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#1
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speaker wire vs. lamp cord
for my new Hsu surround sound system, I have to run so long wires. is
14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? Thanks DoctorJ |
#2
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wrote in message
for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? Plan "B" 12 gauge low voltage stranded wire from your local builder's supply or hardware store. Both Home Depot and Lowe's stock it, for example. |
#3
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Not the same as regular lamp cord???
"Arny Krueger" wrote: wrote in message for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? Plan "B" 12 gauge low voltage stranded wire from your local builder's supply or hardware store. Both Home Depot and Lowe's stock it, for example. ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
#4
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In article ,
wrote: for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? Thanks DoctorJ There are only two basic requirements: - The wire's resistance should be very low compared to the speaker's impedance. - The two wires must be as close as possible to each other to reduce inductance. You can check the tables here or Google for other resistance charts. http://documents.epanorama.net/docum...esistance.html How good the wire needs to be depends on the quality of the speaker. Wire resistance reduces dampening of the speaker's own resonations, it's coloring. It's OK to skimp on speakers used for surround effects because they're usually running off a Lo-Fi signal anyways. 1 Ohm loss would be usable for 8 Ohm surrounds. The primary speakers would probably sound best with less than .5 Ohms loss. Solid-core twisted-pair in-wall wire works great too. It's just tough to manage it without securing it every few feet. |
#5
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"Expensive" speaker wire - 12 ga. can be had on the web for as low as $36/100ft. Definitely for less than $50/100ft. An alternative is to parallel one or two pairs of 14 ga. lamp cord to get the same resistance/ft. Easiest way to check is to take one 14 ga. lamp cord and tie the pair at one end together. Do the same with the other end, use it as a single wire. Do the same for the other speaker lead. See if they sound better. You can even tie two lamp cord sections in parallel ( 4 conductors) for each speaker lead and get it down to equal about 10 ga. I did this once and there was an audible improvement. I assume that your Hsu is not a powered unit. On Sat, 18 Sep 2004 19:56:35 -0400, wrote: for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? Thanks DoctorJ |
#6
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wrote in message
Not the same as regular lamp cord??? Heavier gauge. "Arny Krueger" wrote: wrote in message for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? Plan "B" 12 gauge low voltage stranded wire from your local builder's supply or hardware store. Both Home Depot and Lowe's stock it, for example. ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
#7
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"Kevin McMurtrie" wrote in message
In article , wrote: for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? Thanks DoctorJ There are only two basic requirements: - The wire's resistance should be very low compared to the speaker's impedance. - The two wires must be as close as possible to each other to reduce inductance. You can check the tables here or Google for other resistance charts. http://documents.epanorama.net/docum...esistance.html So far so good. How good the wire needs to be depends on the quality of the speaker. Kevin, what is the criteria for speaker wire goodness? Did you say? Wire resistance reduces dampening of the speaker's own resonations, it's coloring. This seems to be said in an inverted way. A wire with low resistance does a better job of accurately delivering the voltage at the output of the amplifier to the speaker terminals. Conversely a wire with high resistance does a poorer job of accurately delivering the voltage at the output of the amplifier to the speaker terminals. IOW, the high resistance wire will add additional voltage variations, that depend on the speaker's own resonance's, among other things. It's OK to skimp on speakers used for surround effects because they're usually running off a Lo-Fi signal anyways. 1 Ohm loss would be usable for 8 Ohm surrounds. The primary speakers would probably sound best with less than .5 Ohms loss. For best results, the loss in the speaker cables should be less than 1-3% of the minimum impedance of the speaker. There's a procedure for sizing speaker wires posted at http://www.pcavtech.com/techtalk/wire_size/index.htm Solid-core twisted-pair in-wall wire works great too. It's just tough to manage it without securing it every few feet. Agreed. |
#8
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wrote in message ... for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? **You don't mention the length of the cable, nor the impedance characteristics of your speaker, so it is impossible for anyone to answer your question. BTW: Good speaker cable (IE: Low resistance/low inductance type) need not be expensive. -- Trevor Wilson www.rageaudio.com.au |
