Splicing speaker cable - A no no?

Discussion in 'Archived Threads 2001-2004' started by Brian Ooten, Mar 28, 2002.

  1. Brian Ooten

    Brian Ooten Extra

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    I have one final run left to complete my HT setup. I have two pieces of cable that, if spliced together, would accomodate me. If not, I have to go buy another spool/section of 40 ft cable. So is splicing Ok or a no go?

    Thanks,

    Brian
     
  2. Dave Poehlman

    Dave Poehlman Producer

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    It depends who you ask.

    An audio purist would probably gasp at that question.

    While a more casual listener will have no problem with it. As long as you don't mix up your polarities and ensure you have a good connection by using wire nuts, the splice should work as well as a whole piece. (I assume this is standard speaker wire we're talking about)
     
  3. Brian Ooten

    Brian Ooten Extra

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    yeah its standard 12 ga. speaker cable, looks just like the Monster Cable but its made by Home Theatre(Lowe's).

    Thanks for the input!

    Brian
     
  4. RonM

    RonM Extra

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    I ran wires before my house was built. Months later when it was time to buy and place my new speakers I changed the location somewhat requiring a splice....I don't think I'm missing anything but then again it is just for my rear surrounds.

    I'd say go for it if this is a rear speaker run!
     
  5. Pat K

    Pat K Stunt Coordinator

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    Screw wire nuts, just use a little electrical tape. $100 says you cant tell the difference in sound.
     
  6. ColinM

    ColinM Cinematographer

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    Solder and heat shrink.
    [​IMG]
    A splice is just like a connection, banana or otherwise.
     
  7. steve nn

    steve nn Cinematographer

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    I did a splice on one of my surrounds and did not effect as I can tell.Some will say I am loosing out big time.If I was I would not do it.[​IMG] [​IMG] [​IMG] The meter never lies.
     
  8. Juan Castillo

    Juan Castillo Second Unit

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    ColinM has the right idea. If you have the tools that is.. Soldering and using heatshrink will make a solid connection and IMHO is neater than tape or wirenutz. I would displace the cuts in wire so that the two soldered ends are not side by side.. see mock diagram

    ---------------- ------- +

    --------- -------------- -

    I actually put solder on all the tips of my speaker cable. It makes for a neater look, it doesn't fray when trying to put into a spring or push terminal, and it won't oxidize like bare copper will. Which might make for a cleaner connection.??? My unedumicated theory tho...
     
  9. Brian E

    Brian E Screenwriter

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    How about splicing different gauges? The speakers I was planning on using as temporary rears are from a book shelf system and have wire approx 6' long attached. They are about 20ga. & the cabinets are sealed shut, so I can't get inside to replace the wire entirely. Would it be best to solder from the end of the existing wire or cut off the wire about a foot from the cabinet and splice? I'm thinking 16ga. or so on these. They are a stop gap for about 6 months until I can move my DM600 S3's to rear duty and get some 601's or 602's for the fronts.

