Bongo, I don't know if you settled on a spectrum analyzer yet, but I've used AudioXplorer with some success. Let me know what you end up using.
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Hey nerds! 3 high-quality cables, all sound different--why?
- Thread starter bongomania
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But your op didn't state whether this was a passive bass or active so most people just tried to express the major difference that makes.
No, because I described significant differences between three different cables, and asked why they sound so different--which is completely irrespective of whether I am using an active or a passive bass. The bass can be a "black box". Say I'm using a passive, which interacts more with cables than an active does--all three cables sound significantly different with that same passive bass, and the only difference is the cable. I clearly described how (a) all three cables are claimed to be low-capacitance; (b) one of the cables has what I perceive to be significantly higher treble content; and (c) one of the cables has a completely different perceived effect on the sound, which my (biased, fallible) ears hear as not just a change in the treble content.
I'm not trying to be ornery or complainy about this, it's just that there was a lot of information presented which some posters either didn't bother to read, or where they read it and decided I must be describing a sort of subtle placebo-oriented "different tone" that would be easy for them to dismiss. I do understand and agree with the premise that the bass itself forms a part of an LRC filter, and that this filter may not just have a treble rolloff characteristic.
For the record:
--I plan to buy a new audio interface in the next week or so, depending on sales/coupons/etc. that may come up.
--I will record sound clips with each cable, using an active bass, a passive bass, and a test tone.
--I will "pink noise" all three cables through the spectrum analyzer, and post the results.
--I will also use the active and passive bass signals as test sources, attempting to make them as consistent as possible, and post the spectrum analyzer results.
I'm not trying to be ornery or complainy about this, it's just that there was a lot of information presented which some posters either didn't bother to read, or where they read it and decided I must be describing a sort of subtle placebo-oriented "different tone" that would be easy for them to dismiss. I do understand and agree with the premise that the bass itself forms a part of an LRC filter, and that this filter may not just have a treble rolloff characteristic.
For the record:
--I plan to buy a new audio interface in the next week or so, depending on sales/coupons/etc. that may come up.
--I will record sound clips with each cable, using an active bass, a passive bass, and a test tone.
--I will "pink noise" all three cables through the spectrum analyzer, and post the results.
--I will also use the active and passive bass signals as test sources, attempting to make them as consistent as possible, and post the spectrum analyzer results.
It's nice of you to go to all that trouble. And, it's possible it might get you closer to answering your original question which was "why?"
But, after reading your compressor reviews, I, for one, gather that you have a pretty good ear, and I am willing to take your word for it that the cables sound different. (Also, I had a Fender Premium Gold Bass cable for a while, and to me it sounded different than the cheap cables I normally use.)
Well I spend my days as an electrical engineer so I will throw a few comments. I am by no means an expert in signal integrity of wires though.
An instrument cable are unbalanced, coaxial cable (kind of like a TV cable). The inner wire, which carries the signal, is made of a bundle of strands as opposed to being a single, solid wire. The main reason for this is to allow the wire to be flexible. However, this does introduce on possible variation between cables. Different sized strands could be used to create equivalent cables. So one cable might be made of 20 strands of 24 guage wire and another cable might be made of 30 strands of 28 guage wire.
There is a phenomenon known as skin effect associated with wires also. What happens is that as the frequency of a signal in a wire increases, electromagenetic waves build up causing the electrons to crowd closer and closer to the outer surface of the wire. The result is that the impedance of a wire increases at about square root of the frequency once the skin depth is less than about 1/2 the radius of the wire. If the wires are made of different sized strands, skin effect will effect the cables differently. In general I think at the frequencies we are talking about this probably will have little effect though.
Cables also have a characteristic impedance, capacitance, and inductance associated with them. All of these can also vary from cable to cable. One obvious source of variation would be with different construction materials (purity of metals, coatings on the metals, etc). Another source of variation is the construction of the coax cable itself.