#9
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#10
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In article ,
"Arny Krueger" wrote: "Kevin McMurtrie" wrote in message In article , wrote: for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? Thanks DoctorJ There are only two basic requirements: - The wire's resistance should be very low compared to the speaker's impedance. - The two wires must be as close as possible to each other to reduce inductance. You can check the tables here or Google for other resistance charts. http://documents.epanorama.net/docum...esistance.html So far so good. How good the wire needs to be depends on the quality of the speaker. Kevin, what is the criteria for speaker wire goodness? Did you say? Wire resistance reduces dampening of the speaker's own resonations, it's coloring. This seems to be said in an inverted way. A wire with low resistance does a better job of accurately delivering the voltage at the output of the amplifier to the speaker terminals. Conversely a wire with high resistance does a poorer job of accurately delivering the voltage at the output of the amplifier to the speaker terminals. IOW, the high resistance wire will add additional voltage variations, that depend on the speaker's own resonance's, among other things. No, I meant same thing. Wire resistance lets the speaker do more of what it wants to do electrically and mechanically. You can put a beefy 10 Ohm resistor in series with your speakers to hear an exaggeration of what happens. Generally you loose some bass and get an uneven midrange response. It's OK to skimp on speakers used for surround effects because they're usually running off a Lo-Fi signal anyways. 1 Ohm loss would be usable for 8 Ohm surrounds. The primary speakers would probably sound best with less than .5 Ohms loss. For best results, the loss in the speaker cables should be less than 1-3% of the minimum impedance of the speaker. There's a procedure for sizing speaker wires posted at http://www.pcavtech.com/techtalk/wire_size/index.htm Solid-core twisted-pair in-wall wire works great too. It's just tough to manage it without securing it every few feet. Agreed. |
#11
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Speaker wire is of a finer stran, thus having less resistance. It is
designed to have less reactance over its length. For short distances, you will not hear the difference, between speaker wire, and a heavy duty lamp cord. If you have a descent DVM, you an measure the DC resistance of a pair of wires to start with. Take a 100 ft length, and short the pairs at the far end. At the close end measure its resistance. Do the same for each type. To test for the return loss due to its capacitive reactance, and inductive reactance, you will need a sophisticated setup, using a laboratory reference amplifier, audio sweep generator, 8 ohm 100 W dummy load, and a scope. Connect the 100 foot length of wire to be tested on to the amplifier with the 8 ohm dummy load connected to the far end. Connect the audio sweep generator to the amplifier, and set the sweep output for 20 to 20K at line sync rate. Connect the scope to the other end, and set its scale to be for 1 V-cm AC coupled. Set the scope sync line rate for line sync. Set the scope time base for 50 ms/cm to start with. Turn the system on, and calibrate at 400 Hz to have the scope to full scale P-P. Turn on the sweep mode and observe the flatness of the sweep. You can trim the veneer or timebase on the scope for the best resolving. If you use the delayed sweep option on the scope you will be able to see any segments of the response, and expand on them. After performing the above, you can then compare the different wires to see the effects. You would be surprised to see how the different types of wires perform. If you do the math, you can calculate the Db drops. If you want to get sophisticated using a dual sweep scope, you can get in to working out the phase delay errors and etc. With a distortion analyser, you can also start getting in to the harmonics that the different wires will produce in relation to each other. All of this becomes part of the sound quality. Personally, I would use speaker cord. The cost difference is not something that is going to break the bank, for the possible gain. -- Jerry G. ====== wrote in message ... for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? Thanks DoctorJ |
#12
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"Jerry G." wrote in message ...
Speaker wire is of a finer stran, thus having less resistance. It is designed to have less reactance over its length. This is pure, utter nonsense. The resistance of the wire is determined NOT by the stranding, but by the net wire gauge and the bulk material. Very fine stranded 12 gauge copper wire has the same resistance as coarse stranded 12 gauge copper wire. The primary advnatge afforded by going to the fine stranded version is in mechanical flexibility. It does NOT change the resistance at all. |
#13
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Kevin McMurtrie wrote in message ...