    Thanks
     
  10. Wayne A. Pflughaupt

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    Brian O, Brian E, and anyone else who needs/wants to know,
    As a former pro installer I can assure you that splicing is fine. The only problem with splicing is that (obviously) the structural integrity of a cable is compromised. Therefore if there is ever a problem in the future where that cable is involved, the splice point is the first thing to check.
    As far as how to accomplish the splice there are several methods, all with their own specific strength and weaknesses:
    • Twist and tape: This is the worst method and is not recommended. A pull on the wire will usually make the splice separate. Furthermore, tape tends to loosen over time as the adhesive breaks down, especially cheap electrical tape. If you must twist and tape, use only the most expensive 3M electrical tape - usually around $3 a roll at the hardware store. It's the only kind that I've found that won't loosen with time - indoors at least. Twist and tape splices in an attic at your own peril.
    • Twist-on wire nuts are designed primary for use with solid-gauge wire, like house electrical Romex. However they can work well with stranded wire if installed properly, and make for excellent connectivity.
      The key to a good twist-nut splice is selecting the correct wire nut size for the gauge of cable you are using. Red nuts are usually best for 12ga. stranded speaker wire, yellow for 14ga., orange for 16ga., etc. (Please note these are not exacting guidelines: The more individual strands there are in a wire of a given gauge, the thicker it is physically, thus possibly requiring a larger wire nut.)
      Do not twist the wires before they are inserted into the nut – let the action of the nut do that. The nut should twist on very tightly, to the point where it will no longer turn. If the nut never gets tight enough to stop turning, it will not be a secure splice and will easily pull apart. Usually this is an indication that the nut is too large.
      A wire nut splice does not need to be taped if done properly. The insulation on the wire should not be stripped back so far that bare wire extends below the base of the nut.
      If they are done right, wire nuts are reasonably sturdy and can withstand a good amount of pressure or pull on the cable. Indeed, each splice should be given a sharp tug to make sure the connection is secure. The final product is rather bulky and unseemly, and as such wire nuts are best for “out of sight” splices: in-wall, attics, etc.
    • Crimped caps or nuts are similar in application and appearance to twist-on wire nuts. Again, there are specific sizes for the gauge of wire you are using, and the insulation on the wire should not be stripped back so far that bare wire extends beyond the base of the nut.
      The cap should be firmly and fully crimped with a correct-sized jaw of a crimping tool, and the connection should be subjected to a pull-test afterwards. Crimped caps, if done correctly, are about as sturdy as twist-on nuts and require no taping.
    • Insulated butt splices are installed in-line and as such are the best splicing method where there are concerns for aesthetics. Butt splices are the choice if the spliced wire is to be run around baseboards.
      Like nuts and caps, there are specific sizes of butt splices for specific gauge size: Yellow butts are for 10-12ga. wire, blue for 14-16ga. wire, red or pink for 18-20ga. wire.
      With butt splices, the insulation should be stripped back only far enough for the bare wire the fully seat in the metal sleeve. The insulation should fully butt up against the internal metal sleeve, and be fully covered by the outer plastic cover. In other words, no bare wire should be exposed.
      Like crimped nuts, butt splices should be firmly and fully crimped with a correct-sized crimper jaw, and the connection should be subjected to a pull-test afterwards. Butt splices if done correctly are about as sturdy as twist-on nuts and crimped caps and require no taping.
      Crimped devices are designed to be used solely with stranded wire. Under no circumstance should butt splices or crimped caps ever be used with solid-core wire like Romex, ect.
    • Soldering is probably the most robust method of splicing. A successfully soldered splice will be as strong as the cable itself. However, soldering requires considerable more skill than crimped or twist nut splices and requires specialized tools, namely an adequate soldering iron. Good soldering irons or soldering guns usually start at about $40.
      Soldering becomes more problematic as wire gauge increases; a 14ga. splice (which will total in overall size greater than 12ga.) is the maximum sized wire that can reasonably be soldered with a 35-40 watt iron. Irons with marginal power will deliver the available heat most effectively with a large or broad tip, as opposed to a thin, “pencil point” tip.
      Soldering a 12ga. splice with a low-powered iron (35-40 watts) is not recommended, because the total AWG of two 12ga. wires twisted together is very large - about 9ga. The problem with soldering heavy gauge wire with a light-duty iron is that the wire is very slow to heat, and consequently the insulation starts to melt. Bottom line, if one has to solder two pieces of 12ga. speaker wire, a 100 watt solder gun or iron is recommended. Splicing 10ga. or larger will probably require a torch, which will certainly ruin the insulation. Large-sized twist-on wire nuts are the most economical way to splice 10ga. wire.
      A problem with soldering is that the flux residue over time becomes a corrosive element that can eventually eat through the wire and sever the splice. However, this is more a problem with very small-gauge wire (22ga. or less) than with large gauge wire.
      While twist-nuts and crimped connections provide their own built-in insulation for the splice point, soldering does not, so it must be insulated after the fact. The best, most effective, and durable insulator is heat shrink tubing.
      The tubing can be applied in one of two ways: An adequately-sized piece can be slipped over one of the wire leads before soldering, large enough to fully cover the splice and lapping over the insulation. After soldering the spliced section would be bent down with pliers to be parallel with the length of wire, and the heat shrink would then be slid over to fully cover the splice and all bare wire. This makes for a somewhat more “streamlined” splice (second only to the in-line butt splice), but with this method you have to make sure in advance the heat shrink is the right length and size. If not, you will have to cut the wire again and start over with a new solder connection.
      Alternately, the heat shrink could be applied after soldering by sliding a piece over both the wires and the splice - i.e., with both wires extruding from one end of the tube. This method has some “fudge factor;” if you cut the heat shrink too short or have the wrong size you can easily cut it off and install a new piece.
      It is important for the heat shrink to be a little loose at the tightest point (before heating). If it is so tight that it barely fits, it may very well split when you apply the heat.
      The heat shrink obviously need a heat source to shrink. The best thing to use is a heat gun (more specialized tools!). You can get (expensive) special heat guns made for that purpose at electronics hobby shops, but a common paint stripping heat gun from Wal-Mart will work fine, for under $20. Alternately a cigarette lighter, fireplace lighter, etc. can be used. The heat shrink will take direct flame, but extreme caution must be exercised not to melt the insulation on the wire. For best results, make sure to fully turn the wire when heating the tubing, to even distribute the shrinking process.
      Wrapping with electrical tape is not recommended for insulating a soldered splice because, as mentioned earlier, it does not hold up over time.
    As a general note (Brian E) all these methods except butt splices can fully accommodate wire of differing gauges. Butt splices are more limited: You can “step up” or “step down” wire gauge only as long as it is the same size wire that the butt splice is designed for (see color/gauge code above). In other words, using a blue butt splice you could transfer from 14 or 16 gauge (or vice versa) but not to gauges larger or smaller than that. Using too small a wire in a butt splice runs the risk of an unsecured crimp that can easily separate or pull out of the butt splice.
    Regards,
    Wayne A. Pflughaupt
     
