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(Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

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  • (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

    fEarful 12 Subs. A Peavey IPR-3000 DSP can serve as active crossover, parametric EQ and power amp -- 280 W available for each line array and 400 W available for each sub. Crossover frequency can be in the 125 - 150 Hz range.

    SPL for 18 drivers ≈ 77.5 + 10 log (18) ≈ 77.5 + 12.5 ≈ 90.0 dB. With 500 Watts input this equates to 117 dB.

    SPL for each bass cabinet ≈ 90 dB. With 400 Watts input this equates to 116 dB. Two cabinets side by side with 800 watts total input would be capable of 122 dB maximum output.

    Thoughts, suggestions and comments will be welcomed. Thanks!

    :bassist:
    Attached Files
    Last edited by :bassist:; 01-17-2012, 04:22 PM. Reason: Forgot to include the driver details

  • #2
    Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

    Originally posted by :bassist: View Post
    fEarful 12 Subs. A Peavey IPR-3000 DSP can serve as active crossover, parametric EQ and power amp -- 280 W available for each line array and 400 W available for each sub. Crossover frequency can be in the 125 - 150 Hz range.

    SPL for 18 drivers ≈ 77.5 + 10 log (18) ≈ 77.5 + 12.5 ≈ 90.0 dB. With 500 Watts input this equates to 117 dB.

    SPL for each bass cabinet ≈ 90 dB. With 400 Watts input this equates to 116 dB. Two cabinets side by side with 800 watts total input would be capable of 122 dB maximum output.
    Cool idea, would love to see it done.

    What driver is that in the arrays?

    You might find the top end giving up above 12K or so depending on the driver, but for many applications it would be fine.

    Step up to the 15 inch subs, those twelves will most likely be displacement limited below the calculated SPL, and there is no advantage to using a smaller driver here, as weight will not increase by very much. Crossing over as high as you would need to, you would want to keep the woofers with the arrays, so think about incorporating a mounting system. That would give you the stability you will need, without adding pieces to carry!

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    • #3
      Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

      Thanks for the reply AMC. I went back and edited the thread title to include the driver info.

      I really like the fEarful concept for bass cabinets. I have a 1 x 15" cabinet based on the fEarful 15/6 -- described in this post.

      The fEarful 15 Sub would be nice with these line array stacks too. Thanks for the suggestion!

      :bassist:

      Comment


      • #4
        Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

        I only see two problems...

        That fEARful 15 cab is to small to give you any real benefit from the 12, in order to fully utilize the 15 it would need a cab about twice as big. Remember those cabs were designed to play your bass through, not for sub duty in spite of the name.

        And then there is the PRICE!

        But I bet it would sound nice. Some people have done some work of some 'shaping' of these small drivers, incorporate that perhaps, and it would turn in to a fantastic sounding system. I would also bet that with a little help, those ND91s could get down to around 90Hz without risking any damage. Would increase placement options.

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        • #5
          Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

          Originally posted by :bassist: View Post

          Thoughts, suggestions and comments will be welcomed. Thanks!

          :bassist:
          One of the 'fail factors' of the LI is that you don't want to place subs and mains in the same footprint. Subs should take advantage of wall loading whenever possible, and should seldom be split left/right. Another is that the line should be mounted as high as possible throw over the heads of the audience close in, a third is that no midbass will go as low as you need, 100-125 Hz, and still have good dispersion above 8kHz at best. Separate lines of midbasses and tweeters are a must. In short, the Bose is not worthy of being copied, so don't.
          www.billfitzmaurice.com
          www.billfitzmaurice.info/forum

          Comment


          • #6
            Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

            What about a driver like the W4-1052SDF? It plots well from 100Hz to 15KHz. I know it's a bit larger and I'm not real good with the concepts of line arrays as far as center to center spacing, etc. but it seems like a decent candidate from what little I know.

            Comment


            • #7
              Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

              Originally posted by :bassist: View Post
              fEarful 12 Subs. A Peavey IPR-3000 DSP can serve as active crossover, parametric EQ and power amp -- 280 W available for each line array and 400 W available for each sub. Crossover frequency can be in the 125 - 150 Hz range.

              SPL for 18 drivers ≈ 77.5 + 10 log (18) ≈ 77.5 + 12.5 ≈ 90.0 dB. With 500 Watts input this equates to 117 dB.

              SPL for each bass cabinet ≈ 90 dB. With 400 Watts input this equates to 116 dB. Two cabinets side by side with 800 watts total input would be capable of 122 dB maximum output.

              Thoughts, suggestions and comments will be welcomed. Thanks!

