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  • The Hypothetical's

    Ok first off, hello everyone. I have decided to join the forums in the hopes of taking in all the knowledge i can. I am currently working on a possible design, and i would love to have peoples thoughts and opinions about it. This is the reason i have decided to call them the hypothetical's, because as of right now. It is just a design i am considering, until i have to means to put it all together. my current idea is to put these two drivers together, in a sealed box.

    The tweeter: Vifa BC25SC06-04 https://www.parts-express.com/peerle...eter--264-1028 (I already have two of these.)
    The woofer: HiVi F5 https://www.parts-express.com/hivi-f...range--297-435 (I do not own these)

    My current thoughts are a 3000Hz XO, and based off my image included. I did use online calculators (yes i know, not ideal). Any help with the crossover would be absolutely appreciated. And if you can tell me why something is wrong, i will happily love to know why. The driver choices were based on, i already had the tweeters and the woofer (admittedly based on another build of the same materials and smaller) should sound good. But hey, this is my first serious poke at it.
    Attached Files

  • #2
    As you said, the on-line calculators are not ideal. As such, there really is nothing to be gained by using them other than a very basic understanding of filter orders from an electrical standpoint.

    Since you want to learn and not just have someone design a crossover for you, I would recommend you read Paul Carmody's page on simulated design here https://sites.google.com/site/undefinition/diy

    A quick glance of your proposed crossover shows a few things. First, the woofer has no baffle step compensation. Without this, the speaker will seem to lack bass and sound "thin". The values from an on-line calculator assume the impedance is a set value ie 8 or 4 ohm. It's not. Those are nominal values based on the drivers resistance. Impedance will vary with frequency and the addition of the lpad will effect this as well.

    Accurate measurements or simulated data that includes the effect of the baffle, bass tuning, driver offsets, and phase are necessary for a well designed crossover.

    Please don't be discouraged by my post. It's not intended that way, but to help you on a more productive learning path. Welcome to our insanity!
    https://www.facebook.com/Mosaic-Audi...7373763888294/

    Comment


    • #3
      I love the name. Most of my designs could have that same name

      I also recommend learning a bit about simulation to get the results improved. Those drivers have decent manufacture spec sheets to start from, though I think I've heard that HiVi tends to be hit or miss with their specs. I have an online tutorial for tracing graphs and running simulations as well: http://woggmusic.com/advanced-speake...gn-simulation/

      There's another dude on here, altoid I believe, that created a whole video series published on YouTube on the subject.

      I'll also add that you shouldn't be discouraged. The absolute worst case with your online calculated values is that your frequency response will be a bit wonky. Most people won't even notice, just the nerds that hang out here and have heard what "flat" should sound like on a regular basis. I say build it, and construct your cabinet so you can open it up and swap out crossovers. Then keep learning and the next thing you know you'll have a bunch of tools, crossover parts, and measurement gear. Those are good drivers to build from, and with some tweaks you'll have a really nice speaker.
      Electronics engineer, woofer enthusiast, and musician.
      Wogg Music

      Comment


      • #4
        “Nerds” now, the other day someone referred to the “hive” around here. Interesting trend.
        Don't listen to me - I have not sold any $150,000 speakers.

        Comment


        • #5
          Originally posted by johnnyrichards View Post
          “Nerds” now, the other day someone referred to the “hive” around here. Interesting trend.
          Both of those were me... not cool? Not trying to offend anyone, just acknowledging us as a group of folks super passionate about our hobby and a good group resource for info.
          Electronics engineer, woofer enthusiast, and musician.
          Wogg Music

          Comment


          • #6
            Originally posted by johnnyrichards View Post
            “Nerds” now, the other day someone referred to the “hive” around here. Interesting trend.
            Did you read the post referring to most of us as "mooks? Something like "Any mook with the tools can design an XO. Baffle design is the leading edge."

