Interconnect cable for Polk SDA II

I am making new speaker cables for my Polk SDA II's and wondered what is the optimum length interconnect cable if the speaker cables are 9.5' long? I would think you would want the interconnect cable length as close to the speaker cable length as possible. I have never seen the factory cables for these speakers so I don't even know what length they were.


  • Scott99Scott99 Posts: 33
    I would think excessive changes to the length of the interconnects and speaker cables could affect timing of the SDA. If the original interconnect cable was a minimum of 20'. What was the length of the speaker cables that came with the SDA's? Assuming they came with the speakers.
  • Scott99Scott99 Posts: 33
    Ok, thanks. I will stick with my theory that the interconnects should be as close as possible to the length of the speaker cables just in case it makes a difference. Thanks again guys for the information!
  • pitdogg2pitdogg2 Posts: 12,069
    F1nut wrote: »
    The length doesn’t make a difference. The quality of the cable used does.

  • FestYboyFestYboy Posts: 3,105
    Remember, the signal is traveling the speed of light... 2.036494e−8 of a sec for those 20ft
  • FestYboyFestYboy Posts: 3,105
    ^ for those not familiar with scientific notation, that number reads 0.00000002036494 sec.
  • Viking64Viking64 Posts: 3,669
    FestYboy wrote: »
    ^ for those not familiar with scientific notation, that number reads 0.00000002036494 sec.

    Well, that clears things up a whole bunch. :o :p

  • KennethSwaugerKennethSwauger Moderator Posts: 6,766
    edited August 2018
    In most cables electrical signals travel at about 2/3 the speed of light. The electrons inside the metal move at a snail's pace called the drift velocity. They don't have to move very far until they bump into another electron, which in turn bumps against another electron. Kind of like a line of tumbling dominoes.
    "And the house you live in will never fall down
    If you pity the stranger who stands at your gate" G.Lightfoot
  • FestYboyFestYboy Posts: 3,105
    Ok, so that makes it: C=y+(.5y)

    3.054741e-8 seconds.

    Point being: you can't detect the difference, even at 10 times that length.
  • Scott99Scott99 Posts: 33
    Well there are several other things to consider. You would not make your left speaker wire 5' long and your right 20' long. The longer cable would have added resistance, more length to be exposed to different types of interference, difference in capacitance, etc. Especially when lower quality materials are used to make the cables the less of it you want in the signal path. Most of us take great care to make sure all our speaker drivers are getting the same quality signal. Why would we not want to make the same considerations with our SDA drivers?
  • Scott99Scott99 Posts: 33
    My original question was asking "What is the optimum length interconnect cable if the speaker cables are 9.5' long?" The way I understand it. If you have 9 foot speaker cables and a 20 foot interconnect cable. Your SDA drivers have the equivalent of 29 foot speaker cables and your other drivers have 9 foot speaker cables powering them. I would think we would want to try and make the interconnect cable as short as possible to try and get the same quality audio signal to all drivers.
  • FestYboyFestYboy Posts: 3,105
    See my post on August 3rd.
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