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Please folks, this is a good resource. http://hyperphysics.phy-astr.gsu.edu/hbase/electric/miccur.html#c1
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This audio cable business is getting out of hand...
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JustAnandaDourEyedDude
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That is a very clear explanation, thanks for posting. I stand corrected. The travel of an electrical signal is the propagation of an electric potential wave through the conductor, I guess, while the flow of electricity is the actual flow of charge carriers at their drift speed, which is much slower. It makes sense in hindsight, for how could electrons with a non-zero mass travel at the speed of light? Glad I learnt something new.
Edit: Similar to an acoustic wave, in which the speed of sound is much higher than the induced speed of the particles of the medium. The pressure wave is the analogue of the electric potential wave.
Edit 2: This also explains how the little light in the fridge comes on so quickly when I yank the door open to check if it really went off when the door was shut.
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It's Just Wire!
Michael Fremer recently posted some files to compare: recorded through different high end speaker cables. People in the comments thread saying they hear obvious differences. There was a problem with the original files (some L/R swapped, also difference in loudness) and someone in the thread I think fixed them and normalized them.
FWIW:
https://www.analogplanet.com/content/its-just-wire-1#comments
Michael Fremer recently posted some files to compare: recorded through different high end speaker cables. People in the comments thread saying they hear obvious differences. There was a problem with the original files (some L/R swapped, also difference in loudness) and someone in the thread I think fixed them and normalized them.
FWIW:
https://www.analogplanet.com/content/its-just-wire-1#comments
Wow, it took some work to be either that dishonest or that incompetent.
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I think Mr. Fremer decided years ago that all his critics are motivated solely by envy and does not take these listening comparisons seriously at all. IIRC he posted some vinyl rips that were simply excruciating.
It is frequency-dependent once you get to higher frequencies (RF), but pretty flat at audio frequencies.
Strictly speaking, that tells us nothing at all, but we can be generous and assume the output impedance is given in ohms. The other numbers are useless without knowing the conditions under which they apply. The maximum length depends on cable parameters and acceptable signal degradation. Maybe they mean that the maximum length is 1360 ft if loss is to be limited to 0.1 dB at 20 kHz. If so, it still only applies to certain cable types, which they should have specified. Proper interface specs rarely include an explicit maximum cable length, instead bounding the signal degradation at the far end. Where length limits exist (Ethernet, USB), they are determined by propagation delay, not signal quality.
Although latency/propagation delay is a limitation of some interfaces, length limits due to signal integrity occur quite frequently in the high-speed serial data and RF worlds...
Indeed. High speed serial and RF. Not audio.
Yes, there is a practical limit, but I've rarely seen it specified explicitly. HDMI, for example, doesn't specify a maximum length. If you can somehow make a cable that delivers the required signal quality after 100 metres, that's allowed.
Protocols other than audio were mentioned, but even for audio there can be problems for large installations (concert halls, stadiums, etc.) For homes the usual issue is noise in low-level lines (and even then it is more likely to be a ground loop than actual EMI in my experience); noise and loss in speaker cables or even frequency response changes are rarely an issue. IOW not an issue in consumer installations unless something pathological is going on. And yes, many of us have seen such pathological setups...
I agree with you. I don't know anything about HDMI (I do have the spec downloaded, someplace, but I'll take your word for it). Mostly in my world (currently PCIe/SAS/SATA) the specs are not explicit but rather reflected in specified max/min Rx/Tx signal levels and various insertion loss specs. We know what length cable was targeted in developing the spec but it is not specified explicitly. Sometimes there is a graph that says "don't be worse than this" but again an actual length is not specified. Part of that is because cables are not the same in the RF world; one 6 m cable might work fine, and another fail, and when you measure them the loss difference is obvious. Then there are those who have an extra 10+ dB loss on a board and wonder why a cable that works on one system with 3 dB loss does not work on another with 15 dB loss...
Again, the only reason I commented was because cables for things other than audio were mentioned.
I think we're saying the same thing.
Guddu
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This SKW RCA interconnect has got good user reviews on Amazon and looking good for the price.
Anyone used it here?
View attachment 64403
Anyone used it here?
View attachment 64403
That's pretty expensive and doesn't even seem to be proper coax.
The HDMI spec is 50'. Have never seen one longer than that. For longer lengths you need cat6 and convertsers, than you get 300'. And a singal coax still carries dozens of HD channels for long distances. My diy coat hanger antenae thru 100' of coax gives me the best HD picture/5.1 surround I can get (better than cable, netflix, youtube) other than bluray, and it picks up 10HD channels, so why was expensive HDMI needed? Does anyone know how this HDMI scam got started?