            Comment


            • #7
              Originally posted by wogg View Post
              I love the name. Most of my designs could have that same name
              I'll also add that you shouldn't be discouraged. The absolute worst case with your online calculated values is that your frequency response will be a bit wonky. Most people won't even notice, just the nerds that hang out here and have heard what "flat" should sound like on a regular basis. I say build it, and construct your cabinet so you can open it up and swap out crossovers. Then keep learning and the next thing you know you'll have a bunch of tools, crossover parts, and measurement gear. Those are good drivers to build from, and with some tweaks you'll have a really nice speaker.
              Woog's approach is a good way to start. I would add that you should run the XO design past here to get some baffle step compensation. Without BSC, you will likely be short on bass. And most everyone (Nerds and all) will hear that and can be disappointed by the outcome. And you'll need some padding on the tweeter lest it is much louder than the woofer.

              Comment


              • #8
                Originally posted by johnnyrichards View Post
                “Nerds” now, the other day someone referred to the “hive” around here. Interesting trend.

                Comment


                • #9
                  Before learning XO design, have you done any box simulations on that F5? Looks like it might get to 60Hz (not too low) in 0.25cu.ft. (pretty small box though).
                  Something like the FREE WinISD ( www.linearteam.org ) works well. Nice tweeter. Thinkin' THAT one might be OK run down to 2.5k ??

                  Don't overlook any of the Dayton 5" to 6" drivers. All pretty good. Mostly cheaper than that F5, most will go lower. I'd look for more than 2.7mm of Xmax.

                  Comment


                  • #10
                    Originally posted by wogg View Post
                    I love the name. Most of my designs could have that same name

                    I also recommend learning a bit about simulation to get the results improved. Those drivers have decent manufacture spec sheets to start from, though I think I've heard that HiVi tends to be hit or miss with their specs. I have an online tutorial for tracing graphs and running simulations as well: http://woggmusic.com/advanced-speake...gn-simulation/

                    There's another dude on here, altoid I believe, that created a whole video series published on YouTube on the subject.

                    I'll also add that you shouldn't be discouraged. The absolute worst case with your online calculated values is that your frequency response will be a bit wonky. Most people won't even notice, just the nerds that hang out here and have heard what "flat" should sound like on a regular basis. I say build it, and construct your cabinet so you can open it up and swap out crossovers. Then keep learning and the next thing you know you'll have a bunch of tools, crossover parts, and measurement gear. Those are good drivers to build from, and with some tweaks you'll have a really nice speaker.

                    Wogg, i went through your page and it seems as though SPL Copy is no longer available. I did try playing with SPL Trace but that did not go so well. Is there any other place i might be able to find it. Googling didn't really net me anything here.

                    Comment


                    • #11
                      Try fprawn's tracer:
                      http://labs.fprawn.com/

                      It rocks!
                      Wolf

                      PS- I think we're more geeky than nerdy here... Nope- not same thing...
                      "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


                      • #12
                        What's the difference between spl copy and spl tracer? Tracer can be a pain to keep on path, but so far it's worked ok. Is fprawn's tracer that much better?

                        ... and great name.
                        http://techtalk.parts-express.com/fo...khanspires-but
                        http://techtalk.parts-express.com/fo...pico-neo-build
                        http://techtalk.parts-express.com/fo...ensation-build

                        Comment


                        • #13
                          Originally posted by Kornbread View Post
                          What's the difference between spl copy and spl tracer? Tracer can be a pain to keep on path, but so far it's worked ok. Is fprawn's tracer that much better?

                          ... and great name.
                          I've only used fprawn's tracer. It usually picks up the correct trace on the 1st time, at most several attempts with some prudent positioning.

                          I don't get it, "Great Name".

                          Comment


                          • #14
                            fprawn is the PETT member's screen-name. I don't get what Kornbread means either.

                            It's easier to use, you can see the plotted points it sampled, and it's easy to use. I mean- EASY!
                            You might have to overlay a color on it if the plot and background are the same color and get the tracer to take, but that's easy too.

                            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


                            • #15
                              Originally posted by Millstonemike View Post


                              I don't get it, "Great Name".
                              ​name of the speaker
                              Paper Towers
                              RS180P/28F surrounds
                              Boombox

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