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Basic speaker cable question
Basic speaker cable question
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Old 25th January 2019, 09:47 AM   #31
Kay Pirinha is offline Kay Pirinha  Germany
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Quote:
Originally Posted by kodabmx View Post
+1

"Special" audio and speaker cables are basically snake oil, and most people wouldn't tell the difference between that fancy cable, lamp cord, or barbed wire.
...and the audiophools with their golden ears will tell you that DBT's aren't an apt way to discern ...
Best regards!
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Old 25th January 2019, 11:34 AM   #32
DF96 is offline DF96  England
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Quote:
Originally Posted by steveu
Most expensive speaker wire is bad science, which focuses on DC resistance when what is more important is the transmission line impedance.
No. Concentrating on DC resistance (up to a point) is the right thing to do. Inductance is far less important, unless some unusual cable construction is used which artifically increases inductance beyond normal levels. This is sometimes found in daft DIY cables or expensive 'highend' cables.

Transmission line characteristic impedance for a speaker cable is almost irrelevant. In the audio frequency region it is non-resistive and varies with frequency, so you can't match it even if you wanted to. There may be some small benefit for amplifier stability and RF pickup if you achieve a rough match at RF by adding a Zobel network at the far end, but this is not critical and most setups work fine without it.
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Old 25th January 2019, 12:01 PM   #33
scottjoplin is offline scottjoplin  Wales
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Originally Posted by Kay Pirinha View Post
...and the audiophools with their golden ears will tell you that DBT's aren't an apt way to discern ...
Best regards!
You noticed!
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Old 25th January 2019, 12:12 PM   #34
Moondog55 is offline Moondog55  Australia
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Reminds me of a post here years ago, by a respected speaker builder, recommended using a bigger return wire than input wire as far as DC resistance went and for years I have been making up speaker cable with cheap 3-core flex, using the brown P+ wire for the speaker in and the coupled Blue and Green for the N- return. They didn't sound any better but I saved a lot of money as people are always throwing away vacuum cleaners with very long leads attached ready for salvage, sometimes 2-core but often 3-Core
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Old 25th January 2019, 06:19 PM   #35
Speedskater is offline Speedskater  United States
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Quote:
Originally Posted by steveu View Post
Perhaps if you sink a ground rod at each speaker and one at the amp, you might have a point. But a very important aspect of low impedance connections is the inductance that results from the loop area between conductors, which is why even power lines alternate positions. "Ground" voltage does not magically go to zero. It's more like the water level on the ocean. If you pour current into "ground", the level rises around that point. The exact ground voltage is different than it is a few inches away so you see PCB ground traces running in parallel, not connecting together until they reach a single point ground. It's call avoiding a "ground loop". You may also want to study transmission line theory.

..............................................
If "ground" in this case is Planet Earth, then current never goes to "ground". While it may travel thru "ground", it always goes back to it's power source.

Note that Planet Earth will never act as a sink or sump for bad electricity.
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Old 25th January 2019, 08:41 PM   #36
kodabmx is offline kodabmx  Canada
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Basic speaker cable question
Excepting radio? :P
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Old 25th January 2019, 09:09 PM   #37
academia50 is offline academia50  Argentina
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Originally Posted by Speedskater View Post
If "ground" in this case is Planet Earth, then current never goes to "ground". While it may travel thru "ground", it always goes back to it's power source.

Note that Planet Earth will never act as a sink or sump for bad electricity.
Humm, I'm not sure about that ....
Have you tried switching on a common resistive filament lamp with one cable in the socket and the other one grounded? The potential difference causes it to turn on, a current will circulate because the electric generator of the light power plants are connected to ground, and it acts as a conductor.

It is common to confuse the neutral and live of the outlets (alternating current) as if they were negative and positive from a direct current source. The current that circulates through the audio cables is alternating, if DC current circulates, the amplifier and / or the speakers pass to a better life.

Last edited by academia50; 25th January 2019 at 09:20 PM.
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Old 25th January 2019, 09:46 PM   #38
Francisdumas is offline Francisdumas  Canada
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This is great, I much prefer science than alchemy, this is why I came here to ask this question. I want to thanks every responders and I hope others will find this thread helpful too. I think I will enjoy my current set-up since it already sounds amazing and stop thinking “what if cables would make it 1% better”. Right now I’m using Ethernet wire cables, hard colour together and dash colour together. I can’t hear a difference using 2 cables or 1 cable so I stick to 1.
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Old 26th January 2019, 12:50 AM   #39
PRR is online now PRR  United States
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Originally Posted by academia50 View Post
....Have you tried switching on a common resistive filament lamp with one cable in the socket and the other one grounded? ....
You mean, to a dirt-rod?

I have. The bulb is dim.

This with a nominal 120V 0.5A (60W) lamp and 7 feet of rod under my septic field; and the power company dirt-rod (2 8') on the far side of the field.

My summary data suggests around 120 Ohms from a full size dirt-rod to another rod on the same land, implying 60 Ohms from one rod to an imaginary "true earth".

My 60W lamp is nominally 120V/0.5A= 240 Ohms, so 60-120 Ohms in series makes it dim. (And a dim bulb is a lower resistance, so I was getting like half of line voltage.)

This incidentally means I can NOT blow a breaker with "earth current" literally through dirt. Three 60 Ohm rods is 20 Ohms, marginally under the NEC goal of 25 Ohms, but 120V/20r is only 5 Amps, and my smallest breakers are 15A.

Things CAN be different on the damp salty coast of Florida.

Last edited by PRR; 26th January 2019 at 12:52 AM.
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Old 26th January 2019, 09:34 AM   #40
DF96 is offline DF96  England
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Quote:
Originally Posted by academia50
Humm, I'm not sure about that ....
Have you tried switching on a common resistive filament lamp with one cable in the socket and the other one grounded? The potential difference causes it to turn on, a current will circulate because the electric generator of the light power plants are connected to ground, and it acts as a conductor.
You are agreeing with him. He said currents never go 'to ground', but can travel 'through ground'.

Quote:
Originally Posted by kodabmx
Excepting radio? :P
Sometimes radio uses ground as the other half of an antenna. This is because an antenna made of a conductor must have two terminals, but in some cases the second terminal can be hard to spot - which leads some people to claim that some antennas only have one terminal. Ground does not make a good half-antenna, but sometimes it is all we have. Even when used for radio, ground is not a magic sink for unwanted currents.
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