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I could really use some help designing 3 way Crossovers

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  • #16
    Thanks mobius, I didn't realize dimensions were needed.

    The baffle is 16.5" wide x 30.5" tall. This is the same as the inside dimensions.
    The interior is 9.5" deep. Volume is 78 liters -bracing - drivers - mid chamber - port = 68 liters

    The woofer is centered 20.5" from the top of the baffle and equidistant from both sides
    The mid is centered 5" from the side and 10.5" from the top of the baffle
    The tweeter is centered 5" from the side and 5.5" from the top of the baffle
    The port is centered 5" from the other side and 10.5" from the top of the baffle

    Is this all that is needed?
    Last edited by clang; 08-09-2020, 01:39 AM.

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    • #17
      Originally posted by clang View Post
      Thanks Again Gents, I didn't mean for this thread to become a fight.

      A little more about the use of these speakers -I'm planning on using them in the basement rec room/bar. It will NOT be a Maxell Man situation where I plan in sitting in one perfectly positioned chair and expect to recreate a symphony in front of me. I'll probably have a second pair of smaller speakers on the far side of the room by the bar to more evenly fill the room with background music when needed. The second pair of speakers are JBL 4401 Control Monitors from the mid-80s.

      Music preference is mostly studio albums, rock up to grunge and alternative. Some Jazz and bluegrass and oldies. Some live stuff, but not my primary focus. If I had a choice between imaging and detail, I'd probably take detail. I don't expect to close my eyes and imagine a perfect stage in front of me.

      The music sources are a CD player, tablet or phone, and occasionally I pull out my old turntable for nostalgic reasons.

      My current amp is a Technics SU-V707 Integrated Amp from the mid-80s. I think its 85 watts/channel and handles 4-16 ohm. I prefer 8 ohm speakers since I believe they are easier on the amp. Other amps, receivers of varying vintages and power make the rotation, but most of the stuff is 80s-90s vintage. (I'm probably dating myself with my preferences).

      I do not run a sub-woofer, so good base from the speakers is important. My gold standard target sound would be those old JBL 4312 Control Monitors I mention in my first post, but to be honest, I'd be completely happy if they sounded something like an old pair of Cerwin Vega D5s my brother has. Think 1980s-1990s 3-way monkey coffins - that's the sound I'm hoping for.
      It's not uncommon for a 3-way to have a low impedance. My sim does, and the one in post #4 does as well. My sim isn't posted yet, and might not be suitable.

      Do you have tone controls that can boost the mid-range? The mid in my sim is not padded, and is barely keeping up with the woofer. If it was padded, the impedance might would come up a little.

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      • #18
        My current amp does not have a mid control, but I've got an old Realistic receiver handy that does.

        I don't mind a little base heavy, I can always turn it down.

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        • #19
          Check this out....
          Click image for larger version  Name:	wild thing.jpg Views:	0 Size:	250.2 KB ID:	1447715

          Now before anyone has a hissy about this xo, I'm only posting the results for entertainment value. Hmmm.... woofer crossed to the mid below 200hz ??? Probably not a good idea to build this one, as you might burn down your house or something if you are not real careful with some things. Safe to say that this would be considered a 4 ohm speaker! That said, in my thinking, the mid handles all of the vocals, so being high or low relative to the speaker should be less of a problem. The tweeter should be safe crossed this high, although doing so smoothly takes some effort due to a pesky bump in the mids response. My "other filter" is very similar to the one already posted, so Chris hates it. I've not used this tweeter, so better wait for a filter from Chris. He likes theses DC drivers, and knows their limitations better than me.. I tend to use Morels, Peerless, and some RS series.

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          • #20
            I thought you guys would post some filters by now.

            Still playing around, although this one would be safe.Might not be representative of a real world xo though. Nothing beats being able to measure.

            Click image for larger version

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            • #21
              Thanks rpb, I wanted to let you know that I've also gotten a few designs via PM. Since this is a learning experience for me, I'm probably going to try out at least a couple of them to see the differences between them.

              What the heck, it's only time and money...

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              • #22
                Originally posted by clang View Post
                Thanks rpb, I wanted to let you know that I've also gotten a few designs via PM. Since this is a learning experience for me, I'm probably going to try out at least a couple of them to see the differences between them.

