I have earlier posted about Audio trends and snake oil. What annoyed then and still today in marketing and media that too often today then talking on hi-fi, science is replaced by bizarre belief structures and marketing fluff. It seems that there too many snake oil rubbish products marketed in the name of hifi. It is irritating to watch the stupid people in the world be fooled with things like exotic materials, directional cables, thousand dollar IEC power cables, and all that rubbish. “If you pay ridiculous money for these cable you will hear a difference, but don’t expect your friends to”
I can agree that in analogue interconnect cables there are few cases where better cables can result in cleaner sound. And there are very many cases where there is no objectively noticeable difference.
In digital interconnect cables story is different than on those analogue interconnect cables. Generally in digital interconnect cables the communication either works, does not work or sometimes work unreliably. The digital cable either gets the bits to the other end or not, it does not magically alter the sound that goes through the cable.
But this digital interconnect cables characteristics has not stopped hifi marketers to make very expensive cable products that are marketed with unbelievable claims. Ethernet has come to audio world, so there are hifi audiophile Ethernet cables that do not make sense to me. With Ethernet the data either gets through the cable without any changes to it, or it does not get through at all. Ethernet has checksum on every data packets to detect for any errors (which are rare) in the transmission and all the packets that have data changed in any any way are discarded. So Ethernet cable can not not magically slightly alter the digital sound that goes through the cable.
Here are links to two articles on such expensive audiophile Ethernet cables:
Is streaming cable more or less expensive than $1000 audiophile snake-oil ethernet cable ?
https://audiobacon.net/2019/11/02/the-jcat-signature-lan-a-1000-ethernet-cable/
Gallery: We tear apart a $340 audiophile Ethernet cable and look inside
https://arstechnica.com/gadgets/2015/07/gallery-we-tear-apart-a-340-audiophile-ethernet-cable-and-look-inside/
Apart from the absurdly high price tag and more mechanically robust connectors, I see nothing special on those cables for carrying the data signal. I suppose those does look quite attractive to some users and this makes them willing to pay the high price.
Despite the fact that some people desperately want there to be audiophile Ethernet cables, there simply is no such thing. The IEEE standards do not include a superset of specifications that make a regular Cat-7 cable into an “audiophile” Cat-7 cable. If you still believe those “audiophile Ethernet” cables sounding better, please inform yourself how an Ethernet and Ethernet cable works.
179 Comments
Tomi Engdahl says:
Just… beyond me. I’m a double Cisco CCIE and a master of electronics…
https://www.alpha-audio.net/background/the-absolute-and-ultimate-guide-to-streaming-audio-network-optimization/?fbclid=IwZXh0bgNhZW0CMTEAAR1k8YdPlF_tgkIpTH_Mv7E6ypaEHg1Fh5ceu9PT2vtmKnCAY82mq6f_eIg_aem_2XBuMPPjpQyT9UaRHBr-sg#comment-28482
Tomi Engdahl says:
They at least kinda built something.
There are worse examples like an ethernet filter that snaps on the end of an ethernet cable.
This guy is insulting to his own oscilloscopes.
https://youtu.be/c6lZFN-LW-U?si=qYpcIuJuvtCNbKsW
Tomi Engdahl says:
https://www.furutech.com/2024/11/27/24563/
Directional Ethernet cable for optimal sound!?!?!?!?
“Important caution for cable direction:
* This LAN Cables is directional for optimal sound reproduction. The cable will not be damaged or damage equipment if connected in the wrong direction, but audio signal will not be optimal. The direction marked by the arrow is the input (source) side. Check the arrow markings on the connector before connecting.”
Tomi Engdahl says:
Ethernet data signal is already galvanically isolated on both devices with transformers. When using shielded Ethernet cable the shield will make a direct connection that can sometimes lead to ground loop problems that can be solved by using signal isolator or unshielded Ethernet cable.
Tomi Engdahl says:
Let the laws of physics guide you, not the myths and snakeoil of audiophoolery.
Tomi Engdahl says:
Audiophiles Keep Failing the Test That Should End the Amplifier Debate
https://www.headphonesty.com/2025/03/audiophiles-keep-failing-test-end-amplifier-debate/
Why do expensive amps keep selling even when blind tests prove they sound the same?
Dropping $2000 on a premium amplifier feels like it should transform your sound. Yet, when researchers test listeners under controlled conditions, most can’t identify which amp is which.
