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Introducing: Echelon

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  • Introducing: Echelon

    Introducing: Echelon
    Echelon


    Support

    Dave Pellegrene and Dan PoinsettJeff Bagby for directing me to the close-out source for the woofers a couple years back. Ben (Wolf) Shaffer suggested the names, Echelon for the WMT and Echelon Fortissimo for the upcoming WMTM version. Thanks to others for their name suggestions as well. Thanks to all the kind comments in regard to these speakers at the InDIYana event. They are very much appreciated.


    Concept




    The Drivers: Echelon (WMT version)






    The woofer can handle over 500 watts of power and still not reach excursion limits. This power handling capability will be important for the WMTM version. In a sealed box, this woofer is capable of keeping up with the fast transient response of the open back planar mid without any detectable differences in the character of the sound through the crossover.


    Midrange: BG Neo10 planar
    The neo10 is the latest large format planar driver from Bohlender and Graebener. It has been designed to increase power handling, low end performance and sensitivity over previous models, while keeping distortion low and maintaining great transient response. Impedance measures close to flat across the entire spectrum, at about 6.5 ohms.

    These are placed in an open back configuration which allows for some adjustment of midrange energy as desired. The open back configuration provides a substantial increase in soundstage width and depth, at no apparent loss of imaging

    Tweeter: Transducer Lab N26C
    The N26C is a high purity, molded Al2O3 Alumina ceramic dome tweeter, designed / assembled / tested in the USA, utilizing CNC machined metal parts, a double magnet design, decompression chambers, a fiberglass-under-hung voice coil (1mm linear excursion), silver terminals, with a response range of 950hz - 45khz. They are sold in pairs that are frequency matched to +/- 0.75db.

    http://www.transducerlab.com/6501/6522.html



    In addition, the waveguide provides controlled directivity of tweeter and matched directivity with the midrange at the crossover point. This ensures an improved power response over traditional flush mounted tweeters and a speaker that is less sensitive to room placement.




    I will post more on the crossover design and box construction next. When I have more time, I will add crossover detail and sumlation as well as some build pics. It took a lot longer to write this up than expected!
    Attached Files
    Dan N.

  • #2
    Re: Introducing: Echelon

    Crossover Design

    The woofer was surface mounted, the midrange rear mounted and the tweeter waveguide mounted. Combined with the sloping baffle, this allows for the driver voice coils to be equidistant to the listener’s ear, which promotes improved phase tracking between the drivers over a wider range of frequencies and reduces or eliminates the need for asymmetric crossover slopes.

    Crossover points are at 325hz and 2100hz. The Woofer to midrange acoustic slopes are approximately 15db/octave, halfway between second and third order. The midranges to tweeter acoustic slopes are approximately 24db/octave. The crossover models at +-1db from 40hz to 14khz, where the tweeter begins to roll off in the upper half-octave (see simulated response graph). The woofer is wired in reverse polarity.

    Due to the increased rear radiation of the open back mid, the midrange is very slightly depressed in the crossover design. However, the relative level of the mid is somewhat adjustable to fit an individual’s sound or musical tastes, room response or speaker placement by altering the amount of stuffing in the open back enclosure. A number of different materials where tested in the open back, but the most effective I found was one layer of 2”unbacked fiberglass insulation along the bottom, with poly-fill being employed if further attenuation is desired. I intend to test the recycled denim based insulation material as a replacement for the fiberglass.

    Two pair of binding posts are provided on the rear of the cabinet. This will allow for bi-amping of the Woofer and Midrange/Tweeter crossover separately, which will be necessary for the Echelon Fortissimo, where the woofer will be controlled by an active XO, such as the MiniDSP. Bi-amping of the passive XO may also offer some benefits.



    Woofer/mid Box Construction

    The woofer box is constructed using MDO plywood. This plywood has a thin layer of MDF-like material on the outside layer that does not chip out or splinter when cut and makes it easier to paint or veneer than other plywood’s. It is also much lighter than MDF. The joints around the sides and top are all miter joints, so there is no telegraphing of the joints through the paint. The rear panel is dado’d into the sides and a layer of 10 mil paper back veneer was added over the back to reduce telegraphing.





    The sealed portion of the woofer box is heavily stuffed throughout, which helps absorb the sound that radiates from the rear of the woofer cone and flattens the low end response. The woofer was surface mounted, rather than flush or rear mounted for a couple of reasons, as mentioned, one of which was visual. The woofer appears larger and more substantial when front mounted and visually attenuates the width of the baffle.

    The many angles to the cabinet sides are for more than aesthetic reasons. They reduce the effect of diffraction and allow the speakers mass to be located near the floor where it is less visually intrusive in the room. Further, none of the cabinet sides are parallel except the top and bottom, which when combined with stuffing reduces or eliminates standing waves inside the cabinet, ensuring that only the drivers are heard, not the box.

    By mounting the woofer near the floor, the woofer’s floor bounce null, experienced at the listening position, is pushed much higher in frequency, well above the crossover point and into the stop band of the woofer.