              :bassist:
              I figure 116dB per 9-driver box at full rated power (270w), 8 ohm load.
              Two boxes parallelled would yield 122dB at 4 ohms.

              Comment


              • #8
                Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

                Originally posted by jcpahman77 View Post
                What about a driver like the W4-1052SDF? It plots well from 100Hz to 15KHz.
                Off axis?
                www.billfitzmaurice.com
                www.billfitzmaurice.info/forum

                Comment


                • #9
                  Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

                  Originally posted by billfitzmaurice View Post
                  In short, the Bose is not worthy of being copied, so don't.
                  Copied, no, Improved upon, YES!

                  The bose offers a nice form-factor (similar to WAF) and people who use it love it. There are always trade offs, with any system, doesn't mean it's bad, just different.

                  I do wonder if the second set of 9 drivers would even be necessary, your not really gaining that much, and it would double the weight and size, and only having one would make it easier to get up high. As far as tweeters go, for what these types of systems are mostly used for, I don't know how necessary it would be. Could always add a side mounted tweeter array for times when it's needed. Maybe 9 ND20's or ND16's. Incorporate something like this and it would also become very easy to use. http://www.parts-express.com/pe/show...number=300-797

                  Comment


                  • #10
                    Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

                    Originally posted by billfitzmaurice View Post
                    Off axis?
                    I haven't seen any plots, but this is frequently recommended for car audio which is almost all off axis so I'm inclined to believe it does well in that respect.

                    Comment


                    • #11
                      Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

                      Good discussion -- thank you again to AMC and thanks to Chris, JC and BFM. Bill, I have a first edition of your Speaker Builder's Loudspeakers for Musicians book and I really appreciate your contributions to this hobby and this thread. I have been trying to pay attention in class -- in the first post I did mention placing the two LF cabinets side by side

                      I would like to read what John Murphy and Jim Griffin have to say about this system. It was the MCLA project that led me to the ND91-8 driver. I didn't want to hijack the MCLA thread...

                      :bassist:

                      Comment


                      • #12
                        Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

                        Originally posted by jcpahman77 View Post
                        What about a driver like the W4-1052SDF? It plots well from 100Hz to 15KHz. I know it's a bit larger and I'm not real good with the concepts of line arrays as far as center to center spacing, etc. but it seems like a decent candidate from what little I know.
                        I would worry about the weight of 18 of those per side, did you see the magnets? Very impressive otherwise.

                        But yes, they will likely start beaming at about 6 to 8K.

                        Comment


                        • #13
                          Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

                          Originally posted by jcpahman77 View Post
                          I haven't seen any plots
                          A driver will beam above the frequency where the cone is a wavelength in diameter. Do the math. And don't follow the Bose example. They don't go 2 way because it's the best option, they do it because it's the cheapest option.
                          www.billfitzmaurice.com
                          www.billfitzmaurice.info/forum

                          Comment


                          • #14
                            Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

                            Originally posted by AMC View Post
                            I would worry about the weight of 18 of those per side, did you see the magnets? Very impressive otherwise.

                            But yes, they will likely start beaming at about 6 to 8K.
                            They make a neodymium version which specs out about the same but is a bit more expensive.

                            Originally posted by billfitzmaurice View Post
                            A driver will beam above the frequency where the cone is a wavelength in diameter. Do the math. And don't follow the Bose example. They don't go 2 way because it's the best option, they do it because it's the cheapest option.
                            It's been some years but IIRC you calculate the length of a frequency as 1/freq right? Not sure what that means for a 4" driver though lol

                            Comment


                            • #15
                              Re: (Yet another) line array concept -- Dayton ND91-8 (36 of 'em!)

                              I don't want to be too negative here but since this is the pro audio forum and this is supposedly a pro audio project I'd have to suggest that it's missing the mark by at least 10db in sensitivity. In other words.. if a speaker system doesn't produce upwards of 100db with 1w input then it isn't much more than a large home audio speaker... which is exactly what I consider the Bose L1 system to be. That system does a very good job of throwing cocktail hour sound levels over a wide area but that's about it, it can't generate rock band type levels. Now.. that may be fine for the OP's intended use so I'm just saying more than anything, and taking the amplifier and controls out of the array base and putting them in a rack is a big improvement over the L1 setup, but besides that and the superior sub modules I don't see this design as significantly better than the L1. If you want to outclass the L1 in all respects you would build something that looks something like Bill's SLA or the SLS8695, both two way mains with dedicated tweeters.

                              http://www.nczon.com/LS8695V2.htm
                              Paul O

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