Tomi Engdahl says:
https://www.headphonesty.com/2025/05/songs-expose-headphones-midrange-problems/
Tomi Engdahl says:
I’m almost impressed. There’s Just enough smattering of accurate terms and facts to make this cable look good but all they actually said is “our cable gives better audio then a shit-tier eBay cable that has the kind of wiring faults you can pick up with a Fluke tester”
This is technically correct. If you have a faulty cable with loose connections that’s causing packet loss that is likely to affect sound quality in the form of stuttering due to packet retries
But a £3 ethernet cable from your local office supplies shop will also do everything this thing does.
Tomi Engdahl says:
Misinformation or Simple Test? – CAT5e vs CAT6a
https://m.youtube.com/watch?v=ygspiLW-HQ0
Passion and anger tend to be inversely proportional to knowledge and understanding
Tomi Engdahl says:
HiFiPig.com Network Purifier review
https://www.russandrews.com/eu/hifipigcom-network-purifier-review/
Like many, despite having heard the differences our products can make over the years – her most recent experience being the review of our RF Router back in August, which you can read here – Janine Elliot admits to being a natural sceptic when it comes to accessories. The results of testing the Network Purifier came as somewhat of a surprise then…
Before getting into the nitty-gritty of the review, Janine precedes her testing with a brief background to the development of the MiniZap technology, how they were first developed for us by Ben Duncan, based on a Zobel network, and how that tech has been adapted over the years to a range of noise-reducing products adapted to a variety of applications. Janine notes that the product under review here utilises “no less than eight MiniZap filters”.
Tomi Engdahl says:
https://www.reddit.com/r/BudgetAudiophile/comments/1b8rdk9/is_audiophilia_all_bullst_is_it_mostly_bullst/
After a number of years, I’ve come to the conclusion that it’s mostly bull.
Speakers matter.
Subs make smaller speakers sound better.
Room acoustics matter.
PEQ isn’t intuitive, but it’s incredibly powerful.
Amps and DACs are solved problems. Any decent electronics will do the job.
I’ll not even start on cables or ethernet switches.
Audiophilia, subjective or objective, is mostly unlearning to enjoy stuff that previously brought joy. It’s better to just love music.
Most of the subjective opinions are worthless and a lot of supposedly high end products deliver no gains over budget ones.
It’s a great time to be an objective audiophile, focused on the right things and getting great results for a reasonable cost.
I have virtually given up HiFi as a hobby as there is SO much BS. It gets to the point where I feel my intelligence is being insulted!
I assume its like wine. There are $100 bottles that are noticeably better than most $15 bottles. That said there are a few amazing steals in the $15 range. And the best $100 wines are maybe more tasty, but they aren’t 5x more tasty.
Well, it’s a hobby, and as with most hobbies, a lot of “audiophilia” is the desire to get new gear and justify it. I am myself pondering at the moment, if I should get a nice, hi end vintage amp to replace my Aiyima T9 although it might not sound any better.
Most bullshitty audiophile concepts I’ve heard however:
“Clean” electricity
Super heavy and acoustically dead audio racks – because apparently they “hear” other ones.
Hi end, audiophile cables – measuring tests have showed no advantage to regular, decent copper cable.
Maybe I just don’t have the hearing ability of a bat and it’s all true, lol.
Decades back when I knew less than nothing, I had occasion to A/B test in a listening room between my second hand £50 NAD CD player and a £12,000 Linn CD12.
I couldn’t tell the difference, even with my near perfect hearing at the time.
Anecdotes are not data, but I have always struggled to really evaluate any digital source unless it had something super obviously wrong in terms of mechanical issues or lossy codecs.
I bought my first CD player circa 1988. The Good Guys store had a display of probably 75 players. NAD was likely the most expensive and Magnavox the cheapest. I brought some good Sennheiser headphones and listened to all the models with headphone jacks. That narrowed it down to about 10 IIRC. There was one that sounded like crap, and all the others sounded identical in every way. I ended up buying a Pioneer because it had the multidisc options I wanted.
This points at the complete answer: the real BS is that most “audiophiles” is that they refuse to blind A/B test their gear. If you’re not willing to do that, you don’t actually care about audio quality, you care about fancy gear.
My 2 cents:
Penny 1: Folk who are deep into it use music to listen to their system, rather than use their system to listen to music.
Penny 2: Almost nobody has a clean enough listening environment to discern the differences they claim to hear. HVAC, the fridge, traffic, the leaf blower next door, wind, etc. etc. Any of these will mask the 1% difference between one item and another.
Drop the needle, turn it up, enjoy.
