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Topic: A question about audio cables.  (Read 8258 times) previous topic - next topic
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A question about audio cables.

I recently had a discussion about the impact of audio cables on sound quality and their transparency. I’m no expert but I think that even a little logic dictates that cables obviously have no way of adding information to a signal other than distortion and that the sound quality through speakers cables for example doesn’t seem to be some big issue people have had for the last 70 years. Therefore, if anyone really does hear a difference with a cable, it could only be colouring the sound rather than being transparent. I really doubt of even that though. The counter argument has do with impedance and losing signal that creates roll off of frequencies over distances. The argument is also that things like lower impedance headphones could be even more succeptible to this. I feel that it’s a lot to ask, but could anyone explain if it’s even possible for speaker or headphone cables to make a difference and if so, does this actually happen in the real world?

Re: A question about audio cables.

Reply #1
Cables would have to be very, very long for capacitance to have audible interference with the signal. Impedance at such low frequencies can't affect frequency response of normal home speaker cables. AFAIK.
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Re: A question about audio cables.

Reply #2
The only thing I've ever experienced with cables (and it's happened on more than one occasion, with different cable and connector types) is that if there is a bad solder joint or a poor connector pin mating - as with oxidation - the volume will be reduced.  I've never heard a change in frequency response, added distortion, or anything else.  In fact, without knowing what was going on the last time this happened, I assumed it was a bad/dirty element on my balance pot since I could alter the levels and it would sound fine.

Another thing I've seen (but only once) is a high-end cable with a defective connector that also caused a volume loss.  To me this is a solid reason to build my own cables or at least choose pre-built units which have high reliability ratings over Monster and their ilk.  My cheap Radio Shack gold-plated cables have stood the test of time, most amusingly.

Re: A question about audio cables.

Reply #3
... could anyone explain if it’s even possible for speaker or headphone cables to make a difference and if so, does this actually happen in the real world?

It is certainly possible, but unlikely. If audible differences are experienced, it should be taken as a hint that something is amiss. It might be a case of poor contact, as Nichttaub has explained. It might also have to do with a grounding problem, or with RF interference. The causes may well be too obscure for a layman to understand, particularly in more complicated systems.

It is easy to come to the wrong conclusions in such matters. A systematic approach certainly helps, and some understanding of the technology is also useful. The claims you find associated with boutique cables are almost certainly wrong, however, and don't help understanding what's going on.

Re: A question about audio cables.

Reply #4
I recently had a discussion about the impact of audio cables on sound quality and their transparency. I’m no expert but I think that even a little logic dictates that cables obviously have no way of adding information to a signal other than distortion and that the sound quality through speakers cables for example doesn’t seem to be some big issue people have had for the last 70 years. Therefore, if anyone really does hear a difference with a cable, it could only be colouring the sound rather than being transparent. I really doubt of even that though. The counter argument has do with impedance and losing signal that creates roll off of frequencies over distances. The argument is also that things like lower impedance headphones could be even more succeptible to this. I feel that it’s a lot to ask, but could anyone explain if it’s even possible for speaker or headphone cables to make a difference and if so, does this actually happen in the real world?

The most common source of audible differences due to these issues comes from the cable acting as a significant series and/or parallel impedance, and the source and load doing similar things.

For example, most traditional SS audio power amps have a series inductor in their output circuits for stability and durability under dire conditions, that is outside loop feedback and it is usually sized to create an approximate 1/2 dB loss @ 20 kHz with a 4 or 8-ohm resistive load. Most speakers tend to also be inductive at high frequencies so some of this gets cancelled out in practical use.

Contemporary Switchmode power amps are generally worse with a few exceptional exceptions.  There are now such things as inductor-free switchmode amps, for example. There were always inductor-free class AB power amps.  Note that neither had much competitive advantage in the big picture.

A lot of PC audio interfaces have 50 ohm source impedances, and while this is pretty benign with practical audio cable loads. Put a pair of nominal 16 ohm headphones with a 2:1 or larger variation in impedance within the audible range and there may well be audible coloration. 

The largest sources of series impedance in speaker cables is inductance and series resistance. The series resistance is easy to overkill with reasonably thick commodity wire such as 12 or 14 gauge.  The inductance is easy to significantly mitigate by tightly twisting the wire, but again notice how infrequently this is actually done.  Must not be much of a practical advantage, eh?

Parallel impedance in speaker wire is generally a nit. Some attempts to maximize parallel capacitance in the interest of making a speaker cable with a low characteristic impedance in the same range as speakers has resulted in a certain number of dead amplifiers...


