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Is 16 ga adequate for an 80 foot speaker run?

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  • Is 16 ga adequate for an 80 foot speaker run?

    250 watts, speaker is high passed at 80-100 hz, so it's not producing any deep bass

    Thanks!
    Form does not follow function
    Form is simultaneous to function

  • #2
    Re: Is 16 ga adequate for an 80 foot speaker run?

    I won't directly answer you, I may be hesitant to do such but there are gauge/length calculators out there on the web to answer you.

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    • #3
      Re: Is 16 ga adequate for an 80 foot speaker run?

      Thanks Rotech

      I've seen a few charts that suggest I should be using 14 ga...

      But what I can't find is any info on "if the speaker is high passed"... doesn't the high pass mean I can get away with a thinner gauge? Perhaps not...
      Form does not follow function
      Form is simultaneous to function

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      • #4
        Re: Is 16 ga adequate for an 80 foot speaker run?

        Here is a chart of wire vs. length by Linkwitz...

        http://www.linkwitzlab.com/orion-faq.htm#Q10

        It's in context of a best-case scenario (no passive crossover), but it has some useful information to get you started.
        Bill Schneider
        -+-+-+-+-
        www.afterness.com/audio

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        • #5
          Re: Is 16 ga adequate for an 80 foot speaker run?

          Originally posted by lunchmoney View Post
          what I can't find is any info on "if the speaker is high passed"... doesn't the high pass mean I can get away with a thinner gauge?
          No it's irrelevant, the wire gauge required is based on the total distance being covered and the power level being delivered.
          Paul O

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          • #6
            Re: Is 16 ga adequate for an 80 foot speaker run?

            Originally posted by williamrschneider View Post
            Here is a chart of wire vs. length by Linkwitz...

            http://www.linkwitzlab.com/orion-faq.htm#Q10
            This is better, as it considers current as well:

            http://www.bcae1.com/images/swfs/spe...rassistant.swf
            But what I can't find is any info on "if the speaker is high passed"... doesn't the high pass mean I can get away with a thinner gauge? Perhaps not...
            Not. There are two considerations, the dB insertion loss and the cable current capacity. With a high passed signal power demand, and therefore current draw, is lessened, but that has no effect on the insertion loss. Where you can get away with using a lighter gauge, a much lighter gauge at that, is with the wiring of mids and tweeters inside the cab, where even the smallest wire doesn't present an insertion loss issue and you can take advantage of the reduced power/current requirement.
            www.billfitzmaurice.com
            www.billfitzmaurice.info/forum

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            • #7
              Re: Is 16 ga adequate for an 80 foot speaker run?

              As Paul O said, high passing at 80-100 Hz is irrelevant. 250 watts of power at 40 Hz vs 250 watts of power at 1 kHz, is still 250 watts. Of course, this assumes that you're truly pushing 250 watts above your high-pass frequency.

              At an 80 foot run x 2 conductors, you're looking at approx 1 ohm with copper wire. With an 8 ohm load, you're looking at dropping ~11% of your power in the wire and losing ~1dB of output. With a 4 ohm load, you're dropping ~ 20% of your power and ~2dB of output.

              EDIT: Oops, my calcs here are based on 18 ga wire.

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              • #8
                Re: Is 16 ga adequate for an 80 foot speaker run?

                Originally posted by 1100xxben View Post
                As Paul O said, high passing at 80-100 Hz is irrelevant. 250 watts of power at 40 Hz vs 250 watts of power at 1 kHz, is still 250 watts. Of course, this assumes that you're truly pushing 250 watts above your high-pass frequency.
                High passing at 80-100Hz may not be major, but it's certainly not irrelevant, as power density is reduced by 3dB for each octave increase in the high pass frequency. To oversimplify, what takes 250w from 40Hz requires only 125w from 80Hz. You don't have to go very high with the crossover frequency before power loss is a moot point compared to insertion loss in dB.
                www.billfitzmaurice.com
                www.billfitzmaurice.info/forum

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                • #9
                  Re: Is 16 ga adequate for an 80 foot speaker run?

                  80 ft of 16 gauge would have about 0.32 ohm DCR for each single wire.
                  http://en.wikipedia.org/wiki/American_wire_gauge
                  Not counting the inductance and other possible effects, you can simulate the effect of 80 ft 16 gauge wire( actually a pair of wires) by using a very short run of speaker wire in series with 0.32 ohm resistor for each wire. If the speaker sounds good to you then it should be all right.

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                  • #10
                    Re: Is 16 ga adequate for an 80 foot speaker run?

                    Originally posted by billfitzmaurice View Post
                    High passing at 80-100Hz may not be major, but it's certainly not irrelevant, as power density is reduced by 3dB for each octave increase in the high pass frequency. To oversimplify, what takes 250w from 40Hz requires only 125w from 80Hz. You don't have to go very high with the crossover frequency before power loss is a moot point compared to insertion loss in dB.
                    Hence the reason I said "this assumes that you're truly pushing 250 watts above your high-pass frequency."

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                    • #11
                      Re: Is 16 ga adequate for an 80 foot speaker run?

                      Thanks guys. I went ahead and got a 14 gauge wire instead.
                      Form does not follow function
                      Form is simultaneous to function

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                      • #12
                        Re: Is 16 ga adequate for an 80 foot speaker run?

                        I can understand wanting to save some money for a long run like that. Generally, I will go over kill. Higher gauge wire has less resistance. While it might not be obvious in a AB comparison, it is measurable.

                        For me, pure copper cable, soldered connections, good quality connectors.

                        I don't expect anyone to believe me, but it could have sworn I've heard a difference going between thin cable and thick cable. At any rate, the price difference isn't much, so I'll just go with what has the least amount of resistance.

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                        • #13
                          Re: Is 16 ga adequate for an 80 foot speaker run?

                          Originally posted by generic View Post
                          ... Generally, I will go over kill. Higher gauge wire has less resistance. ...
                          I'm the same way... I refuse to use 14 AWG in house wiring and will always use 12 AWG.

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                          • #14
                            Re: Is 16 ga adequate for an 80 foot speaker run?

                            The biggest effect is that the increased series resistance of a long high gauge run will add fluctuations to the frequency response of the speaker which are dependent upon the impedance profile of the speaker. This can add a slight midrange hump where the impedance peak is, and also effect the bass tuning.

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                            • #15
                              Re: Is 16 ga adequate for an 80 foot speaker run?

                              Originally posted by jimangie1973 View Post
                              The biggest effect is that the increased series resistance of a long high gauge run will add fluctuations to the frequency response of the speaker which are dependent upon the impedance profile of the speaker. This can add a slight midrange hump where the impedance peak is, and also effect the bass tuning.
                              Unless you're seriously under-gauged there won't be enough resistance to make that much difference; you can find an ohm or more difference in the output impedance of amps, which would have even more effect.
                              I try to avoid more than a 50 foot run, not because of resistance issues, but capacitance and inductance. In pro-sound typically we put the amps as close as possible to the speakers, and let the long cables in the system be the line level sends, as those create fewer issues than long speaker cables. And you can use 22ga.
                              www.billfitzmaurice.com
                              www.billfitzmaurice.info/forum

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