I think the real deep ‘audiophiles’ are robbing themselves of the pure enjoyment of listing to music. 95% of systems are more than good enough. Sure, upgrade to better speakers / bigger amp – cool. Have an electrician run a separate power circuit on silver cables for ‘cleaner power’? Fuck off.
After 40 years in the speaker business here are my opinions on the relative importance of system components:
Quality of source material
Speakers and placement thereof
Room environment
Sufficient amplification
Stuff in the middle does sound different. Different doesn’t mean better or worse, many times just different.
There is no free lunch. A component thats’ primary design criteria is to be as cheap to build as possible is not going to perform as well as one built like, and weighs as much as a high end german sedan.
Finally few things can offer as much fun for so little money as vintage and budget audio. Enjoy the finding, fixing fiddling with the hardware and be transported by the music!
Top 1% Poster
Speakers matter.
Subs make smaller speakers sound better.
Room acoustics matter.
PEQ isn’t intuitive, but it’s incredibly powerful.
Amps and DACs are solved problems. Any decent electronics will do the job.
I’ll not even start on cables or ethernet switches.
Yea, hate to break it to you but those are the typical arguments of an objective audiophile. You should throw in some links to ASR measurements and Harman research for a full picture.
Tomi Engdahl says:
Audio Bullshit.
https://medium.com/@PanoramicAudio/audio-bullshit-49e176cf9a28
“You take the blue pill – the story ends, you wake up in your studio and believe whatever you want to believe. You take the red pill – you stay in Wonderland and I show you how deep the rabbit hole goes.”
If it sounds too good to be true, then it probably won’t sound too good.
There’s a whole world of bullshit out there, ready to try and suck you in. Some of it’s harmless, such as the idea that you can improve room sound using egg crates (which do not obtain the density and fibrous nature required to convert high frequency waves into heat energy, thus reducing reflections), but when bullshit creeps into advertising, it’s usually there to mislead you and lighten your wallet.
If you want to progress quickly as an engineer, be objective with how you approach any scientific claims regarding your potential purchases. These are the tools you’ll be using to create your art, so choose wisely and be aware that such tools are only useful if you know how to use them. Try new techniques and improving your aural abilities before you commit to spending money to improve your sound, and vigorously assess the bias and logic behind marketing campaigns. Remember that companies exploit your lack of confidence to sell to you, and in educating yourself and gaining more experience, you’ll be far harder to manipulate into making poor judgements.
Tomi Engdahl says:
I propose that, if all the “last few percentages of improvements” promised by this and that utterly idiotic product, it’s possible to achieve some 9,000 % fidelity with respect to the source material.
What a time to be alive!
Tomi Engdahl says:
If it doesn’t run the audio through mercury filled filter tubes, I’m not interested. I feel that, if audiophiles can have ridiculous, baseless standard, I can have outright dumb and impossible standards.
Tomi Engdahl says:
I do not know how many people think that streaming is some kind of glorious “continuous data stream from the service to the endpoint with perfectly synchronized clock”. When I read this bs, I just can’t stand that. This kind of stuff mostly comes up in the discussions Ethernet vs Wifi.
Nobody actually realizes that it’s all packet based transmission with error correction and de-jitter buffer at the receiving end. And the biggest audiophools get stunned when you tell them that packets arrived to the endpoint most likely used different paths on the network…
Tomi Engdahl says:
“Omnilan – We shape the zeros and ones for your system”
Dusán Roczkó no, no, they insert carefully blended 0.5s in there to smooth the harsh transitions between 0 and 1….
Tomi Engdahl says:
Ooh I just had an idea. Start an “audiophile” ISP claiming you use this kind of networking equipment and charge them $300/month
Tomi Engdahl says:
I don’t have the foggiest idea why these audiophools don’t realize that their brain tricks them into hearing things.
I mean, just for how long can you succumb to your confirmation bias?
I guess they really have no clue what sound is, how it stored, how it is reproduced. It is pitiful, really. They spend thousands and thousands, and in the end have the very same sound as before.
Tomi Engdahl says:
Ethernet is a digital system, 0s and 1s, Trues or Falses. Nothing in between. If the cable is rubbish then external devices could cause interference, error correction will try and sort it and then if that doesn’t work it fails, pretty much completely. Range is governed by cable and drive and receive electronics, but once it ‘works’ incremental improvements in cable performance make zero difference, its still 0s and 1s.
I am surprised audiophools haven’t jumped on the fibre optic bandwagon as that is my ‘goto’ in difficult industrial environments where distance and/or external electrical noise create problems for control systems. Single mode fibre, suitable for multi km transmission dressed up as audiphoolery for a link of a few feet anyone.