Re: A question about audio cables.

Reply #5
Thanks so much for taking the time to respond, I really appreciate it. So it sounds like problems can occur with the signal through various examples, but this is a problem that is often caused by issues like grounding / rf interference / speakers and headphones being mismatched with the soundcard or amp? Also that regardless, it’s a problem that has specific fixes like 16 gauge wire or twisting the wire, but that there are specific causes and remedies rather than purchasing more expensive audio cables to fix the issue? Would I be right then to assume that those laughable 700 dollar cables people speak of are just as vulnerable to these issues as others?

I’m going to have to read up a little to better understand some of these responses, especially Arnold’s. I went to school for audio engineering a decade ago, but most of the deeper stuff getting in to electronics I’m a bit lost with now but really want to relearn how amplifiers work. Also, I understand why class ab amps can be desireable for guitar, but why would audio amplifiers be class ab rather than class a?

Re: A question about audio cables.

Reply #6
Would I be right then to assume that those laughable 700 dollar cables people speak of are just as vulnerable to these issues as others?
Typically, yes. Sometimes even more so, as they use fairly radical constructions to "address" one alleged problem at the expense of others. For example, some cables are unshielded because they see the shield as a problem (for example regarding capacitance), which makes the cable more vulnerable to RF, which leaves RF immunity to the connected devices.

So be particularly cautious with manufacturers who seem to think that everybody else does it wrong and they are the only ones who understand the issues. The behavior of cables has been known for a long time, with very little chance of true innovation left.

Re: A question about audio cables.

Reply #7
Quote
Typically, yes. Sometimes even more so, as they use fairly radical constructions to "address" one alleged problem at the expense of others. For example, some cables are unshielded because they see the shield as a problem (for example regarding capacitance), which makes the cable more vulnerable to RF, which leaves RF immunity to the connected devices.

So be particularly cautious with manufacturers who seem to think that everybody else does it wrong and they are the only ones who understand the issues. The behavior of cables has been known for a long time, with very little chance of true innovation left.

That's what I figured because logically, a cable seems to be extremely simplistic, so if these problems could be remedied with a change of materials, why hasn't it already been done? I've seen cables that use silver and I guess if that had some kind of benefit, it could cost more but not 700 dollars. I actually do have experience with poorly shielded cables. I used to run my guitar in to my amp using an old coiled cable from the 60's because I thought that it looking cool would make me sound better hahah. Well, it turns out that those cables have awful shielding and also are much longer than they need to be, but that was a cable that definitely DID effect my sound. Drastically. I'd imagine its a whole different story with instruments then with stereo equipment too though?

Re: A question about audio cables.

Reply #8
I've seen cables that use silver and I guess if that had some kind of benefit, it could cost more but not 700 dollars.
Silver is a slightly better conductor than copper, but is vastly more expensive. The few percent of difference in conductivity can just as easily compensated for with a slightly higher cross-section of copper wire. But in most cases the conductivity matters little. So silver wire is a waste of precious resources for no real purpose.

Quote
... that was a cable that definitely DID effect my sound. Drastically. I'd imagine its a whole different story with instruments then with stereo equipment too though?
Yes, because the electrical conditions are very different. It is all about impedances, in other words it follows from rather basic electrical theory.

Instrument connections (i.e. a guitar pickup connected to an instrument amp) are quite high impedance connections, which means that the cable capacitance has a noticeable effect, and that interference is picked up easily. Impedances in home stereo connections are much lower, and in pro audio they are lower still. That reduces susceptibility to such effects.

Re: A question about audio cables.

Reply #9
Quote
Silver is a slightly better conductor than copper, but is vastly more expensive. The few percent of difference in conductivity can just as easily compensated for with a slightly higher cross-section of copper wire. But in most cases the conductivity matters little. So silver wire is a waste of precious resources for no real purpose.

I'd imagine that manufacturers are aware of the conductivity of copper and would take that in to account when designing cables. I also don't really get why a lot of the same people who claim more expensive wire will colour the sound less also use tube amplifiers to colour the sound, so the logic collapses pretty fast

That makes sense about higher impedance, probably why it's a bad idea for me to plug my guitar in to my stereo and use it as an amplifier too I'd imagine.

Re: A question about audio cables.

Reply #10
That makes sense about higher impedance, probably why it's a bad idea for me to plug my guitar in to my stereo and use it as an amplifier too I'd imagine.
It may work, sort of, but the odds are you're not going to like the performance. ;-)

A typical instrument amp has an input impedance of 1 MOhm. Hifi Stereo is more like 50 kOhm, or less. Sensitivity is also going to differ.