For example, the per-unit-length inductance and capacitance of a coaxial cable vary with rs and rw, where rs is the radius from the center of the wire to the shield and rw is the radius of the center conductor. So if one cable has a bigger distance between the shield and center conductor (or if the size of the center conductor is different) then these value will be different. And I guess when they claim they have a "low capacitance" wire this is what they have done to acheive that. As far as effect, both the capacitance and the inductance will attenuate higher frequencies more than lower frequencies causing a lower volume of high frequency content relative to low frequency content.
Other things that could also have an effect:
The length of the cables. Most of the above things I have talked about are on a per-unit-length basis, so the longer the cable the bigger these values. I am assuming you are using equal length cables if you are doing a comparison like this though.
The connectors. You also have capacitances and inductances in the connectors between the signal and ground that will depend on the distance between these two signals.
Shielding. Depending on how well the cables are shielded and how these shields are grounded could effect noise induced on the cables, but it didn't sound like this was what you were hearing.
Anyway, there aren't any real answers there for you. But that is what I know about wires that could be causing the differences you hear. As for what is causing the difference the best way I know to tell the difference is to figure out what the physical differences between the wires are either through obtaining drawings of the cables (if the manufacturers will give these out) or tearing them down yourself.
An instrument cable are unbalanced, coaxial cable (kind of like a TV cable). The inner wire, which carries the signal, is made of a bundle of strands as opposed to being a single, solid wire. The main reason for this is to allow the wire to be flexible. However, this does introduce on possible variation between cables. Different sized strands could be used to create equivalent cables. So one cable might be made of 20 strands of 24 guage wire and another cable might be made of 30 strands of 28 guage wire.
There is a phenomenon known as skin effect associated with wires also. What happens is that as the frequency of a signal in a wire increases, electromagenetic waves build up causing the electrons to crowd closer and closer to the outer surface of the wire. The result is that the impedance of a wire increases at about square root of the frequency once the skin depth is less than about 1/2 the radius of the wire. If the wires are made of different sized strands, skin effect will effect the cables differently. In general I think at the frequencies we are talking about this probably will have little effect though.
Cables also have a characteristic impedance, capacitance, and inductance associated with them. All of these can also vary from cable to cable. One obvious source of variation would be with different construction materials (purity of metals, coatings on the metals, etc). Another source of variation is the construction of the coax cable itself.
For example, the per-unit-length inductance and capacitance of a coaxial cable vary with rs and rw, where rs is the radius from the center of the wire to the shield and rw is the radius of the center conductor. So if one cable has a bigger distance between the shield and center conductor (or if the size of the center conductor is different) then these value will be different. And I guess when they claim they have a "low capacitance" wire this is what they have done to acheive that. As far as effect, both the capacitance and the inductance will attenuate higher frequencies more than lower frequencies causing a lower volume of high frequency content relative to low frequency content.
Other things that could also have an effect:
The length of the cables. Most of the above things I have talked about are on a per-unit-length basis, so the longer the cable the bigger these values. I am assuming you are using equal length cables if you are doing a comparison like this though.
The connectors. You also have capacitances and inductances in the connectors between the signal and ground that will depend on the distance between these two signals.
Shielding. Depending on how well the cables are shielded and how these shields are grounded could effect noise induced on the cables, but it didn't sound like this was what you were hearing.
Anyway, there aren't any real answers there for you. But that is what I know about wires that could be causing the differences you hear. As for what is causing the difference the best way I know to tell the difference is to figure out what the physical differences between the wires are either through obtaining drawings of the cables (if the manufacturers will give these out) or tearing them down yourself.
I remeber that in thermodynamics there is a formula to calculate the amount of heat an insulated cable dissipates and it had to do with the radius of the wire and the thickness of the insulation, the amazing part of it was that up until a certain point a thicker insulation helped the wire dissipate heat much more quickly than a thiner one but beyond said point the effect was the oposite.
I dont know how can it be related to this but there must be a relation, maybe on the volume? or headroom?
BTW im just sharing, making time till bongomania gets us that osciloscope readings.
I dont know how can it be related to this but there must be a relation, maybe on the volume? or headroom?