Tomi Engdahl says:
These very thick hifi Ethernet cables put a huge mechanical stress on the sockets, stupid idea .
Tomi Engdahl says:
Well, it is a physical impossibility that CAT cable for Ethernet can have any impact on the audio output and quality, leave alone magic DSP-like capabilities.
The poor schmuck just has bad ears, and an overpowering imagination, that’s all.
Michael Eickemeier Well, not impossible. It could be flooding the inside of a crappy DAC with high energy RF, that the DAC then detects and adds to the analog waveform.
Or, it might not.
Steve Louton you’re talking about random changes to the bit values, that would destroy the content totally. High energy RF cannot act like a DSP, and change the bytes in an orderly fashion, that alters the sound quality in any certain and predictable way.
The RF energy could infiltrate the analog side, and be heard as data noise, but that’s about it.
Let’s not forget that Ethernet uses packets, which are not transmitted synchronously. Some traffic can interfere, so packets can arrive at completely different times, or get lost and re-transmitted, then assembled back, buffered and stored, then fed to a DAC, re-timed and converted.
It is impossible that an Ethernet cable can change the sound quality.
Michael Eickemeier Yes, I was strictly referring to RF conducted emissions entering the circuitry that could be detected (i.e., signal detection) and corrupt the output analog signal. We test this in avionics suites all the time. I agree the data path acts just like you describe; you certainly wouldn’t affect tonality that way.
Now whether you actually get enough RF into a system to corrupt the analog signal … I wouldn’t suspect you would, but if there is, it should certainly be measurable.
Steve Louton measurable, and audible. It’s data noise. Heard it too many times, unfortunately.
Data noise doesn’t make the sound different, as in smoother, or harsher or whatever. It’s just noise on top of the otherwise unaltered audio signal.
Audiophools never refer to data noise, they say that the cable changes the quality of the audio in some specific way, alas, it cannot change it.
https://www.facebook.com/share/p/1CVHDipNgk/
In case you’re wondering, all of this detail, nuance and sonic improvement, comes from an Ethernet cable.
No doubt it just sounds ok or even bad until you burn it in for 300 hours. Be patient.
And all this time dumb old me thought that a properly made certified and tested cat 6a from Belden for $20 shipped was good enough to get the 1’s and 0’s to the DAC.
Tomi Engdahl says:
Adds analogue-like sound to digital Ethernet audio
“The standard Orange Lan Jitters aim to refine your music listening with a natural, analogue-like sound and a range of sonic improvements, thanks to QSA’s proprietary techniques. Designed to provide a deeper, more immersive audio experience over time, they cater to those seeking relaxation or an enhanced music journey, offering clearer, more detailed, and natural sound across all listening levels..”
https://www.futureshop.co.uk/quantum-science-audio-lan-jitter-orange-pair/
Tomi Engdahl says:
Google “how to test non linear effect of audio interconnect cable”
To test an audio interconnect cable for nonlinear effects, use a comb-filter method with specialized equipment to measure harmonic distortion. A basic method involves using a signal generator to send a tone through the cable to an analyzer, which measures the output for added harmonics not present in the original signal. The goal is to identify frequencies created by the cable itself, which are a sign of non-linearity.
Method Using a Comb-Filter
1. Use specialized equipment:
This method requires a signal generator and a frequency analyzer, possibly a double comb-filter system for improved accuracy.
2. Generate test signals:
The generator sends a specific signal, such as a pure tone or a comb-filter signal, through the audio cable under test.
3. Analyze the output:
The analyzer measures the signal coming out of the cable.
4. Identify distortion:
The presence of frequencies not in the original test signal, particularly harmonics of the fundamental tone, indicates non-linear distortion caused by the cable.
Key Concepts
Non-linear distortion:
This occurs when a cable introduces frequencies to the audio signal that were not present in the source, altering the signal’s shape.
Harmonic distortion:
A common type of non-linear distortion where new frequency components, called harmonics, are created at multiples of the original signal’s frequency.
Total harmonic distortion (THD):
A specification that quantifies the total amount of harmonic distortion produced by an analog device, or in this case, a cable.
Comb-filter:
A signal processing technique that can create a series of regularly spaced frequencies to reveal subtle distortions in a signal.
Why Basic Tests Are Not Sufficient
Continuity tests:
A simple continuity test with a multimeter only checks for basic electrical faults, like breaks or shorts, not non-linear effects.