How good the wire needs to be depends on the quality of the speaker. Wire resistance reduces dampening of the speaker's own resonations, it's coloring. Uh, that would be "resonances" and no, unless you are using VERY tiny wire, the resistance of the speaker wire does NOT reduce damping of the only relevant resonance in the speaker, the fundamental mechanical resonance. A couple of important points behind this: 1. By far, the largest source of series resistance that affects the damping of the speaker resonance is NOT the speaker wire, but the very DC resistance of the voice coil in the driver itself. Unless that resistance is reduced A LOT (it's typically on the order of 80% or more of the nominal impedance of the speaker) OR you're using something like 28 gauge wire, the voice coil DC resistance will completely dominate the total series loop resistance and render pretty irrelevant differences in nomimally competently designed and selected speaker cable. Consider, for instance, the difference between a 10 foot run of 16 gauge vs 12 gauge speaker wire. The former will have a total series resistance of 0.08 ohms vs 0.03 ohms. Now, one might that the 12 gauge has about 2.5 times better damping than the 16 gauge, and that would be wrong. If the speaker voice coil has a DC resistance of 6.5 ohms, say, it's the difference then between 6.58 and 6.53 ohms, and now the difference in damping is more on the order of under 1%, hardly relevant. 2. In any case, the effects on damping caused by the speaker wire cannot affect resonances that have no manifestation in the electrical impedance. That means that, for the most part, the ONLY resonance affected is that of the fundamental mechanical resonance of the driver/system. The vast majority of resonance of the sort caused by diaphragm breakup and such are simply untouched by changing the cable, even in the worst scenarios. |
#14
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#15
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"Jerry G." wrote: Speaker wire is of a finer stran, thus having less resistance. No it doesn't. For a given length os wire, the resitance is purely determined by the cross-sectional area. Stranding makes no difference whatever. It is designed to have less reactance over its length. Wrong again ! The inductance is determined by the 'loop area' which again has nothing whatever to do with stranding. Nor will cable capacitance be affected by stranding. The only effect of significance regarding stranding is skin-effect but at audio frequencies about 2mm dia strands can be used without skin effect being an issue IIRC. Graham |
#17
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"Jerry G." wrote in message ... Speaker wire is of a finer stran, thus having less resistance. Could you explain the physics of how this works ? geoff |
#18
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"Jerry G." wrote in message ... Speaker wire is of a finer stran, thus having less resistance. **Nonsense. It is designed to have less reactance over its length. **Not necessarily. Naim cable, for instance, is specifically designed for high inductance. For short distances, you will not hear the difference, between speaker wire, and a heavy duty lamp cord. **It depends on the load and the actual length of the cable. If you have a descent DVM, you an measure the DC resistance of a pair of wires to start with. Take a 100 ft length, and short the pairs at the far end. At the close end measure its resistance. Do the same for each type. To test for the return loss due to its capacitive reactance, and inductive reactance, you will need a sophisticated setup, using a laboratory reference amplifier, audio sweep generator, 8 ohm 100 W dummy load, and a scope. Connect the 100 foot length of wire to be tested on to the amplifier with the 8 ohm dummy load connected to the far end. Connect the audio sweep generator to the amplifier, and set the sweep output for 20 to 20K at line sync rate. Connect the scope to the other end, and set its scale to be for 1 V-cm AC coupled. Set the scope sync line rate for line sync. Set the scope time base for 50 ms/cm to start with. Turn the system on, and calibrate at 400 Hz to have the scope to full scale P-P. Turn on the sweep mode and observe the flatness of the sweep. You can trim the veneer or timebase on the scope for the best resolving. If you use the delayed sweep option on the scope you will be able to see any segments of the response, and expand on them. **YIKES! You like to do things the hard way. It is MUCH easier to do that that. A millivoltmeter (or a CRO) and an oscillator is all you need. Compare the Voltage at 50Hz and 20kHz. Then it is a trivial exercise to determine the reactance of the cable. BTW: Capacitive reactance is is no interest. -- Trevor Wilson www.rageaudio.com.au |
#19
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On Mon, 20 Sep 2004 04:28:14 -0400, "Jerry G."
wrote: Speaker wire is of a finer stran, thus having less resistance. It is designed to have less reactance over its length. For short distances, you will not hear the difference, between speaker wire, and a heavy duty lamp cord. er......******** :-) |
#20
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Stewart Pinkerton wrote in message . ..
