XLR or Speaker Cable

Discussion in 'Accessories, Cables, and Remotes' started by Tony#E, Sep 21, 2004.

  1. Tony#E

    Tony#E Extra

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    I am planning to have my audio rack at the back of my theater. Am I better off running an extra long XLR cable from the preamp to a 3 channel amp in the front, or keep the amp together with the rest of the system and just run a long set of speaker cables? I'm looking at a 30 foot run. If I use XLR the amp will not be surge protected.(The surge protection will only be at the rack)

    Tony
     
  2. ThomasW

    ThomasW Cinematographer

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    IMO, longer interconnects and short speaker wires are the best way to go, particularily if you're able to run balanced
     
  3. Stephen Hopkins

    Stephen Hopkins HW Reviewer
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    Tony,

    If you decide to run XLR I would get some kind of surge protection for the amp up front, I know a couple of companies make small 1 or 2 plug surge protectors that are very small, I use one intended for laptop computers in hotels. They're pretty inexpensive too since they're not required to handle as much current draw from several high-draw devices.

    Thomas,

    I'm assuming balanced would negate this argument, but wouldn't longer interconnects offer up more opportunity for RF interference since they carry a low level signal... and speaker cable (of an appropriate gauge for the length of the run) be much less likely to pick up any RF interference since they carry a high level signal? I know balanced XLR uses a positive and negative potential difference of the same signal so that any interference in one is duplicated in the other and the sum is still the same as the original signal, but how is this any more effective than a simple high level signal that's high enough in potential that RF simply doesn't affect it?

    Assuming balanced, are you saying would it be better to use the interconnects because at the lengths he would probably be running (especially if going around the room) you would need a pretty heavy gauge speaker wire (12ga should do it) to completely rule out any chance of resistance issues within the wire? If so, I run 16ga to my surrounds and the runs are right up to the 50ft max recommended for 16ga & 8ohm loads. I haven't heard any degradation in sound, and I used to run 14ga for the same run until the copper started to discolor inside the cable. 14ga or 12ga should eliminate any possibility of resistance issues at 30 ft, even if the speakers represent a 4ohm load. I'm guessing the 14ga or 12ga would be cheaper and easier to find (lowes of home depot are easier to find than pro-audio shops).

    No disrespect intended and I'm sure you're a bit more knowledgable on the subject than I am, just curious in your reasoning based on my own knowledge of both technologies.
     
  4. Wayne A. Pflughaupt

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    You really can’t compare the rears with the fronts. The rears are never the center of your focus for critical listening, since they’re generally carrying only ambient information. Not to mention you’re talking about a Dolby Digital signal, for crying out loud - a lossy compression scheme.

    Meanwhile, back at the front of the room, the focal point for critical listening, where often the signal source is not digitally compressed audio: Certainly, there is virtually no resistance factor at all with long interconnects and short speaker wiring. And although thirty-ft. isn’t really that long of a speaker cable run, 12ga. wire won’t entirely eliminate the resistance factor.

    But that doesn’t necessarily mean there will be any “degradation” in sound. That is entirely dependent on the particular speaker – i.e., how sensitive it is to minute changes in resistance. Naturally, speakers with lower nominal impedance ratings, speakers that use low-ohm drivers, and speakers whose impedance drops to extremely low levels at critical frequencies will be more subject minute resistance changes than speakers that don’t have those issues.

    Regards,
    Wayne A. Pflughaupt
     
  5. ThomasW

    ThomasW Cinematographer

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    Stephen,

    Nope, unbalanced runs don't change my contention.

    In my HT I run 35' lengths of unbalanced IC's. They're made from a coax with a full shield. I don't have any RFI problems.

    As long as the op-amps in the circuits will tolerate longer runs (meaning they don't oscillate) I think long IC's and short speaker wires are the best bet.

    When I get a balanced active XO (it's the only piece of gear in the system without balanced circuits) I'll convert all my IC's to balanced.
     
  6. Stephen Hopkins

    Stephen Hopkins HW Reviewer
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    Thomas, you still haven't said why ICs over speaker wire. Even with ICs that are RFI free it seems that the posibility of RFI is still there and that ICs that can reject RFI that well would cost more to buy/build than equivalent lengths of 12awg speaker wire that have no chance of RFI because of the nature of a high level signal as well as the added benefit of being very inexpensive.
     
  7. Tony#E

    Tony#E Extra

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    Thomas,
    since your in favor of XLR...
    What do you think of custom length cables available
    on EBay? I've seen a guy on there that is making them.
    Or would you spend the cash on a set of factory made, if they're even made?

    Tony
     
  8. ThomasW

    ThomasW Cinematographer

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  9. Chu Gai

    Chu Gai Lead Actor

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    The theoretical answer is long interconnects and short speaker cables. In fact, theoretically, you just ought to weld the amp outputs to the speaker inputs. With the vast majority of preamps, the frequency response of the interconnect/preamp combo is phenomenally linear. For example, Fred Davis, who has published in the JAES has stated the following.


    So, if you don't mind dropping a few extra dollars, go with the long XLR's. Doesn't mean you'll hear a difference, but theoretically you know [​IMG]
     

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