Noise readings:
While noise is a form of unwanted interference, it’s different from the distortion introduced by a cable’s non-linear characteristics.
Subjective listening:
While useful, listening tests can be unreliable and are difficult to use for specific measurements of cable distortion
Tomi Engdahl says:
“Improve your listening experience” could be anything including the color of the cable insulation or a fondness for firehose-sized cables.
When “high-end” cables are compared to more “ordinary” cables using professional test gear or by properly done double blind tests, no differences can be discerned*. One test was run against a length of barbed-wire fencing; again, nobody could tell the difference.
*Not even by “audiophiles” who, when they knew what cables they were listening to were effusive in their claims of “amazing differences”. Confirmation bias strikes again.
https://www.quora.com/Whats-the-best-way-to-test-if-high-end-audio-cables-actually-improve-your-listening-experience
Do high end audiophile cables live up to the hype?
I dont know about super expesive high end. However, we went to an audio store and my friend purchased a $500 cd player back in the 90s. While test listening to it the salesman mentioned some like to buy better rca cables. He turned power off and removed the cheapie cables all components and connected some $45 rca cables..we played the same tracks and their was an audible improvement. All 3 of us agreed the midrange and lower frequencies sounded fuller. He then did the same with $400 pair of cables..we heard just a slight improvement. My friend bought the $45 cables and never looked back.
Fast forward a few years and i made a purchase of a denon cd player. Sounded fine..then one day i figured i would pick up better rca cables..think i paid $35. The next time i played red hot chili peppers i was dumbstruck. Many of there songs have horns recorded in them and i never heard them before. So might be worth it to spend a little money on better cables. Not huge investment cables in my opinion.
Tomi Engdahl says:
https://community.element14.com/technologies/test-and-measurement/b/blog/posts/building-and-testing-audio-cables
What is wrong with Off-The-Shelf?
The cable I inspected did not have great shielding (proven through tests – see later) consisting of wire strands providing perhaps 30% (this is a guess) of coverage of the centre conductor.
In its favour, the cable outer insulation was very thick and maybe could withstand rough handling as long as the rough handling was no-where near the connectors.
Furthermore it was a very low cost cable and probably would be adequate in a non-electrically-noisy environment. The connections would probably be fine if the cable was not mishandled.
What things would we want to see in good audio cable assemblies?
Everyone will have different requirements but from a general point of view these requirements would come out pretty high:
100% coverage shielded cables, grounded, to minimise capacitive pickup and RF pickup
Two and three cores for flexibility. The two-cored cable could be used for mono or stereo applications; for mono use one of the cores would provide the audio signal and the other core would be used for the ground connection. The shield would be grounded at one end. For stereo use, the three core cable could be used, and the shield would be used as the ground connection at one end. For balanced audio use (e.g. with XLR connectors) then again either cable could be used.
Ideally a controlled pair cable for balanced audio applications, to reduce the effects of as many modes of noise pickup as possible
To provide protection from interference at low frequencies the best practice is to have the shield connected only at one end. When we hear mobile phone pickup on audio circuits, this is actually low frequency interference components that we are hearing. However we also want to minimise high frequency pickup up to about a few MHz just in case it mixes with signals in electronics. There is a ‘hybrid grounding scheme’ discussed in an Analog Devices paper (PDF) where one end has a capacitor to ground. Any ceramic 100nF capacitor would work admirably. A large ferrite may be slightly effective too but unlikely; the input impedance of audio circuits is far higher than the impedance from the ferrite and we might obtain less than a dB of benefit at best, and at audio frequencies there would be no benefit, it would just be a weight on the end of the cable. But worth experimenting with if there are issues caused by high frequency (of the order of MHz or higher) signals.
For connectors the following properties would be good to see:
Ruggedness
Fully shielded
Easy to solder terminals
Conductors secured with more than just solder
A cable clamp
Strain relief
Building Audio Cable Assemblies
Engineering practice dictates that solder alone should not secure a connection, wire breaks should not short against other pins, the cable should be clamped and cable strain relief should be provided to allow the cable to flex without strain near a connector. One particular difficulty is holding the connector and wire together while soldering. Some websites incorrectly state that it is ok to add solder to the connector and wire separately and then re-melt solder on the connector and then add the wire while the solder is molten in an attempt to make it easier to form the join.
A clamp can solve the problem. Any clamp with soft inserts (e.g. pieces of wood) could be used. The one below is all aluminium and has a V-shaped groove so the part doesn’t move too much.
