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Audio and Video Talk
General Discussion
Cable lengths - here's a question for all of u ;)
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<blockquote data-quote="gbyleveldt" data-source="post: 80227" data-attributes="member: 122"><p>In short, at audio frequencies and non-co-ax cables, cables do not need to be the exact same length. Obviously you wouldn't want to have a 100m cable and a 1m cable as the cable resistance will start to affect the signal (especially at high frequencies and currents).</p><p></p><p>[I had to dust off the books for this stuff:]</p><p></p><p>Also, the velocity factor is something to consider at high frequencies. This limits the speed at which a signal travels in a cable (esp co-ax). It's usually given as a fraction of the speed of light and is different for each cable as the cable construction specifically affects it. RG59's velocity factor is about 0.6-0.7 the speed of light. Where this can affect you and me in everyday life is when we have a piece of co-ax between our transports and dacs (remember we spoke about it the other night?) and how the length of the cable can affect the SPDif fundamental. The last thing you want is for the characteristic impedance of the cable (a function of the length) to form a tank circuit, thus affecting the response of the cable at the frequencies of concern. There's also the issue around the length of the cable being a multiple of the wavelength of the signal, causing potential backscatter issues in cables that aren't perfectly terminated.</p><p></p><p>So, in short, the length of a cable can affect a signal in certain instances.</p></blockquote><p></p>
[QUOTE="gbyleveldt, post: 80227, member: 122"] In short, at audio frequencies and non-co-ax cables, cables do not need to be the exact same length. Obviously you wouldn't want to have a 100m cable and a 1m cable as the cable resistance will start to affect the signal (especially at high frequencies and currents). [I had to dust off the books for this stuff:] Also, the velocity factor is something to consider at high frequencies. This limits the speed at which a signal travels in a cable (esp co-ax). It's usually given as a fraction of the speed of light and is different for each cable as the cable construction specifically affects it. RG59's velocity factor is about 0.6-0.7 the speed of light. Where this can affect you and me in everyday life is when we have a piece of co-ax between our transports and dacs (remember we spoke about it the other night?) and how the length of the cable can affect the SPDif fundamental. The last thing you want is for the characteristic impedance of the cable (a function of the length) to form a tank circuit, thus affecting the response of the cable at the frequencies of concern. There's also the issue around the length of the cable being a multiple of the wavelength of the signal, causing potential backscatter issues in cables that aren't perfectly terminated. So, in short, the length of a cable can affect a signal in certain instances. [/QUOTE]
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Audio and Video Talk
General Discussion
Cable lengths - here's a question for all of u ;)
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