On 20 Sep 2004 08:52:44 -0700, (Dick Pierce) wrote: "Jerry G." wrote in message ... Speaker wire is of a finer stran, thus having less resistance. It is designed to have less reactance over its length. This is pure, utter nonsense. The resistance of the wire is determined NOT by the stranding, but by the net wire gauge and the bulk material. Very fine stranded 12 gauge copper wire has the same resistance as coarse stranded 12 gauge copper wire. The primary advnatge afforded by going to the fine stranded version is in mechanical flexibility. It does NOT change the resistance at all. And in fact, if you wanted the lowest possible resistance, you'd use solid-core 12AWG wire, since it doesn't contain any air space within that 12AWG diameter....... Well, actually, no. If it's spec'ed at 12 gauge, the spec comes from the effective conductor cross-sectional area, so that's taken into account. Be that as it may, the difference in resistance if this weren't the case is still MUCH smaller than the total series resistance, dominated as it is, actually overwhe4lmed by the voice coil DC resistance. |
#21
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On Tue, 21 Sep 2004 00:23:59 +0100, Laurence Payne
wrote: On Mon, 20 Sep 2004 04:28:14 -0400, "Jerry G." wrote: Speaker wire is of a finer stran, thus having less resistance. It is designed to have less reactance over its length. For short distances, you will not hear the difference, between speaker wire, and a heavy duty lamp cord. er......******** :-) What, you mean you *will* hear the difference? :-) -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#22
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Dick Pierce wrote:
"Jerry G." wrote in message ... Speaker wire is of a finer stran, thus having less resistance. This is pure, utter nonsense. Maybe he meant resistance to bending :-))) |
#23
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Dick Pierce wrote:
Well, actually, no. If it's spec'ed at 12 gauge, the spec comes from the effective conductor cross-sectional area, so that's taken into account. Be that as it may, the difference in resistance if this weren't the case is still MUCH smaller than the total series resistance, dominated as it is, actually overwhe4lmed by the voice coil DC resistance. I remember reading about speaker cables that caused some amps major grief. I believe it was the Polk speaker cables. I never understood what happened and why. And, if you used those speaker cables today, would the results be the same. Thanks. |
#24
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Not actually nonesense, since the current runs mostly in the surface of the
iwr. Finer strands = more surface are = less resistance. "Dick Pierce" wrote in message om... "Jerry G." wrote in message ... Speaker wire is of a finer stran, thus having less resistance. It is designed to have less reactance over its length. This is pure, utter nonsense. The resistance of the wire is determined NOT by the stranding, but by the net wire gauge and the bulk material. Very fine stranded 12 gauge copper wire has the same resistance as coarse stranded 12 gauge copper wire. The primary advnatge afforded by going to the fine stranded version is in mechanical flexibility. It does NOT change the resistance at all. |
#25
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"John Krieger" wrote in message
Not actually nonsense, since the current runs mostly in the surface of the wire. Finer strands = more surface are = less resistance. Wrong on several grounds. (1) The depth of the conductive layer @ 20 KHz and below is a very significant portion of the thickness of even 12 gauge wire. (2) Secondly, skin effect is based on magnetism. The magnetic lines of force pass among the strands of wire in a cable quite freely. So, merely stranding and bundling or twisting the strands has little effect. Even insulating the individual strands has little effect. If you want to make a cable that has reduced skin effect @20 KHz and below, you have to make a conductor that is hollow and fairly large like a piece of tubing. If stranded wire is used for this to maintain flexibility, it is wound around a fairly large core composed of non-conductive and non-magnetic material. |
#26
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John Krieger wrote:
Not actually nonesense, since the current runs mostly in the surface of the iwr. Finer strands = more surface are = less resistance. This is an A.C. effect that's only relevant at high frequencies. For example, I have just been designing a switch mode power supply operating at 130kHz. The maximum conductor diameter recommended to avoid skin effect at this frequency is 0.4mm. Scale this to audio frequencies and you'll see the nonsence of the finely stranded argument. Low cable impedance is most relevant at LF anyway (damping factor for LF driver ). Furthermore, an internal passive crossover ( as is most usually the case ) presents a much higher impedance to the LF and HF drivers than the amplifier or cable combined ! Graham |
#27