Summary and Next Steps
A lot of topics were quickly covered in this post; cable requirements, connector requirements, how to assemble good audio cables and how to test them. It can be seen that it is entirely practical to hand-assemble audio cables that will out-perform many commercial ones, and confirm their behaviour with low-cost test tools. It was very impressive to see such outstanding results from the radio receiver method using the model 9533 and 9841NH cables that were tested.
After having tried these simple tests it was interesting to find an IPC Test Method (PDF) which uses a fairly similar method of checking cable shielding. It too uses a source cable with a test signal, this time from an RF signal generator. The cable under test is mounted parallel to the test signal cable at a fixed distance. The received signal is measured with a field intensity meter. With more time or if I was checking many cables it would be worthwhile building up such a dedicated test rig. I may try to run similar tests on other types of cables, for non-audio applications.
You’re right, the 9841 is fairly stiff, so this could limit its use. Also it is an interesting point, how to improve for the unbalanced audio scenario. There is an article here that too mentions the ineffectiveness of aluminium foil shields for inductively coupled noise Field Wiring and Noise Considerations for Analog Signals – National Instruments. (About two-third down through the article). I’d considered running the test by building a transformer out of the two wires, i.e. the signal source and the cable under test, in order to see if the braid is more effective than the foil for the low frequencies. The same speaker method could be used to check for the tone or measure it with an op-amp circuit. But the wires are thick so maybe it would have to be an air core, maybe spirals wound on top of each other around a cardboard poster tube, just taped into a large coil shape basically. I’ll try to think of further refinements rather than the current few twists of coupling, since this result will be important for the unbalanced signal scenario.
The Neutrik clamping is definitely elegant – and it is possible to prevent the cable spinning while screwing in the plastic cap by holding from the connector interface rather than the barrel, so this is neat too.
https://www.ni.com/en/shop/data-acquisition/measurement-fundamentals/field-wiring-and-noise-considerations-for-analog-signals.html
Tomi Engdahl says:
Radio Frequency (RF) Analysis of Speaker Cables/Reflections
https://www.audiosciencereview.com/forum/index.php?threads/radio-frequency-rf-analysis-of-speaker-cables-reflections.7154/
This is an article our technical member @DonH56 kindly wrote on another forum and place. I am copying it here given the recent interest in its content:
Apples vs. oranges, anybody? In this thread we’ll take a look at speaker cables from an RF perspective, not something usually discussed. Although closer to my professional life than the usual audio analysis, I would not have thought of this except for the prodding by (“interaction with” if you prefer) a fellow engineer. I would have said transmission line effects at audio frequencies are negligible. Was I wrong? Well, the jury is still out, but it makes for an interesting thread, so here we go!
Recall that wires have impedance terms (resistance, inductance, capacitance, conductance – RLCG) distributed along their length. They reduce the cable’s bandwidth, reduce the effective damping factor at the speaker terminals, and add distortion (though the cable’s nonlinearity at audio is insignificant – I am not covering that now). Also remember that it takes time to get from one end of the wire to the other, even for an ideal line. Finally, you may recall from the DAC Reflections thread that mismatches among the source (amplifier), line (speaker cable), and load (speaker) impedances cause reflections. That is, not all the energy goes straight into the load as we would hope, but some gets reflected back. The bigger the mismatch, the bigger the reflection, the less signal is initially delivered to the load, and the longer it takes to settle to its final value.
Note vp is for the electrical signal, not the sound waves out of the speaker! Sound travels around 1130 feet/s, while the signal in the wires typically travels about 1/2 the speed of light (1/2 of 186 thousand miles/s) for an audio cable (can be 0.9c or more for RF cables). The good news is I am not going to use these equations any more, but they are the basis of the pictures that follow. For more info, look up transmission lines on Wikipedia or your favorite RF handbook.
Now let’s look at a simple circuit formed by an ideal amplifier (a perfect voltage source), a short (20-foot) speaker cable, and ideal 8-ohm resistor to model the speaker. For speaker cables I used an ideal and lossy 8-ohm cable, and ideal and lossy 93-ohm cable that is essentially the original Monster Cable. The delay time is ~45 ns for these cables. I applied a step input with a 10 ns edge (8 ns rise time, equivalent to ~44 MHz bandwidth). The results for several test cases are shown in Figure 2, with the output voltages measured at the load.
Now, with an 8-ohm cable and 8-ohm load the match is perfect so no reflections occur (gamma = 0). It is difficult to see but the ideal 8-ohm cable rises smoothly in 8 ns and starting 45 ns after the input step as expected. The lossy 8-ohm cable is nearly the same, but with one tiny little perturbation at the top (barely visible in the green line) and rise time is 8.05 ns. I cannot imagine anyone would hear any impact from either 8-ohm cable.
