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  • X over help

    Hi I'm attempting to build an "Amiga" style speaker with some drivers I have hanging around. Namely Hi Vi M6n and Peerless XT25BG30

    So far I have this as a potential crossover. I would like any feedback from the esteemed members of the group.

    Please forgive any mistakes I may have made and thanks for your input.

    P
    Attached Files

  • #2
    How did you come up with that XO? Do you have any measurements to use? Or did you use some kind of crossover calculator? Sent from my SGH-I337M using Tapatalk
    https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

    Comment


    • #3
      HI Ryan No measurements just the spec sheets and a couple of different online X over calculators and some guess work. Am I way off the mark ?

      Comment


      • #4
        Well, yes. Online calculators do not take into account the complex impedance and freq resp of the drivers. They assume a fixed resistance in which a speaker is not, save for the ribbon/amt crowd, but I digress.

        I was actually surprised to see your layout. That crossover type is not common. And actually, the complexity isn't really necessary. A simpler parallel network using a 2nd order electrical filter on the woofer and probably 3rd order on the tweeter will work well.
        https://www.facebook.com/Mosaic-Audi...7373763888294/

        Comment


        • #5
          Hi isaeagle4031.

          So you think that the less is more approach is a better solution in this case? Are the L pad and Zobel filters not needed? I'm new to this and won't be able to test the drivers or measure them until I'm home after the tour finishes.

          Perhaps I should buy all the components and just experiment?

          Also BSC should I be concerned about that or again buy the bits and add if they sound like they need it?

          Many thanks again for the input.

          P

          Comment


          • #6
            Originally posted by paulspencer16 View Post
            Hi isaeagle4031.

            So you think that the less is more approach is a better solution in this case? Are the L pad and Zobel filters not needed? I'm new to this and won't be able to test the drivers or measure them until I'm home after the tour finishes.

            Perhaps I should buy all the components and just experiment?

            Also BSC should I be concerned about that or again buy the bits and add if they sound like they need it?

            Many thanks again for the input.

            P
            Less is almost always better. A good rule of the thumb; Use all the parts needed, but only what you need. An Lpad for the tweeter is necessary, but a zobel is not. Any competent design will incorporate the right amount of BSC. But that does not need to be another circuit. BSC can be incorporated into the woofers inductor. The Lpad then is used to attenuate the tweeter to match the woofer.

            Here is an example of a circuit that is very simple in design. It has 6db of BSC, a very flat response, and solid phase tracking over a wide range. 2nd order electrical filters on both drivers came in at 4th order LR slopes for both drivers.
            https://www.facebook.com/Mosaic-Audi...7373763888294/

            Comment


            • #7
              I'd be weary of using those online XO calculators as isaeagle said. Those are common drivers. I wonder if there's an existing design using them or if someone who has used one or both could work something out. I don't have measurements for the woofer but I have the tweeter on a 8x14" baffle. Sent from my SGH-I337M using Tapatalk
              https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

              Comment


              • #8
                Thanks so much for the advice guys I'll go back and have look at the X over again and add some BSC and rejig. Thanks again.

                Comment


                • #9
                  Originally posted by isaeagle4031 View Post
                  Well, yes. Online calculators do not take into account the complex impedance and freq resp of the drivers. They assume a fixed resistance in which a speaker is not, save for the ribbon/amt crowd, but I digress.

                  I was actually surprised to see your layout. That crossover type is not common. And actually, the complexity isn't really necessary. A simpler parallel network using a 2nd order electrical filter on the woofer and probably 3rd order on the tweeter will work well.
                  I think his schematic is a basic parallel crossover, it just looks like a sxo by the layout. I thought it was sxo at first but then realized the center leg was just the ground plane.
                  Projects:

                  transcenD: http://techtalk.parts-express.com/fo...5035-transcend
                  Summits: http://techtalk.parts-express.com/sh...75-The-Summits
                  References: http://techtalk.parts-express.com/sh...-My-References
                  Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

                  Comment


                  • #10
                    The m6n will need the crossover to deal with the cone resonance at about 8.5hkz as well. Either a tank or notch filter.
                    Projects:

                    transcenD: http://techtalk.parts-express.com/fo...5035-transcend
                    Summits: http://techtalk.parts-express.com/sh...75-The-Summits
                    References: http://techtalk.parts-express.com/sh...-My-References
                    Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

                    Comment


                    • #11
                      Originally posted by dynamo View Post

                      I think his schematic is a basic parallel crossover, it just looks like a sxo by the layout. I thought it was sxo at first but then realized the center leg was just the ground plane.
                      By jove, you are right! Guess that's what I get trying to be all techy from a phone lol!
                      https://www.facebook.com/Mosaic-Audi...7373763888294/

                      Comment


                      • #12
                        Hello gentlemen have had a play/think/research and came up with this revision .

                        Any thoughts? I don't have access to ant modellers so would be interested if anyone could test this .

                        Many thanks
                        Attached Files

                        Comment


                        • #13
                          See how your software models this (using YOUR latest iteration as a base):
                          LP (HiVi): Drop the coil down to 2.5mH (use a low DCR "iron-core" - I modeled w/a DCR of 0.4ohms), and the cap to 4uF. This lifts the woofer XO up so much that a "notch" (tank) filter gets to be helpful. All that needs to be is a (tiny) 0.68uF cap across (in parallel with) the coil.
                          HP (XT25): raised cap up to 15uF, and dropped coil to 0.30mH. This changes the shape of the "knee" (or shoulder) of the rolloff. I've effectively raised your Fc from 1.6k to 1.8k - but I'm not sure this tweeter can cross that low (regardless of a rather low Fs). L-pad seems good.

                          Negative polarity is "indicated" on the tweeter. This XO has about +3dB BSC (so had yours).

                          Comment


                          • #14
                            What about the speaker dimensions? Are you using the Amiga cabinet? It would be best if you list everything you're planning or thinking. The devil is in the details!
                            "Everything is nothing without a high sound quality." (Sure Electronics)

                            Comment


                            • #15
                              Hey there thanks for the input guys .

                              Re cabinet ....I'm thinking of using the Amiga cabinet design as a base, yes. I'll probably follow the dimensions to get the correct internal measurements and then construct it from either red oak or walnut with a double thick front baffle and radius all the outside edges. Mount it on brass spikes. I'd also use the flared ports not too sure how much influence that will have?

                              Chris thanks for your ideas on the X over. I'll add the extra cap to the LP side of things. I was aiming to X over to the tweeter @ approx 2k as a start point and see how that sounded in the "real world". I can't run any simulations as I'm Mac based and haven't found anything that will run on my laptop. Can't get PCD to work from Xcel either so its all being done with paper and pen and a couple of online programs. Do you think it would be worth knocking up a test X over and baffle to have a listen or keep working on the x over still?

                              Again many thanks.

                              P

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