BTW im just sharing, making time till bongomania gets us that osciloscope readings.
There's a way to measure the effect of the cable on the response of a passive bass. Lift the ground at the bass and feed in the test signal from a spectrum analyzer at this point. Of course you have to shield the entire bass, or somehow get the pickups and controls into a shielded enclosure.
At what frequency will skin effect increase the resistance of an 18-gage center conductor to the point where it would matter in this application?
Also, AFAIK skin effect applies to the overall bundle, not to the individual strands. Otherwise, all RF cables would have stranded center conductors.
I'm an EE like you, and also like you, my specialties are in other areas, but I'm pretty sure that a lot of this stuff is more of an influence on much higher frequency signals. If you have an audio cable that is transparent to signals in the megahertz range, who cares?
And if you have three cables that are obviously NOT transparent in the audio spectrum, any curious and scientific-minded person would care.
I care enough to recommend measuring the electrical characteristics of the bass and cables.
Of course, but, no offense intended, we have not objectively established that such a thing has happened.
We've all seen how the "audiophile cable" threads go, so first, some ground rules:
--Keep it civil.
--Explain yourself, don't just blurt out a terse assertion.
--Nerd science welcome!!! No insulting or dismissing of science in this thread.
--Descriptions of tone and "what I/you heard" are understood to be only subjective.
Thanks.Now, on to the thread:
Here's an oddity that I've been stumped by recently. I have three different kinds of high quality (not expensive audiophile, but "semi-gourmet") instrument cables, and they all sound completely different. One of Elixir's new $70 extra-low-capacitance cables they sent around for review; a Fender "Premium Gold"; and several cables made of bulk Canare with G&H nickel plugs.
For a long time I've been in the camp that asserts that any non-faulty conductor, of similarly-conductive metals, will work the same as any other--and that claims of "better tone" by high-end cable companies are a crock. I use mostly the Canare/G&H cables because they are a solid, professional, and effective conductor with no BS, either from marketing or functionality standpoints.
Then I received one of those free tester cables from Elixir, and was frankly shocked by how different it sounds from my Canares. Sure the capacitance of a cable or plug can be manipulated to emphasize or de-emphasize certain frequencies, but considering I thought the Canares were pretty low-capacitance already, I did not expect this much dramatic difference. The Elixir passes an insane amount of high-frequency content by comparison, including extra hiss at the upper reaches of my hearing.
In the thread about the Elixirs, one guy posted that the Elixir seemed to lose some highs compared to his favorite cable, a Fender Pro Gold. So I had to buy one of those, to hear for myself. Well, on the one hand I totally disagree about the relative high frequency content, but OTOH the Fender sounds completely different, in its own way. Frankly it sounds really weird! Going back and forth between the Elixir and the Canare, it sounds like the same signal but with more or less highs. Going back and forth between either of those and the Fender, with the Fender it sounds like the entire spectrum of the signal is EQ'd in some exaggerated way. Hard to describe exactly.
Now, granting that all this listening is subjective and prone to placebo effect and other tricks of the mind, what am I actually hearing? Regardless of however the sounds may be interpreted and described, they are consistent as I go back and forth between the cables. IOW from one day to the next, I hear the same general type of results, to the same degree.
It seems impossible that what I'm hearing would result from just a difference in overall capacitance, since all three are supposedly so low in capacitance, and it's not like my hearing is so perfect that I could discern tiny variances like that. It also seems like a more complex filter would need to be made of obvious discreet components, not just wrapping the wire one way or another. Besides, pragmatists have long argued that the whole wire-wrapping geometry thing is a crock. But again I assert that I hear a dramatic, obvious difference between all three cable types.
So what's your take on this? Is it really possible to create a complex filter just by manipulating the wires and the specific conductive metals used in the cable or plugs? What is really going on here?
If you can REALLY think you can hear the difference between different cables (and I don't believe you or anyone else can), then maybe you should take Randi's challenge and prove you can and win $1,000,000.00 dollars:
http://www.randi.org/site/index.php/swift-blog/101-swift-october-19-2007.html
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