The 93-ohm case is much more interesting. Now we see mismatches causing reflections and the resulting longer settling time. Because of the mismatch between line (93 ohms) and load (8 ohms), only part (about 16 %) of the initial energy is absorbed, and the rest is reflected (“bounced”) back to the amp. There it is again reflected (100% since the amp is ideal), and travels back to the load (speaker), adding a bit more power but again reflecting most of the energy back. We see the signal at the speaker building in steps throughout this process. This back and forth goes on for several microseconds as seen in the picture, with the voltage at the speaker gradually rising as a little more energy is passed on to the load at each “bounce”. The effective rise time is now about 1.2 us (~300 kHz bandwidth) – still well above the audible band, but much lower than the ideally-matched case. Again, the difference in rise time between the ideal 93-ohm line (1.16 us) and lossy line (1.18 us) is insignificant.
Let’s talk just a bit about this bouncing that is going on… Some of us are old enough to remember those hard rubber “Superballs”, and the rest have hopefully seen how a small plastic ball bounces. I am going to use that for an analogy (and yes, I know this is not terribly rigorous, please bear with me). The ball is the signal, and the ground the load. What we’d like is for the load (ground) to instantly absorb all of the ball’s (signal) energy, giving nothing back. This would be like throwing the ball into a pool of thick, gooey mud. One splat, and that’s it. The other extreme would be smooth concrete. The ball hits and bounces, bounces nearly as high the second time, and bounces many times before all its energy is gone. Only a little is transferred to the concrete with each contact. In between is something like grass; a few bounces and we’re done. Perfect energy transfer would be like mud, with a reflection coefficient of 0, and concrete is a coefficient of almost 1 with almost no energy transferred.
The question of whether the mismatch matters is an interesting one. I think it is safe to say that a 45 ns reflection is unlikely to be heard by anyone. Our ears should average those little steps so we don’t hear them (I think). As for the effective change in rise time, a 20 kHz sine wave has a rise time of 17.5 us, about an order of magnitude slower than the cable. So, the 93-ohm cable would have to be ten times longer (200 feet) to approach the rise time of a 20 kHz signal. Or, have an impedance ten times higher, i.e. a cable with very low capacitance and/or very high inductance. There may be such cables; I do not know. From a rise time, or bandwidth, perspective the cable does not seem to matter.
The other argument that has been made is how the reflections impact our perception of location. It was shown in a much earlier thread (not one of mine, though I did run some numbers) that we can actually perceive timing changes in the microsecond region. This is based upon our ability to recognize a small shift in location which, when calculated as a time difference between our two ears, works out to just a couple of microseconds. So, might a relative time shift of 1 – 2 us caused by reflections be noticed? The problem with this theory is that, treated as a time constant, again there is an order of magnitude between the cable’s time constant and that of a 20 kHz signal. The audio signal, especially when comprised of many different tones (like music), may well mask the effect. And, the reflections operate upon all signals, meaning all edges are delayed. Finally, if the mismatch is the same for each speaker, the same signal will have the same equivalent time delay for each speaker. Of course, different frequencies will see different impedances in real speakers, thus the reflections will be different for different frequencies. This could cause the image to shift (vary) with frequency. Clearly it can get complicated… What is also clear is that transmission line effects can matter in speaker cables, though whether these effects are audible I can’t say.
One last look at this fairly ideal case: what if a more realistic (slower) rise time is used? A 10 us edge (8 us rise time, a little over 40 kHz) is shown in Figure 3. The reflection “stair steps” are no longer visible and the rise time is essentially the same as the source (8 us) for the 8-ohm and 93-ohm traces. The delay caused by the distributed RLC of the 93-ohm line is visible, however. The 8-ohm lines’ delay is about 45 ns, as expected from T calculated above, but the 93-ohm lines’ delay is about 0.5 us. An ideally-matched line and load renders the LC essentially “invisible”, but a mismatch means the distributed impedance is “visible” and impacts the propagation delay consistent with the effective bandwidth. Again, the audibility is a matter of some debate…
Where can we find an 8-ohm speaker cable? Or do we have to make such cables ourselves?
I find it funny that many audiophiles are so obsessed with speaker cables and willing to pay big money for designs with dubious constructions, but none of them seems to have tried to find out if speaker cables with proper impedance values would make a difference in a DBLT.