    Tweeter Box Construction





    The woofer crossover and mid/tweeter crossover are housed on separate boards that are screwed to the top of the woofer/mid box through the rubber tile. There are openings cut in the bottom piece of the tweeter box to allow it to fit over the crossovers. The baffles on both the woofer/mid box and the tweeter box have large facets to further reduce the effect of diffraction.
    Last edited by dlneubec; 04-23-2012, 06:59 AM.
    Dan N.

    Comment


    • #3
      Re: Introducing: Echelon

      Construction Continued

      A number of folks asked about the legs/feet at InDIYana and CJD mentioned them in his post. Here is some info on the legs/feet. I will add a close up photo when I get a chance.

      Legs/Feet

      http://www.8020.net/

      The feet were ordered on Ebay from a company called SimplyPhysics. Here is the site: http://www.simphys.com/Pages/isolation%20products.html

      Last edited by dlneubec; 04-23-2012, 06:54 AM.
      Dan N.

      Comment


      • #4
        Re: Introducing: Echelon

        Crossover Results/Design SimulationsModeled frequency response:Electrical Transfer Function:


        Modeled impedance/impedance phase: based upon in box impedance measurements. Impedance drops below 4ohms briefly at the low end and generally stays between 4 and 9 ohms. Impedance compensation was included in the crossover design to flatten impedance and impedance phase.


        Acoustic phase:


        Group Delay: This is the result of electrical and acoustic delay. I can also post electrical delay if anyone wants to see it.


        Box Model: The box model simulation below includes the effect of room and boundary gain.
        Last edited by dlneubec; 04-23-2012, 08:07 AM.
        Dan N.

        Comment


        • #5
          Re: Introducing: Echelon

          I really like what you've done for the feet. And the baffle.

          Wish I could have made it and heard these!
          diVine Audio

          Comment


          • #6
            Re: Introducing: Echelon

            You missed a real treat cjd. These were amazing! I honestly can not say there was anything about them that I did not like. The bass was powerful without being overbearing.

            Beautiful work Dan! You are an inspiration to the rest of us!
            https://www.facebook.com/Mosaic-Audi...7373763888294/

            Comment


            • #7
              Re: Introducing: Echelon

              Very nice write-up. And exceptional speakers. For those that haven't heard them - they sound as good as they look.

              Jeff
              Click here for Jeff Bagby's Loudspeaker Design Software

              Comment


              • #8
                Re: Introducing: Echelon

                I wish I could have heard those too - another reminder that I need to make a point to get to InDIYana one of these years. The cabinet work looks fantastic and I'm sure based on your skills and the driver compliment that they sound great.

                I have a pair of TC sounds Epic 10's squirreled away for a future project and have always liked the planar BG mids - they are spooky with their realism and detail at times. I used the TC-1000 10's in a 3-way a number of years ago after hearing them in the Salk HT-3. They are as clean and authoritative as anything I've ever heard from 20 Hz to 300 Hz.

                I will definitely have to at some point try out the Transducer labs tweeters - I spent a couple of years developing a ceramic injection molding process for a different application. Given the various choices, I would consider making them out of something other than alumina, though...
                Keep an open mind, but don't let your brain fall out.

                Sehlin Sound Solutions

                Comment


                • #9
                  Re: Introducing: Echelon

                  Wow! That made my heart race! Great work!

                  Comment


                  • #10
                    Re: Introducing: Echelon

                    Now that is bracing!!! Thanks for the recognition on the name, and it does suit very nicely.

                    Looking forward to more pictures of the innards in the top for the xovers.
                    Later,
                    Wolf
                    "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                    "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                    "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                    "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                    *InDIYana event website*

                    Photobucket pages:
                    http://photobucket.com/Wolf-Speakers_and_more

                    My blog/writeups/thoughts here at PE:
                    http://techtalk.parts-express.com/blog.php?u=4102

                    Comment


                    • #11
                      Re: Introducing: Echelon

                      Hi Dan,

                      That is a beautiful speaker! I hope I get to hear it at this falls Iowa DIY event.

                      Jim

                      Comment


                      • #12
                        Re: Introducing: Echelon

                        Those look amazing. You must have a brace every 4-6 inches :eek:
                        :blues: Flat frequency response, a smooth sound power response free of resonance, careful driver-integration, and high dynamic range both upward and downward :blues:

                        Comment


                        • #13
                          Re: Introducing: Echelon

                          Amazing job Dan.....WOW!

                          I want to try the Neo10 in a dipole MTM soooooo badly.

                          Comment


                          • #14
                            Re: Introducing: Echelon

                            Wow! Can I get a pair in Cadillac pearl white?
                            My modest builds:
                            Armadillo TM, A.K.A. Lil' Dillo
                            Tarkus/Armadillo build #2
                            Armadillo Center Channel
                            Au-Rock-O Sub
                            Tarkus
                            Staining MDF tutorial

                            Comment


                            • #15
                              Re: Introducing: Echelon

                              Simply amazing wood work, ambitious audio design, and flawless execution. Sadly, my skills will never be up to the build. Gives me something to aspire to, though.

                              I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
                              "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

                              High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
                              SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
                              My Voxel min sub Yet-another-Voxel-build

                              Tangband W6-sub

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