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In article ,
says... John Krieger wrote: Not actually nonesense, since the current runs mostly in the surface of the iwr. Finer strands = more surface are = less resistance. This is an A.C. effect that's only relevant at high frequencies. For example, I have just been designing a switch mode power supply operating at 130kHz. The maximum conductor diameter recommended to avoid skin effect at this frequency is 0.4mm. Scale this to audio frequencies and you'll see the nonsence of the finely stranded argument. Low cable impedance is most relevant at LF anyway (damping factor for LF driver ). Furthermore, an internal passive crossover ( as is most usually the case ) presents a much higher impedance to the LF and HF drivers than the amplifier or cable combined ! Graham Skin effect with all the calculations. http://tinyurl.com/646hb I Care |
#28
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On Tue, 21 Sep 2004 22:32:42 GMT, TonyP
wrote: I remember reading about speaker cables that caused some amps major grief. I believe it was the Polk speaker cables. I never understood what happened and why. And, if you used those speaker cables today, would the results be the same. Highly capacitive cables triggered HF oscillation in amplifiers which were only marginally stable, most notably the Naim NAP250. Avoid Naim amps, and no modern amplfier should have a problem in this regard. OTOH, you don't need such weird cables anyway, except in the most extreme case of say an electrostat speaker driven by more than 30 feet of cable. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#29
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"John Krieger" wrote in message ... Not actually nonesense, since the current runs mostly in the surface of the iwr. Finer strands = more surface are = less resistance. Yep, at 200KHz or so. But these strands are touching, so do not act as individual conductors. geoff |
#30
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"John Krieger" wrote in message ...
"Dick Pierce" wrote in message om... "Jerry G." wrote in message ... Speaker wire is of a finer stran, thus having less resistance. It is designed to have less reactance over its length. This is pure, utter nonsense. The resistance of the wire is determined NOT by the stranding, but by the net wire gauge and the bulk material. Very fine stranded 12 gauge copper wire has the same resistance as coarse stranded 12 gauge copper wire. The primary advnatge afforded by going to the fine stranded version is in mechanical flexibility. It does NOT change the resistance at all. Not actually nonesense, since the current runs mostly in the surface of the iwr. Finer strands = more surface are = less resistance. You're speaking of the "skin effect" and you're wrong on at least two counts. First, the current does NOT run "mostly on the surface" at audio frequencies. Over the vast majority of the bandwidth, the skin effect is negligable. Second, at those significantly higher frequencies where it is appreciable, the stranding of the sort found in speaker canles has no effect, as the current will confine itself to the surface of the entire bundle, making a stranded cable act essentially as a single solid conductor for all intents and purposes. |
#31
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Stewart Pinkerton wrote:
On Tue, 21 Sep 2004 22:32:42 GMT, TonyP wrote: I remember reading about speaker cables that caused some amps major grief. I believe it was the Polk speaker cables. I never understood what happened and why. And, if you used those speaker cables today, would the results be the same. Highly capacitive cables triggered HF oscillation in amplifiers which were only marginally stable, most notably the Naim NAP250. Avoid Naim amps, and no modern amplfier should have a problem in this regard. OTOH, you don't need such weird cables anyway, except in the most extreme case of say an electrostat speaker driven by more than 30 feet of cable. Thanks for the reply. What was the "advantage" of high capacitive cables? |
#32
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On Thu, 23 Sep 2004 01:01:44 GMT, TonyP
wrote: Stewart Pinkerton wrote: On Tue, 21 Sep 2004 22:32:42 GMT, TonyP wrote: I remember reading about speaker cables that caused some amps major grief. I believe it was the Polk speaker cables. I never understood what happened and why. And, if you used those speaker cables today, would the results be the same. Highly capacitive cables triggered HF oscillation in amplifiers which were only marginally stable, most notably the Naim NAP250. Avoid Naim amps, and no modern amplfier should have a problem in this regard. OTOH, you don't need such weird cables anyway, except in the most extreme case of say an electrostat speaker driven by more than 30 feet of cable. Thanks for the reply. What was the "advantage" of high capacitive cables? In general, a cable which exhibits high capacitance will also exhibit low inductance. Low inductance is *theoretically* desirable in