Why? Generally speakers don’t present 8 ohm resistive loads, at the frequencies where impedance matching has any relevance they can be tens or hundreds of ohms depending on the crossover design. Through the audio range they can vary from low single digits to more than a hundred ohms.
This thread is because of this thread/train wreck
When you want to experiment, just for the fun of it, and don’t want to spend a fortune on expensive cables or paralleling coax cables you may want to try this:
Cat5 cable is 100 Ohm per pair. 4 pairs in 1 cable. so you can make a 25 Ohm cable with one cable and thus need 3 of those cables in parallel.
This will get you close to 8 Ohm with a very low investment.
You need to tie all white stripe wires together and all colored ones together.
Then try to blind test it against other cables or other some very expensive high capacity cables.
The peddler in question suggests Zobels to make the impedance match worse and increase the “need” for what he’s selling.
Actually, already been there, done that, when years ago braiding multiple Cat5 cables into one DIY speaker cable was the fad. I don’t recall hearing something clearly “superior.” Maybe it was because I used four cables instead of 3, so the impedance was only 6.25 ohms so it was not a good match with the 8-ohm speakers
(this is a joke obviously, as speaker impedance could vary wildly).
I must be missing something! Why would anyone care about the Radio Frequency Transmission Line Characteristics in a Low Passed audio signal cable? Cables behave much differently well above 100kHz than they do at audio frequencies.
Don’t fall into the trap that snake-oil marketing departments use. That of taking engineering knowledge way out of context and then misapplying it.
Tomi Engdahl says:
Technical Article: Does Audio Cable Skin Effect Matter
https://www.audiosciencereview.com/forum/index.php?threads/technical-article-does-audio-cable-skin-effect-matter.7157/
Alternating current carriers in a conductor tend to travel near the surface. This happens due to opposing eddy currents from the magnetic field generated whenever alternating current (a.c.) flow is present. These are not generated by direct (d.c.) flow since current flow is all in the same direction and thus opposing eddy currents are not created. The effect is frequency-dependent, resulting in carriers traveling closer to the surface at higher frequencies. Because less cross-sectional conductor area is used as frequency increases, the effective resistance rises as frequency increases. Note that at d.c. (0 Hz) the entire cross-sectional area of the conductor is utilized.
Skin depth (sd) is the depth at which current density has fallen to about 1/3 (actually, 1/e, or about 0.37x) the density at the surface. The definition arises from EM equations beyond the scope of this article. A related term is the penetration depth (T), the depth by which virtually all current in the conductor flows. If the depth is greater than the conductor’s depth, then the conductor’s entire cross-sectional area will be used and d.c. and a.c. resistance will be essentially the same. At higher frequencies, only part of the conductor’s depth may be used, and effective (a.c.) resistance increases.
Figure 1 shows both parameters (skin depth and penetration depth) over frequency, from 10 Hz to 100 kHz, for copper wires. As you can see, by 1 kHz it is around 0.1”, and at 20 kHz the skin depth is only 0.018”, with T = 0.025”. This is for an isolated wire; parallel or coaxial conductors cause a slight (~3%) change.
How much this matters in audio circuits is a matter of debate (of course). The table below shows the diameter of various wire gauges commonly used. Note that stranded or solid wire type has little impact on these calculations, though d.c. resistance is just a hair higher for stranded wire. Litz wire, bundles of smaller-diameter insulated wires, can be used to reduce the impact of skin effect. At 20 kHz, all the diameter of 22-gauge wire or smaller is utilized, and a.c. and d.c. resistance are essentially the same. Larger wire will be impacted by skin depth, with only about 31 % the diameter of a 12-gauge wire being utilized to carry signal current. However, note that the d.c. resistance of AWG 12 wire is only about 10 % that of AWG 22, so even after giving up so much due to skin effect, you are still better off than using the smaller wire.
In the real world interconnect impedances are so much higher than wire resistance (for typical cables) that skin depth is a non-issue, IMO. For speaker cables, while there is a clear argument for larger gauges to improve damping factor and provide high current capacity, skin depth is generally not a concern because the cables are larger and higher impedance can usually be tolerated at higher frequencies. Recognize that the d.c. resistance of a 10-foot piece of AWG 12 cable is only 0.016 ohms, still a very small number compared to the impedance of most speakers, so if skin depth doubles or triples that value at 20 kHz it is still a very small fraction of the load impedance, and much smaller than the output impedance of most amplifiers at 20 kHz.
https://en.wikipedia.org/wiki/Skin_effect