This is where standards come into play, which exist for home stereos, even though they're fairly loose. They specify nominal voltages and sensitivities, and also ranges of impedances, so that interconnect performance is not completely unpredictable.

Re: A question about audio cables.

Reply #11
That brings me to one more question than, if I may. Not sure if it's okay to really be breaking up the topic of this thread. I'm using an early 80's Hitachi amplifier to power some Bangs and Olfusen Speakers from the same time period. I've read online that they're particularly hard to match with the proper amplifier because they were made for B&O amplifiers. My Amp puts out 25 watts per channel and my speakers are apparently 50 watts RMS. So long as the amplifier isn't broken, shouldn't any SS amp from this time period be capable of driving any speaker without noticeable distortion or eq colouring so long as its providing adequate power at the volume level and isn't distorted from being turned up too loud? In short, is that just rubbish and should it not matter what amplifier is used for any set of speakers provided that it isn't broken?

Re: A question about audio cables.

Reply #12
So long as the amplifier isn't broken, shouldn't any SS amp from this time period be capable of driving any speaker without noticeable distortion or eq colouring so long as its providing adequate power at the volume level and isn't distorted from being turned up too loud?
I don't know about your particular case, but occasionally, one comes across amp/speaker combinations that really do need to be used with each other. Rather than power ratings, this may have to do with equalization, i.e. the amp may have a frequency response that compensates for an inverse frequency response of the speaker. I have come across such cases at the cheap end of AV receivers, but who knows, perhaps B&O did something similar.

I don't want to imply that such things are likely. You can't know for sure, however, until you've checked the details.

Re: A question about audio cables.

Reply #13
 don't know about your particular case, but occasionally, one comes across amp/speaker combinations that really do need to be used with each other. Rather than power ratings, this may have to do with equalization, i.e. the amp may have a frequency response that compensates for an inverse frequency response of the speaker. I have come across such cases at the cheap end of AV receivers, but who knows, perhaps B&O did something similar.

I don't want to imply that such things are likely. You can't know for sure, however, until you've checked the details.
More... Quote

Thanks! I didn't know if that was just total audiophile lies, or if there were some cases that it's true. Most of the time, probably not an issue though then it sounds like. They sound good to me, just a little too much treble and they could use a little more bass but I guess that's what an equalizer is for and maybe that's just how they sound regardless. Again like with the cables, I'd imagine even if sometimes speakers need specific amplifiers tailored for them, because of design oddities, those amplifiers that cost 1000's of dollars are complete and utter overkill for any system.

Re: A question about audio cables.

Reply #14
Would I be right then to assume that those laughable 700 dollar cables people speak of are just as vulnerable to these issues as others?
Typically, yes. Sometimes even more so, as they use fairly radical constructions to "address" one alleged problem at the expense of others. For example, some cables are unshielded because they see the shield as a problem (for example regarding capacitance), which makes the cable more vulnerable to RF, which leaves RF immunity to the connected devices.

So be particularly cautious with manufacturers who seem to think that everybody else does it wrong and they are the only ones who understand the issues. The behavior of cables has been known for a long time, with very little chance of true innovation left.
I suppose that backyard scientists always have a chance of making amazing discoveries, so it can't be ruled out that small companies could come up with something revolutionary but...

If any great breakthrough were to happen in the filed of conducting electricity along cables, where might we truly and realistically expect to see it: audio-boutique cable makers, or multinational manufacturers of all kinds of cable with huge resources and real r&d?

But the audiophile ego, especially in its communal form, insists that everything about processing and conducting "music" is difficult, and faces huge hurdles that only they, using expensive components, can overcome. The fact that musical signals are absolutely trivial compare to some other applications for which cables are made is anathema to them, and must be denied.

Some time ago, when I was trying to cure myself of audiophilia (still in recovery!) I found some very interesting stuff on Belden's site. Informative blogs by real engineers. I remember one guy saying that they make a cable for frequencies so high that the entire signal is carried in the skin, and the core is just there to give strength. He commented, in passing, that it would probably actually make a lousy audio cable!

The most important audio cables are the ones in the brain

Re: A question about audio cables.

Reply #15
Would I be right then to assume that those laughable 700 dollar cables people speak of are just as vulnerable to these issues as others?
Typically, yes. Sometimes even more so, as they use fairly radical constructions to "address" one alleged problem at the expense of others. For example, some cables are unshielded because they see the shield as a problem (for example regarding capacitance), which makes the cable more vulnerable to RF, which leaves RF immunity to the connected devices.

