Speaker cables - what size?

Discussion in 'Cables & Switches' started by blackmax, Sep 16, 2007.

  1. blackmax

    blackmax
    Standard Member

    Joined:
    Sep 3, 2007
    Messages:
    11
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    1
    Ratings:
    +0
    Dear All,
    I have read with interest the positive comments on the site about VanDamme speaker cable for my AV system and have decided this is the way to go. What diameter though 1.5mm, 2.5mm or 4mm?
    I'm going to use it for a Sony ES3200 amp and KEF KHT5005.2 speakers in 5.1format? :rolleyes:
     
  2. Alan Mac

    Alan Mac
    Active Member

    Joined:
    Feb 13, 2007
    Messages:
    1,459
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    66
    Location:
    Highlands of Scotland
    Ratings:
    +248
    Andy,

    The only electrical requirement is that the speaker cable resistance is less than about 5% of the loudspeaker nominal impedance. For an 8 ohm speaker that is 0.4 ohms.

    The resistance of the speaker cable depends directly on its length and inversely on the cross-sectional area of the copper conductor.


    1.5 mm^2 copper conductor has a resistance of 0.0268 ohms /m loop

    2.5 mm^2 copper conductor has a resistance of 0.0166 ohms / m loop

    4.0 mm^2 copper conductor has a resistance of 0.0104 ohms / m loop


    e.g.

    If the speaker cable needs to be 8 m long feeding a nominally 4 ohm loudspeaker. What size cable is required?

    Using our 5% rule the cable loop (go and return) resistance should not exceed 4 ohms / 20 = 0.2 ohms

    So we should ideally not exceed 0.2 ohms / 8 m = 0.025 ohms / m loop

    1.5 mm^2 conductor, at 0.0268 ohms / m loop, just exceeds this limit but is near enough to be satisfactory.


    Alan
     
  3. blackmax

    blackmax
    Standard Member

    Joined:
    Sep 3, 2007
    Messages:
    11
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    1
    Ratings:
    +0
    :thumbsup:
    Alan,
    Thanks for the advice. The rear speaker lenghts will be 7m and the front/centre 2m. I think to be on the safe side I will get the 2.5mm cable.

    Andy
     

Share This Page

Loading...