a speaker cable, as it reduces the cable reactance at high frequencies. In practice, even driving a 3-ohm load over thirty feet of cable with Naim NACA5 (probably the *highest* inductance cable commonly available) will result in a treble droop of less than 1dB at 20kHz. Some of those low-inductance cables, such as Alpha Core 'Goertz' MI claim to have a 'matched' impedance, as the characteristic impedance of the cable is only 6-8 ohms, as opposed to the 50-100 ohms of most speaker cable. In reality, this is an insupportable argument, since the cable is not being driven from a 6-8 ohm source, speaker impedance varies wildly, and a matched impedance would in any case only be of importance when cable length exceeds about 1/10 of a wavelength. The wavelength of a 20kHz signal in such a cable is about six *miles*.... -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#33
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#34
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Alex Rodriguez wrote:
In article , says... for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? If really long runs, get 12 gauge. With the money you save you can buy some more music to play through your system. ------------ Alex Also note that lamp (zip) cord has a flat edge and a round edge that you can use to maintain (or keep track of) polarity. Ron Capik NJ Pinelands Cultural Society www.AlbertHall.org -- |
#35
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Stewart Pinkerton wrote:
On Thu, 23 Sep 2004 01:01:44 GMT, TonyP wrote: Stewart Pinkerton wrote: On Tue, 21 Sep 2004 22:32:42 GMT, TonyP wrote: Highly capacitive cables triggered HF oscillation in amplifiers which were only marginally stable, most notably the Naim NAP250. Avoid Naim amps, and no modern amplfier should have a problem in this regard. OTOH, you don't need such weird cables anyway, except in the most extreme case of say an electrostat speaker driven by more than 30 feet of cable. Thanks for the reply. What was the "advantage" of high capacitive cables? In general, a cable which exhibits high capacitance will also exhibit low inductance. Low inductance is *theoretically* desirable in a speaker cable, as it reduces the cable reactance at high frequencies. In practice, even driving a 3-ohm load over thirty feet of cable with Naim NACA5 (probably the *highest* inductance cable commonly available) will result in a treble droop of less than 1dB at 20kHz. Some of those low-inductance cables, such as Alpha Core 'Goertz' MI claim to have a 'matched' impedance, as the characteristic impedance of the cable is only 6-8 ohms, as opposed to the 50-100 ohms of most speaker cable. In reality, this is an insupportable argument, since the cable is not being driven from a 6-8 ohm source, speaker impedance varies wildly, and a matched impedance would in any case only be of importance when cable length exceeds about 1/10 of a wavelength. The wavelength of a 20kHz signal in such a cable is about six *miles*.... Thanks again for the reply. I gather then, that, this type of speaker wire offers no real advantage in normal applications, and would not be really cost effective. |
#36
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Ron Capik wrote:
Alex Rodriguez wrote: In article , says... for my new Hsu surround sound system, I have to run so long wires. is 14 gauge lamp cord ok ($25/250 feet) or must it be expensive "speaker wire"?? If really long runs, get 12 gauge. With the money you save you can buy some more music to play through your system. ------------ Alex Also note that lamp (zip) cord has a flat edge and a round edge that you can use to maintain (or keep track of) polarity. Ron Capik NJ Pinelands Cultural Society www.AlbertHall.org -- I've never seen ANY kind of paired wire that didn't have SOME kind of way to distinguish the wires -- color, printing, texture on the insulation, a wrap or thread, etc. -- The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form . |
#37
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On Thu, 23 Sep 2004 23:18:27 GMT, TonyP
wrote: Stewart Pinkerton wrote: On Thu, 23 Sep 2004 01:01:44 GMT, TonyP wrote: Thanks for the reply. What was the "advantage" of high capacitive cables? In general, a cable which exhibits high capacitance will also exhibit low inductance. Low inductance is *theoretically* desirable in a speaker cable, as it reduces the cable reactance at high frequencies. In practice, even driving a 3-ohm load over thirty feet of cable with Naim NACA5 (probably the *highest* inductance cable commonly available) will result in a treble droop of less than 1dB at 20kHz. Some of those low-inductance cables, such as Alpha Core 'Goertz' MI claim to have a 'matched' impedance, as the characteristic impedance of the cable is only 6-8 ohms, as opposed to the 50-100 ohms of most speaker cable. In reality, this is an insupportable argument, since the cable is not being driven from a 6-8 ohm source, speaker impedance varies wildly, and a matched impedance would in any case only be of importance when cable length exceeds about 1/10 of a wavelength. The wavelength of a 20kHz signal in such a cable is about six *miles*.... Thanks again for the reply. I gather then, that, this type of speaker wire offers no real advantage in normal applications, and would not be really cost effective. In so far as it will sound identical to 12AWG zipcord, that would be correct. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
