Full story: https://www.headphonesty.com/2025/01/headphone-jacks-slowly-making-comeback/

Trouble is they say this about every new network switch but what they dont tell you is if you use a fibre network instead of copper then noise isn’t an issue because a fibre network uses light. Oh it’s also a lot cheaper than any “audiophile” switch
A fibre network sounds pretty amazing too

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

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.