speaker wire length

[griffinconst]

Hope this isn't too dumb a question but, I've read that one should have wire of equal legnth to the main speakers. What about to the center? I can make the connection in 3'-4', but the wires to my mains are 15'. Should the center be 15' to match the mains or is the shortest possible legnth the best? If I can reach one main with 6' and the other in 15' should I make them both 15' or again is shortest best?

 

[TLS Guy]

Hope this isn't too dumb a question but, I've read that one should have wire of equal legnth to the main speakers. What about to the center? I can make the connection in 3'-4', but the wires to my mains are 15'. Should the center be 15' to match the mains or is the shortest possible legnth the best? If I can reach one main with 6' and the other in 15' should I make them both 15' or again is shortest best?

That advice came from someone not thinking, or may be too much. Just cut the cables to the length you need and don't listen to the funny mags.

 

[mike c]

no it is not necessary for the speaker wire lengths to be the same. even a thousand foot spool of wire should have milliseconds of delay IF ANY at all.

edit:
i was wrong on the millisecond part
http://www.rfowkes.com/WireLengthTimeDelay.html

they're talking nanoseconds

 

[mtrycrafts]

no it is not necessary for the speaker wire lengths to be the same. even a thousand foot spool of wire should have milliseconds of delay IF ANY at all.

edit:
i was wrong on the millisecond part
http://www.rfowkes.com/WireLengthTimeDelay.html

they're talking nanoseconds

Yes, nanos but imagine the resistance of a 1000ft of 12ga is 1.62 Ohms and inductance?, Capacitance?

 

[lsiberian]

electricity travels at near light speed. As a result traveling 15 meters takes
the slowest wires would run around 200 million meters a second(very conservative estimate) at 15 meter run would be
15/200,000,000 seconds

That comes out to 75 nanoseconds. Now tell me if you can notice a difference of 75 nanoseconds?

Whoever said that should be required to take that nasty E&M physics course I had to take. That class was torture hehe.

 

[griffinconst]

Thanks a lot you guys. I seem to see the same names answering my never ending questions and I really appreciate it.
I have always loved listening to music, I also play a few instruments. Now that I finally have the funds, I want to learn all that I can and get some good equiptment.
THANKS AGAIN FOR ALL YOUR HELP! Many dumb questions to follow.
KG

 

[highfigh]

That advice came from someone not thinking, or may be too much. Just cut the cables to the length you need and don't listen to the funny mags.

Unfortunately, it's not only the funny mags that advocate this. I went to CEDIA in '05 and along with the equipment manufacturer displays, they have installer, project management, system design, lighting control and other training. The scheduling manager where I was working decided that he knew what classes I should take instead of the classes I wanted, so he sent some of us to an audio calibration session. I had already seen the "instructor" at CES and he spent more time telling us how cool he and his company were. One of the things he recommended for all systems was equal length speaker cables. Someone asked of the excess should be coiled up behind the wall or rack and he answered that it really didn't matter. I stopped listening to him at that point.

 

[highfigh]

electricity travels at near light speed. As a result traveling 15 meters takes
the slowest wires would run around 200 million meters a second(very conservative estimate) at 15 meter run would be
15/200,000,000 seconds

That comes out to 75 nanoseconds. Now tell me if you can notice a difference of 75 nanoseconds?

Whoever said that should be required to take that nasty E&M physics course I had to take. That class was torture hehe.

The speed of light is approximately 300,000 Km/sec. The old standard in was taught as 186,282 miles/sec, which comes out to just under a billion ft/sec, so 1' of travel is about 1 nanosecond. This is why a 15' difference in speaker cables won't be audible when most people can't hear a delay of a millisecond.

 

[Adam]

I'm too lazy to Google it (for shame, for shame), so I'll ask here for a refresher. You mentioned the speed of light in a vacuum, but what is the speed at which electrical current flows down a copper wire? That's not a challenge! I'm just curious, because I know that the speed of light depends on the medium.

 

[highfigh]

I'm too lazy to Google it (for shame, for shame), so I'll ask here for a refresher. You mentioned the speed of light in a vacuum, but what is the speed at which electrical current flows down a copper wire? That's not a challenge! I'm just curious, because I know that the speed of light depends on the medium.

For design purposes, they generally use the speed of light as the speed of electron movement in wire. Being a good conductor, it's close enough for all practical purposes. In an electronic device, it's also not large enough to make much difference if not quite at that speed.

Electronics- always precise, never exact.

 

[Adam]

Thanks, highfigh! I got off my mental behind and looked it up after you reminded me of this. I came across at least one site that I read about a year ago.

 

[highfigh]

Thanks, highfigh! I got off my mental behind and looked it up after you reminded me of this. I came across at least one site that I read about a year ago.

The only reason I know some of this stuff is that I had to, when I was in school. I'm still not sure why architecture students needed to know the voltage required for lightning to strike the Earth, given the cloud height of 5000' and using the standard dielectric coefficient of air, but hey- he was the teacher.

 

[mtrycrafts]

.... That class was torture hehe.

Hey, a new torture tool Sell it, it might be legal

 

[mtrycrafts]

I'm too lazy to Google it (for shame, for shame), so I'll ask here for a refresher. You mentioned the speed of light in a vacuum, but what is the speed at which electrical current flows down a copper wire? That's not a challenge! I'm just curious, because I know that the speed of light depends on the medium.

Well, we are talking electric signals, not actual electron movement. So, signal propagation would depend on dielectric of the insulation, hence the above poster's 200km/sec, a 66% propagation velocity Still plenty fast.

 

[mtrycrafts]

Unfortunately, it's not only the funny mags that advocate this. I went to CEDIA in '05 and along with the equipment manufacturer displays, they have installer, project management, system design, lighting control and other training. The scheduling manager where I was working decided that he knew what classes I should take instead of the classes I wanted, so he sent some of us to an audio calibration session. I had already seen the "instructor" at CES and he spent more time telling us how cool he and his company were. One of the things he recommended for all systems was equal length speaker cables. Someone asked of the excess should be coiled up behind the wall or rack and he answered that it really didn't matter. I stopped listening to him at that point.

You should have played games with him asking why that is, and to explain it in technical terms if he would. Then ask more whys
I have embarrassed a few folks with such moves.

 

[lsiberian]

The speed of light is approximately 300,000 Km/sec. The old standard in was taught as 186,282 miles/sec, which comes out to just under a billion ft/sec, so 1' of travel is about 1 nanosecond. This is why a 15' difference in speaker cables won't be audible when most people can't hear a delay of a millisecond.

That is the speed of light in a vacum not necessarily in every medium. In a coaxial sheilded copper cable the slowest I would expect is a 1/3 slowdown in the speed of an electromagnetic wave. Few wires would suffer from this slowdown, but it's giving the perpetuator the best hand possible and showing their ignorance. 15 meters was my distance with a very bad speed and it's still very low. Funny thing is that we can send data across the ocean in less than a second and this guy thinks that the wire length in your house even matters. It takes a lot of wire to get to a millisecond. And buy the time you get there you will have bigger issues than delay from wire travel lol.

 

[lsiberian]

You should have played games with him asking why that is, and to explain it in technical terms if he would. Then ask more whys
I have embarrassed a few folks with such moves.

Lol. The best question to ask would be how long does it take for current to travel a meter in a wire? Then lay the smack down.

 

[lsiberian]

Hey, a new torture tool Sell it, it might be legal

Just be glad wire works lol.

But seriously a physics course should be required for anyone certified in the sound field. Wave physics and electricity need to be understood. If a person doesn't understand they should really seek to learn as much as possible.

Of course I see the world as a collection of waves hehe. It's fun!