgetcom...on/index4.html **With such a benign load, you are not likely to experience any problems with almost any sensible cable over a 4 Metre length. -- Trevor Wilson www.rageaudio.com.au |
#47
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
On Wed, 20 Oct 2010 05:00:29 -0700, isw wrote
(in article ): In article , Audio Empire wrote: On Tue, 19 Oct 2010 06:47:43 -0700, isw wrote (in article ): If you're being *that* picky, you might want to take skin effect into account, and use nothing larger than about #18 AWG, paralleling to get the resistance down to what you think you need. Isaac "Skin effect" at audio frequencies? You're joking, right? Do the numbers. The skin depth of "ordinary" copper wire is about equal to the radius of #18 wire at 20 kHz. Using larger diameter wire will give you greater resistive losses at high than at low frequencies; using smaller will give you more-or-less equal losses over the audio range. To be sure, the differences are totally inconsequential, but so are many other things that some people insist on spending a lot of money on in their audio systems. If you're going to be picking nits, you should not ignore any... Isaac "To be sure, the differences are totally inconsequential". BTW, I probably (due to my cable lab experience) know more about skin effect than anyone here, my incredulity was prompted by the very idea that someone would actually mention skin effect in the context of a speaker wire discussion. You might as well bring-up the Miller effect and it's influence on amplifier performance. It too is totally irrelevant to the user. |
#48
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
In article ,
Audio Empire wrote: On Wed, 20 Oct 2010 05:00:29 -0700, isw wrote (in article ): In article , Audio Empire wrote: On Tue, 19 Oct 2010 06:47:43 -0700, isw wrote (in article ): If you're being *that* picky, you might want to take skin effect into account, and use nothing larger than about #18 AWG, paralleling to get the resistance down to what you think you need. Isaac "Skin effect" at audio frequencies? You're joking, right? Do the numbers. The skin depth of "ordinary" copper wire is about equal to the radius of #18 wire at 20 kHz. Using larger diameter wire will give you greater resistive losses at high than at low frequencies; using smaller will give you more-or-less equal losses over the audio range. To be sure, the differences are totally inconsequential, but so are many other things that some people insist on spending a lot of money on in their audio systems. If you're going to be picking nits, you should not ignore any... Isaac "To be sure, the differences are totally inconsequential". BTW, I probably (due to my cable lab experience) know more about skin effect than anyone here, my incredulity was prompted by the very idea that someone would actually mention skin effect in the context of a speaker wire discussion. You might as well bring-up the Miller effect and it's influence on amplifier performance. It too is totally irrelevant to the user. But not to the designer, while skin effect is inconsequential to both camps *in the context of home audio systems*. As are a lot of other characteristics that get thrown about in r.a.h-e. Interestingly, the electrical power guys have to take skin effect into account too, if their busbars get big enough; it begins to matter at about 4 inches at 60 Hz, AFAIR. Do you mean cable lab experience as in "CableLabs" in Boulder? I've had some interaction with them... Isaac |
#49
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
On 2010-10-20 22:15, Trevor Wilson wrote:
"August wrote in message In my case I use a pair of Amphion Helium II. "its plot of impedance magnitude and electrical phase angle reveals the speaker to be very easy to drive, the impedance remaining above 8 ohms for almost the entire audioband" -- John Atkinson at Stereophile http://www.stereophile.com/budgetcom...on/index4.html **With such a benign load, you are not likely to experience any problems with almost any sensible cable over a 4 Metre length. Yes, and this is most likely true even if I had a speaker with minimum impedance of only four ohms - even a wire as thin as 2x0.75 mm^2 would do. /August |
#50
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
Trevor Wilson wrote:
"August Karlstrom" wrote in message ... On 2010-10-20 01:06, Trevor Wilson wrote: **Neither you nor I know if the inductance is relevant in teh system, since we do not know the impedance characteristics of the speaker system. I readily admit that it is highly likely that, given a 4 Metre cable run, almost any cable will work, it is appropriate to point out that speaker impedance should be determined before a recommendation can be given. In my case I use a pair of Amphion Helium II. "its plot of impedance magnitude and electrical phase angle reveals the speaker to be very easy to drive, the impedance remaining above 8 ohms for almost the entire audioband" -- John Atkinson at Stereophile http://www.stereophile.com/budgetcom...on/index4.html **With such a benign load, you are not likely to experience any problems with almost any sensible cable over a 4 Metre length. You could substitute 40 for 4 and the statement will be true as well. rgds \SK -- "Never underestimate the power of human stupidity" -- L. Lang -- http://www.tajga.org -- (some photos from my travels) |
#51
Posted to rec.audio.high-end
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Maximum wire length is a function of... what?
On Thu, 21 Oct 2010 07:18:13 -0700, isw wrote
(in article ): In article , Audio Empire wrote: On Wed, 20 Oct 2010 05:00:29 -0700, isw wrote (in article ): In article , Audio Empire wrote: On Tue, 19 Oct 2010 06:47:43 -0700, isw wrote (in article ): If you're being *that* picky, you might want to take skin effect into account, and use nothing larger than about #18 AWG, paralleling to get the resistance down to what you think you need. Isaac "Skin effect" at audio frequencies? You're joking, right? Do the numbers. The skin depth of "ordinary" copper wire is about equal to the radius of #18 wire at 20 kHz. Using larger diameter wire will give you greater resistive losses at high than at low frequencies; using smaller will give you more-or-less equal losses over the audio range. To be sure, the differences are totally inconsequential, but so are many other things that some people insist on spending a lot of money on in their audio systems. If you're going to be picking nits, you should not ignore any... Isaac "To be sure, the differences are totally inconsequential". BTW, I probably (due to my cable lab experience) know more about skin effect than anyone here, my incredulity was prompted by the very idea that someone would actually mention skin effect in the context of a speaker wire discussion. You might as well bring-up the Miller effect and it's influence on amplifier performance. It too is totally irrelevant to the user. But not to the designer, Sigh! Of course Miller effect is not irrelevant to a designer, that's why I said "to the user". But it is something that is not only inconsequential to an amplifier's end user (the amp either HAS the bandwidth required, or the input capacitance is so high that it doesn't), it's also beyond his control. The same with skin effect of speaker cable. It's not only inconsequential for the user, but beyond his control as well. Must we be so pedantic? while skin effect is inconsequential to both camps *in the context of home audio systems*. As are a lot of other characteristics that get thrown about in r.a.h-e. It's called obfuscation and whether done maliciously or just to "show off", these irrelevancies don't help people like the OP who ask for help here at all. Interestingly, the electrical power guys have to take skin effect into account too, if their busbars get big enough; it begins to matter at about 4 inches at 60 Hz, AFAIR. Do you mean cable lab experience as in "CableLabs" in Boulder? I've had some interaction with them... No, I mean like the Cable Laboratory at Lockheed Missiles and Space Company, Inc. Where I spent three years doing everything to wire and cable and connectors that it is possible to do. We evaluated wire and cable types for bandwidth, skin effect, insulation integrity, capacitance, inductance, impedance at frequencies from DC to daylight. We also tested cable in a vacuum, cable (and connectors) in a pure oxygen environment, Cable and connectors under high acceleration, high vibration, high temperature, low temperature etc. We tested connector contact resistance (where I learned about Stabilant (Tweek)), connector mating frequency, and reliability, pin contact area, hermetic integrity, etc., etc, etc., ad nauseum. |
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