#38
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"Stewart Pinkerton" wrote in message ... On Thu, 23 Sep 2004 01:01:44 GMT, TonyP wrote: Stewart Pinkerton wrote: On Tue, 21 Sep 2004 22:32:42 GMT, TonyP wrote: I remember reading about speaker cables that caused some amps major grief. I believe it was the Polk speaker cables. I never understood what happened and why. And, if you used those speaker cables today, would the results be the same. Highly capacitive cables triggered HF oscillation in amplifiers which were only marginally stable, most notably the Naim NAP250. Avoid Naim amps, and no modern amplfier should have a problem in this regard. OTOH, you don't need such weird cables anyway, except in the most extreme case of say an electrostat speaker driven by more than 30 feet of cable. Thanks for the reply. What was the "advantage" of high capacitive cables? In general, a cable which exhibits high capacitance will also exhibit low inductance. Low inductance is *theoretically* desirable in a speaker cable, as it reduces the cable reactance at high frequencies. In practice, even driving a 3-ohm load over thirty feet of cable with Naim NACA5 (probably the *highest* inductance cable commonly available) will result in a treble droop of less than 1dB at 20kHz. **Except that, with some speakers (notably electrostatics), low inductance cables may well be desirable. Here is the impedance curve of just such a speaker: www.rageaudio.com.au/accu.jpg In this situation, NAIM cables (unless the speaker is to used with a NAIM amplifier) would be the very worst choice imaginable. Standard Figure 8 (Zip cable) would be a slightly less worse choice. High power coax, or Goertz MI-1 would be the best choices. -- Trevor Wilson www.rageaudio.com.au |
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In article ,
"Trevor Wilson" wrote: "Stewart Pinkerton" wrote in message ... On Thu, 23 Sep 2004 01:01:44 GMT, TonyP wrote: Stewart Pinkerton wrote: On Tue, 21 Sep 2004 22:32:42 GMT, TonyP wrote: I remember reading about speaker cables that caused some amps major grief. I believe it was the Polk speaker cables. I never understood what happened and why. And, if you used those speaker cables today, would the results be the same. Highly capacitive cables triggered HF oscillation in amplifiers which were only marginally stable, most notably the Naim NAP250. Avoid Naim amps, and no modern amplfier should have a problem in this regard. OTOH, you don't need such weird cables anyway, except in the most extreme case of say an electrostat speaker driven by more than 30 feet of cable. Thanks for the reply. What was the "advantage" of high capacitive cables? In general, a cable which exhibits high capacitance will also exhibit low inductance. Low inductance is *theoretically* desirable in a speaker cable, as it reduces the cable reactance at high frequencies. In practice, even driving a 3-ohm load over thirty feet of cable with Naim NACA5 (probably the *highest* inductance cable commonly available) will result in a treble droop of less than 1dB at 20kHz. **Except that, with some speakers (notably electrostatics), low inductance cables may well be desirable. Here is the impedance curve of just such a speaker: www.rageaudio.com.au/accu.jpg In this situation, NAIM cables (unless the speaker is to used with a NAIM amplifier) would be the very worst choice imaginable. Standard Figure 8 (Zip cable) would be a slightly less worse choice. High power coax, or Goertz MI-1 would be the best choices. If you actually do the calculations to determine the "characteristic impedance" of a transmission line in the audio frequency range, you might be more than a little surprised. The line doesn't have one; it is frequency dependent, unlike the situation at "RF". See the "Schaum's Outline Series" tutorial on Transmission Lines to learn how to do the calculations correctly. Most "transmission line" texts do not cover how "characteristic impedance" is calculated at low frequencies; that one does .The calculation is nowhere near the same as at higher frequencies. Isaac |
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Isaac Wingfield wrote:
If you actually do the calculations to determine the "characteristic impedance" of a transmission line in the audio frequency range, you might be more than a little surprised. The line doesn't have one; it is frequency dependent, unlike the situation at "RF". That's because audio frequencies have very long wavelengths. Only when the cable length approaches the signal wavelength does a characteristic impedance become a relevant issue. Graham |
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