So be particularly cautious with manufacturers who seem to think that everybody else does it wrong and they are the only ones who understand the issues. The behavior of cables has been known for a long time, with very little chance of true innovation left.
I suppose that backyard scientists always have a chance of making amazing discoveries, so it can't be ruled out that small companies could come up with something revolutionary but...

If any great breakthrough were to happen in the filed of conducting electricity along cables, where might we truly and realistically expect to see it: audio-boutique cable makers, or multinational manufacturers of all kinds of cable with huge resources and real r&d?

But the audiophile ego, especially in its communal form, insists that everything about processing and conducting "music" is difficult, and faces huge hurdles that only they, using expensive components, can overcome. The fact that musical signals are absolutely trivial compare to some other applications for which cables are made is anathema to them, and must be denied.

Some time ago, when I was trying to cure myself of audiophilia (still in recovery!) I found some very interesting stuff on Belden's site. Informative blogs by real engineers. I remember one guy saying that they make a cable for frequencies so high that the entire signal is carried in the skin, and the core is just there to give strength. He commented, in passing, that it would probably actually make a lousy audio cable!



That's what one of my points was in the original conversation I had. I'd find it really hard to believe that some small boutique company has made some amazing discovery to some problem that doesn't even really seem to exist and in any other industry, the actual science behind it would've been leaked most probably instantly and even if all this were true, other larger manufacturers with more customers and bulk materials supplies would immediately make their own cheaper versions.

That's what I've come to notice too, that everything has to be this difficult journey to audio nirvana. Properly encoded mp3's in to a solid state amplifier driving speakers is too easy and inexpensive. You have to pour 1000's in to vinyl and get that to sound as good as possible, while using tube amps and exotic materials in cables. When I went to school for audio production and engineering, a lot of what I learned there even was blatantly wrong and it raised enough red flags for me to investigate. In a large part due to this site actually, I got over all that stuff pretty fast. Sometimes, there are still little remnants or the odd person making a compelling argument (always with no evidence though) that I still need to rectify.


Re: A question about audio cables.

Reply #16
Again like with the cables, I'd imagine even if sometimes speakers need specific amplifiers tailored for them, because of design oddities, those amplifiers that cost 1000's of dollars are complete and utter overkill for any system.
Well, in the case of the design oddities that I was referring to, they were actually there to save money for the manufacturer, even if it was only a dollar or so. So it happened at the opposite of the price spectrum, the cut throat end, where all tricks to save money are considered viable.

I found some very interesting stuff on Belden's site. Informative blogs by real engineers. I remember one guy saying that they make a cable for frequencies so high that the entire signal is carried in the skin, and the core is just there to give strength. He commented, in passing, that it would probably actually make a lousy audio cable!
That may well be true. The situation at frequencies beyond 1 GHz is so different from the audio range, that different constructions are called for, and different effects become dominant. There are some cases where cables do legitimately cost 4-figure sums. For example, when you do network analysis at such high frequencies, you need a cable that maintains close tolerances during a long period of time, despite being handled. All this while having minimal loss and minimal interference. That is hard to achieve, and requires meticulous attention to detail, and to manufacturing precision. Furthermore, the production volume is small. The resulting cable may easily be worth several thousand dollars. But that's OK, since the measurement instrument it connects to comes for a 5-figure or even 6-figure ticket.

Re: A question about audio cables.

Reply #17
Again like with the cables, I'd imagine even if sometimes speakers need specific amplifiers tailored for them, because of design oddities, those amplifiers that cost 1000's of dollars are complete and utter overkill for any system.
Well, in the case of the design oddities that I was referring to, they were actually there to save money for the manufacturer, even if it was only a dollar or so. So it happened at the opposite of the price spectrum, the cut throat end, where all tricks to save money are considered viable.

I found some very interesting stuff on Belden's site. Informative blogs by real engineers. I remember one guy saying that they make a cable for frequencies so high that the entire signal is carried in the skin, and the core is just there to give strength. He commented, in passing, that it would probably actually make a lousy audio cable!
That may well be true. The situation at frequencies beyond 1 GHz is so different from the audio range, that different constructions are called for, and different effects become dominant. There are some cases where cables do legitimately cost 4-figure sums. For example, when you do network analysis at such high frequencies, you need a cable that maintains close tolerances during a long period of time, despite being handled. All this while having minimal loss and minimal interference. That is hard to achieve, and requires meticulous attention to detail, and to manufacturing precision. Furthermore, the production volume is small. The resulting cable may easily be worth several thousand dollars. But that's OK, since the measurement instrument it connects to comes for a 5-figure or even 6-figure ticket.

