Johny, I can see your point and I partly agree.
As I see it, people pay for cables not only because they look good, not only because they are expensive, but mainly because they offer performance improvements (as claimed).
Personally, I see ads claiming better performance. Not decoration improvement nor psychological healing.
They also make scientific??? claims about it. They SELL performance above anything else.
So, if they know it is so, I guess it's ok. If on the other hand they know it's not like that, they are commiting a fraud.
What do you guys think?
As I see it, people pay for cables not only because they look good, not only because they are expensive, but mainly because they offer performance improvements (as claimed).
Personally, I see ads claiming better performance. Not decoration improvement nor psychological healing.
They also make scientific??? claims about it. They SELL performance above anything else.
So, if they know it is so, I guess it's ok. If on the other hand they know it's not like that, they are commiting a fraud.
What do you guys think?
I think the number one thing they are selling is satisfaction both visual and mental via a subjective evaluation. It's not possible for that to be fraudulent.
Dear Nelson: On page 4 of your 1980 Speaker Cable article is this paragraph:
"The explanation for this resonance is reasonably simple if we consider
that it takes a certain amount of time for the signal to travel down the
cable. A wave's velocity proportional to its "characteristic impedance,"
Z01 a value expressed in ohms and determined by the inductance and
capacitance:"
It seems there's a missing equation here? Because two paragraphs later it says:
"This mismatch of load impedance to cable impedance causes the
resonance observed in Fig. 8, which we see diminish in Polk and
Mogami cables when they are loaded with 8 ohms, a
value near their characteristic impedance. By
contrast, twin lead conductors have a higher
characteristic impedance and perform better at
multimegaHertz frequencies with about so [50?] ohms load
impedance."
Where does the 8 Ohm and 50 Ohm "characteristic impedance" come from, and how is it important? Should we aim to construct cables that match our nominal speaker impedance?
(I have been digesting this article for almost two decades, but never made it past this part...)
And then later on page 4:
"The effect of twin lead cable on a 5uS
pulse with an 8 ohm load shows the effect of a load
impedance lower than Zo, where the cable
inductance cable rolls off the edges of the pulse, but
where the 8 ohm resistance is sufficient to damp the
ringing which occurs with Z. = 0 or ZL = infinity . Not
so for capacitive loads as shown in the fourth column
where another resonance altogether has developed
due to the inductance of the cable and the
capacitance of the load where:"
There's something important missing here, too?
"The explanation for this resonance is reasonably simple if we consider
that it takes a certain amount of time for the signal to travel down the
cable. A wave's velocity proportional to its "characteristic impedance,"
Z01 a value expressed in ohms and determined by the inductance and
capacitance:"
It seems there's a missing equation here? Because two paragraphs later it says:
"This mismatch of load impedance to cable impedance causes the
resonance observed in Fig. 8, which we see diminish in Polk and
Mogami cables when they are loaded with 8 ohms, a
value near their characteristic impedance. By
contrast, twin lead conductors have a higher
characteristic impedance and perform better at
multimegaHertz frequencies with about so [50?] ohms load
impedance."
Where does the 8 Ohm and 50 Ohm "characteristic impedance" come from, and how is it important? Should we aim to construct cables that match our nominal speaker impedance?
(I have been digesting this article for almost two decades, but never made it past this part...)
And then later on page 4:
"The effect of twin lead cable on a 5uS
pulse with an 8 ohm load shows the effect of a load
impedance lower than Zo, where the cable
inductance cable rolls off the edges of the pulse, but
where the 8 ohm resistance is sufficient to damp the
ringing which occurs with Z. = 0 or ZL = infinity . Not
so for capacitive loads as shown in the fourth column
where another resonance altogether has developed
due to the inductance of the cable and the
capacitance of the load where:"
There's something important missing here, too?
Attachments
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I think what you want to take away from that is if a cable is not terminated
in its "characteristic impedance" there will be a reflection back from the load
which becomes significant at very high frequencies.
These really aren't audio frequencies, but the effects can become quite
audible if the amplifier has very wide bandwidth and is capable of having its
frequency stability disrupted by this reflection. The solution for this is generally
to terminate the speaker end of the cable with an RC network as described
which dissipates some of the energy at a megaHertz and above.
You may recall that this was more of an issue around the time the article
was written when a number of wide-band high-feedback amplifiers were
behaving badly with a new breed of exotic power cables. I haven't seen
much of this lately.
And yes, little bits of the article did not get transcribed...
in its "characteristic impedance" there will be a reflection back from the load
which becomes significant at very high frequencies.