  11. Juan Castillo

    Juan Castillo Second Unit

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    " Alternately, the heat shrink could be applied after soldering by sliding a piece over both the wires and the splice, with both wires coming out one end of the tube. This method has some “fudge factor;” if you cut the heat shrink too short or have the wrong size you can easily cut it off and install a new piece. "

    If this method is used, it is imperitive to use staggered cuts in the wire, so the two bare soldered wires do not touch!!!!! refer to my first reply in this thread with a mock diagram of what I mean.
     
  12. Brian E

    Brian E Screenwriter

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    Thanks Wayne. I've done quite a bit of splicing for various things before. Just wasn't sure about the different gauge thing. Everything I've done has been of the same gauge. I'm sure I'll solder as in my mind, right or wrong, it's the best way.
     
  13. Wayne A. Pflughaupt

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    Juan wrote:
     
  14. Juan Castillo

    Juan Castillo Second Unit

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    That is why I made reference to this

    " Alternately, the heat shrink could be applied after soldering by sliding a piece over both the wires and the splice, with both wires coming out one end of the tube. This method has some “fudge factor;” if you cut the heat shrink too short or have the wrong size you can easily cut it off and install a new piece. "

    Just so that someone that has never soldered would not cut both wires the same length, solder the extensions, and then put one piece of heatshrink over both wires.. What you would have then, is this

    ------------------ --------- +

    ------------------ --------- - with a single piece of heatshrink around both wires and both uninsulated solder points.

    are you saying that having the positive and negatives touching is ok? Forgive my ignorance, but with high power amps, I don't see how that can be possible.. That Wayne... is my point. If you are going to put a protective heat shrink sleeve over one, or both individual soldered wires, than of course there is no need to stagger, unless of course if you want a more stream line run. Its all preference tho.
     
  15. ColinM

    ColinM Cinematographer

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    Don't think to much into this, Juan. I'm pretty confident that everyone, especially Wayne, knows not to short out the wires.
     
  16. Juan Castillo

    Juan Castillo Second Unit

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    I've said my peace. I'm sure Brian got way more than he needed here huh? Oh well, like I said in that other thread, no disrespect to you Wayne...
     
  17. Brian Ooten

    Brian Ooten Extra

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    Excellent advice guys, I really appreciate it. I think I've got the point and should have no problem fixing my setup based on the advice given in this thread. Again thanks!

    Brian
     
  18. Wayne A. Pflughaupt

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    Juan,
    Not to worry, no offense taken. Re-reading my post I can see that I was a little unclear.
    One piece of shrink would go over the (+) and one over the (-), separately. The “two wires coming out of the end of the tube” are the two cut pieces you soldered together.
    I can see now what you are talking about is using a single, larger piece of heat shrink over both the (+) and (-) splices. This is another option that I didn’t mention, and you are right, of course, that you would have to stagger the splices with this method to avoid a short. In this case there would be four wires “coming out of the end of the tube.”
    Sorry for the confusion.
    Regards,
    Wayne A. Pflughaupt
     

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