Wouldn't even a data cable like a garden variety USB cable need to be orders of magnitude better than an audio cable?

Re: A question about audio cables.

Reply #18
I remember one guy saying that they make a cable for frequencies so high that the entire signal is carried in the skin, and the core is just there to give strength. He commented, in passing, that it would probably actually make a lousy audio cable!

This is not an esoteric cable - I have 100s of feet of it on my property in the form of trunk cables for the two cable systems that serve our area. It gets some maintenance. The workers are sloppy and leave scraps. The *cable* is silver plated aluminum tubng supported by an external steel cable.  This would be horrible stuff for regular audio. If it wasn't for skin effect it would be very lossy. Aluminum is only about 1/3 as conductive as copper, depending on alloying, annealing, and work hardening.

That brings up  the issue of a minor scandal in the world of commodity speaker cables. A fair amount of speaker cable is marked CCA or Copper Coated Aluminum. Some of it is marked as packaged, and some is not. It always looks coppery on the outside, but sometimes you can catch the glint of silver in it when it is cut.  12 gauge CCA is about as conductive as 16 gauge pure copper, which is not deadly, but is a lot less than naive purchasers may expect. The pur copper stuff is still sold for reasonble prices and readily available, but caevat emptor.


Re: A question about audio cables.

Reply #19
Wouldn't even a data cable like a garden variety USB cable need to be orders of magnitude better than an audio cable?
Depending on the definition of " better", yes.

A USB 2.0 cable (and even more so a USB 3.0 cable) needs to have well controlled transmission line properties. That's entirely unimportant for audio. It requires tight control over the mechanical properties and repeatability of the cable, i.e. dimensions and twist rates of conductor pairs. That needn't be expensive, particularly when production volume is high, but it requires a well controlled production process.

That's actually a problem for boutique cable vendors. Knitting together an audio cable is pretty simple, almost anything goes, including having it handwoven by naked virgins at full moon. Not so for USB cables. Which means that they have to use mass-produced cable and pimp it with expensive looking external ornamentation.

Re: A question about audio cables.

Reply #20
Cables can certainly seem to make a difference, even a significant one, if the test procedures are kind of sloppy (sighted, lack of precise level matching, etc).

Re: A question about audio cables.

Reply #21
I remember one guy saying that they make a cable for frequencies so high that the entire signal is carried in the skin, and the core is just there to give strength. He commented, in passing, that it would probably actually make a lousy audio cable!
I thought I learned in college that all electrons flowed on outer edge of the cable, or has something changed in the last 50 years?
Glass half full!

Re: A question about audio cables.

Reply #22
There's a specific depth to which the conduction occurs depending on the frequency of the signal.  At audio frequencies, it's large enough (a few mm) that most any reasonably sized wire will still be thinner than the skin depth.  At RF frequencies, it can become an issue and hence you'll see special stranded wire, various winding techniques, or different construction to address the issue.

On the subject of high-end cables for audio, I was recently following a forum thread elsewhere in which one poster "got it" and was highly skeptical of advantages from audiophile cables.  He got a response from another, obviously more gullible, poster who snidely replied that it was OK for others, but that he "liked to listen deeper into his music."  I barely refrained from responding that I couldn't listen that deeply or my head might get stuck where his obviously was.

Re: A question about audio cables.

Reply #23
There's a specific depth to which the conduction occurs depending on the frequency of the signal.  At audio frequencies, it's large enough (a few mm) that most any reasonably sized wire will still be thinner than the skin depth.  At RF frequencies, it can become an issue and hence you'll see special stranded wire, various winding techniques, or different construction to address the issue.
The skin depth that's usually quoted is actually the equivalent depth if the effect were abrupt. In reality it isn't, the current density gradually diminishes with distance from the surface.

At 1 GHz, the skin depth in copper is around 2 µm, so at such high frequencies, it really is a very thin layer that carries virtually all the current. Even the surface roughness becomes a significant factor at such frequencies.

Re: A question about audio cables.

Reply #24
I remember one guy saying that they make a cable for frequencies so high that the entire signal is carried in the skin, and the core is just there to give strength. He commented, in passing, that it would probably actually make a lousy audio cable!
I thought I learned in college that all electrons flowed on the outer edge of the cable, or has something changed in the last 50 years?

Current flow in wire is not based on electrons moving from end to end in time with the signal. The actual electrons sort of drift. The current flow is more like water flow in a hose that is already packed with water. Push one drop in at one end anyplace along the cross-section, and one drop of water has come out the other end someplace along the cross-section or something gets deformed.