These really aren't audio frequencies, but the effects can become quite
audible if the amplifier has very wide bandwidth and is capable of having its
frequency stability disrupted by this reflection. The solution for this is generally
to terminate the speaker end of the cable with an RC network as described
which dissipates some of the energy at a megaHertz and above.
You may recall that this was more of an issue around the time the article
was written when a number of wide-band high-feedback amplifiers were
behaving badly with a new breed of exotic power cables. I haven't seen
much of this lately.
And yes, little bits of the article did not get transcribed...
Some people may choose not to endorse specific make and model wire for speakers, and I won't begrudge them for that, but I'll go ahead and stick my neck out.
I got a 250 ft roll of 12 Ga. 2 conductor low-voltage Southwire "Landscape Wire" for $80 at Lowe's. I can't endorse the whole roll (yet), but the two 40-foot-long pieces I cut off and connected up work just fine for me.
Here's the manufacturer's link:
http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet246
Depending on what amplifier I use, the 150V (peak? RMS?) voltage rating of the wire might not be enough, but it looks like I should be safe below a kilowatt or so.
I got a 250 ft roll of 12 Ga. 2 conductor low-voltage Southwire "Landscape Wire" for $80 at Lowe's. I can't endorse the whole roll (yet), but the two 40-foot-long pieces I cut off and connected up work just fine for me.
Here's the manufacturer's link:
http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet246
Depending on what amplifier I use, the 150V (peak? RMS?) voltage rating of the wire might not be enough, but it looks like I should be safe below a kilowatt or so.
I have expensive cables at hand and I have dirt cheap ones too. I like them both - for different things. As far as value goes the cheap ones win hands down.
But I'm not in a position to evaluate the companies claims. I haven't studied anything related to physics, mechanics or mathematics. So I can't say.
I think branded cables are overpriced. Even the cheap ones.
I guess though that someone who understands these concepts should be better qualified to understand if there is a scam or if there is a reason.
This is why I'm asking.
Sometimes common sense is not enough by itself. Or maybe it is???
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I use 1/2 mm. going skinnier proves to have reliability issues in my system where things are moved in & out often
dave
I think what you want to take away from that is if a cable is not terminated
in its "characteristic impedance" there will be a reflection back from the load
which becomes significant at very high frequencies.
These really aren't audio frequencies, but the effects can become quite
audible if the amplifier has very wide bandwidth and is capable of having its
frequency stability disrupted by this reflection. The solution for this is generally
to terminate the speaker end of the cable with an RC network as described
which dissipates some of the energy at a megaHertz and above.
You may recall that this was more of an issue around the time the article
was written when a number of wide-band high-feedback amplifiers were
behaving badly with a new breed of exotic power cables. I haven't seen
much of this lately.
And yes, little bits of the article did not get transcribed...
It seems to me that aside from extreme case scenarios like cable terminations causing reflections in turn causing audible amplifier instability, it doesnt matter what cable you use. There is no scientific basis for the audibility of different cables?
maybe we should just go here....
http://www.diyaudio.com/forums/cons...y-contribution-site-if-anyone-interested.html
and be finished with the whole "cable" thingy...
jus' sayin'...
http://www.diyaudio.com/forums/cons...y-contribution-site-if-anyone-interested.html
and be finished with the whole "cable" thingy...
jus' sayin'...
It does, although skin effect doesn't affect the sound by itself
It does affect the variable "sink" of the signal into the depth of the conductor of finite conductivity vs frenquency, resulting in (complexly measurable) (some would say audible) time smear.
In other words, the losses exhibit a rather complex module, instead of beeing practically linear and mostly a resistive part (simpler) character.
A single 0,6 mm dia. copper conductor pfte insulated by polarity can greatly enhance sound results, if used adequately ( Mundorf hollow MCs bananas beryllium copper, silver solder, insulation of copper and solder joints againts corrosion).
Using an ultra-thin but large ( say 0,07mm or 0,05mm x 30mm) foil allows keeping an ever better overall conductor section, preserving good signal intergrity (especially transcients, and precision in the bass levels).
In some designs, where foils are intimately coupled, this can lead to a rather capacitive cable with alomost zero inductance. Those are known to cause stability problems to ultra-high bandwidth amplifiers, or poorly designed ones.
Nelson Pass doesn't aim first to maximize bandwidth of amplifiers up to 1MHz or more in his class A designs, they provide very good stability against those cable designs in general (see the often 100kHz or 200 kHz @ -3 dB). it is always possible to use RC network across speakers terminals to cure eventual problems anyways.
Best,
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