                What the heck, it's only time and money...
                I figured someone would go the pm route. No surprise. Hope it works out for you.

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                • #23
                  Originally posted by rpb View Post
                  I figured someone would go the pm route. No surprise. Hope it works out for you.
                  Doesn't really help the rest of the community learn anything though does it? Perhaps they are just afraid of having their suggestions mercilessly shot down in a barrage of personal attacks! lol....
                  Last edited by DeZZar; 08-09-2020, 08:49 PM. Reason: Spelling...

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                  • #24
                    Actually gents, I reached out to one person for their input and I also received 2 other unsolicited designs. I now have a range of plans from a simple 1st order crossover to a 13 element design. I'm going to try at least a couple of them over the several weeks and will let everyone know what I think (if a complete noobs opinion is worth anything). FWIW, I will probably start with the simplest crossovers first, I mean they worked for several manufacturers 30 years ago, so why not now?

                    Being new to this forum, I appreciate the knowledge that people are willing to share. I just wish we could be a little bit kinder and respectful to each other. Sometimes what you write isn't what you meant to say, or at least isn't how you meant to say it. Maybe it's a good time to take a reset and look more positively at each other's contributions. The future of this forum is what you make it.

                    Thanks Again for your interest and support.

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                    • #25
                      Hi Gents,

                      I built my first crossovers based on a very simple first order design I received from a forum member:



                      I really need more practice on my soldering skills...

                      The design crosses over at 920 Hz and 3,900 Hz. More like an old school speaker designs from the 70s and 80s:
                      Click image for larger version  Name:	70s rockfan XO.jpg Views:	0 Size:	29.6 KB ID:	1449485

                      They sound pretty darn good, but there is an issue I think I am going to try to improve. Some female vocals sound a little washed out or thin. It's not terrible, but it is noticeable in songs like "Best of my Love " by the Emotions. I can also hear it in Ceelo's "F-You" - the backup singers are subdued. These are just a couple of examples, I hear it in other songs too.

                      The model of this crossover shows a dip around 2,200 Hz:



                      I think it might be related to something another forum member brought up about the Dayton Speakers. He recommended a notch filter to avoid some problems with the speakers I chose. I'm thinking about updating the Xover by adding a notch filter like this:


                      It levels out the dip in the model. It's not perfect but it looks like an improvement:


                      Aside from that, I might have a little too much base, but that might change if I can improve the dip in the midrange. The base is not terrible, I just turn down the base dial -2 or -3dB on the receiver when the volume is cranking and it is good to go. At lower volumes I leave the controls flat.

                      So watcha think???


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                      • #26
                        I think you know what I think.

                        Did you model that 12" woofer w/a 0.27mH coil on it?
                        The coil "rolls" it off about 1/4dB @ 2kHz, and about -1dB @ 5k. That coil on there is a complete waste of money. It's useless. (Sorry to anyone I've offended.)

                        (Did you mean a 1.27mH coil, on the 12"?)

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                        • #27
                          Induction coils were reversed. Here it is corrected:

                          Click image for larger version

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                          I'll post other suggested designs soon for comment.

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                          • #28
                            The only part doing much work in that XO is the 22uF cap (and the 4uF on the tweeter, for some part).
                            The bottom of the 5" IS being rolled off, but the top mostly isn't.
                            The 1.5mH coil on the woofer is only pulling its output down by -4dB from 2-4k. Mostly ineffectual.

                            Between the 2k peak (breakup) on the 12" and the 4k peak on the 5", the midrange is running 8dB hotter than the tweeter (above 5kHz) and the woofer, down around 300-600, and yet, there IS a -4dB "hole" around 2.5k.

                            If you Zobeled the woofers (7n(ohm)+16uF on the 5", and 8n+47uF on the 12"), and added 8n(ohms) series resistance to the mid, things would at least end up near the same level (88dB +/-3-4dB). Still a mess.

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                            • #29
                              Originally posted by clang View Post

                              So watcha think???

                              I think you will like the next xo better.

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                              • #30
                                Originally posted by rpb View Post

                                I think you will like the next xo better.
                                I'm working on it. I'm learning a lot too.


                                Here's another submission:


                                And here is the frequency response:
                                Click image for larger version  Name:	CR Fr Res.jpg Views:	0 Size:	72.7 KB ID:	1449828
                                Attached Files

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