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  • #16
    Originally posted by Navy Guy View Post

    It's funny that you bring this up because I just mentioned in another thread a day or two ago that I would never recommend building this speaker to anyone.
    I can't find anything at all on the speaker. What do you see as a problem with the design? How low will that tweeter cross and sound good? I'm currently using the GFC as a mid in a 3-way. I would normally cross it pretty low, but I'm using a tweeter that can't go real low. It's not finished, and I am just playing around with the design, but it does some things very well already.

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    • #17
      rob - the speaker design is posted over on diyAudio website.
      Dear DIY'ers, Just to let you know I have completed the design on the 2-way LM-1 speakers. The cost to build is around $500/pair with cabinets. It
      Paul

      The "SB's" build page
      http://techtalk.parts-express.com/sh...-4-(pic-heavy)

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      • #18
        Originally posted by rpb View Post
        I have a pair of those woofers! I can help you I believe. Can you post a link to the design, or tell me what parts are on the woofer? By the way, I really like the mids from this woofer.
        A first order filter is not going to get the results you want. A 4th order will work way better, but will cost more.
        Here is the design
        https://speakermakersjourney.blogspo...crossover.html

        I do appreciate the author's time and effort to create the design and write up, but it just sounds way off.

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        • #19
          What are the baffle dimensions, and location of the drivers on the baffle? How close to walls will the speaker be used? What do you want the speaker to do best? (I know, tough question.)

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          • #20
            Originally posted by rpb View Post
            What are the baffle dimensions, and location of the drivers on the baffle? How close to walls will the speaker be used? What do you want the speaker to do best? (I know, tough question.)

            Front baffle is 7.5" wide by 12" tall
            These exact boxes
            https://www.parts-express.com/dayton...herry--302-703

            Both woofer and tweeter are centered on the baffle with the tweeter above the woofer and only about 1/4" between them

            I would be using these on stands, about 5 feet in front of a wall. About 5 feet from side walls too. For listening to music and moderate levels (80 to 90 dB mostly, rarely higher than that). Mostly 80s music and used a small subwoofer (voxel if it sounds reasonable otherwise some sort of 6.5 or 8" subwoofer which I haven't built yet)

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            • #21
              The x-over you currently have does not have enough baffle step compensation for that room placement. You need a couple coils and caps to get the response down where it should be. The x-over, that I would build for a setup like that would be rather large, and a challenge to fit into the box. There's more than one way to do it. Would a 4 ohm load be a problem?



              Do you like the idea of a trial and error approach to getting better sound? You would need some spare parts. I played around with a sim, and I believe you need a .8mH, and 2.5mH coil, a 5 or 6 uf cap, and a 50uf cap, and some additional resistors. I could show you some sims, but they are rough, and woofer only. I'm going on memory and a similar woofer, so these are not exact.

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              • #22
                Originally posted by rpb View Post
                The x-over you currently have does not have enough baffle step compensation for that room placement. You need a couple coils and caps to get the response down where it should be. The x-over, that I would build for a setup like that would be rather large, and a challenge to fit into the box. There's more than one way to do it. Would a 4 ohm load be a problem?



                Do you like the idea of a trial and error approach to getting better sound? You would need some spare parts. I played around with a sim, and I believe you need a .8mH, and 2.5mH coil, a 5 or 6 uf cap, and a 50uf cap, and some additional resistors. I could show you some sims, but they are rough, and woofer only. I'm going on memory and a similar woofer, so these are not exact.
                Thank you, I appreciate the help.

                4 ohm load is ok, and I would like to see any sims that you have.

                Trial and error is ok too. And in this case, may be the best option

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                • #23
                  You can always try this XO - it includes 4-5dB of BSC.

                  264-1012 tweeter HP: 2nd order w/L-pad: 12uF series cap, 0.60mH shunt coil, "L" is SR=3ohms / PR=3ohms (as well) - positive polarity indicated
                  264-1074 woofer LP: 2nd order w/Zobel: 2.5mH low DCR (iron) series coil, 10uF shunt cap (to ground), Zobel = 10ohms + 6uF.

                  Runs around 82dB nearly +/-1dB (over tweeter range). Fc near 1.4kHz. Tweeter range drops below 5ohms (barely), so I can't call it 8ohm "nominal", but I doubt that it would be a hard drive for ANY (vintage - even) 8ohm rated amp. Have fun.

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                  • #24
                    Chris... Try this with your sim, and see if it's close. I'm working with an unknown, but similar frd file at the moment, but this looks promising, and simple.

                    Damped 3rd order on the woofer.
                    1.8mH
                    7uf with a 2 ohm resistor
                    .6mH

                    My current sim shows a nice 4th order at about 2.5k.

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                    • #25
                      2.4mH 8.2uf
                      1.0mH 5.6uf
                      traditional 4th order

                      Measured response on 8.75 x 14 baffle.
                      Attached Files

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                      • #26
                        Raw measurement
                        Attached Files

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                        • #27
                          I made a filter for my tweeter so that I could listen to the speaker. The box is a sealed 3l that has no bass below about 120hz because the box is too small. Not a totally fair way to audition a x-over, but it was handy to use, so I did. I think it might be better with a little more BSC, but for only 4 parts on the woofer, it showed promise. Maybe tonight I'll try it with a sub to see if adding some bass improves the overall tonal balance.

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                          • #28
                            Thank you RPB and Chris

                            I'll use your designs as starting points and go from there.

                            I appreciate the help!

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                            • #29
                              I did some more playing around this evening. This is the GFC woofer with my BC25SC06-04 tweeter. Still needs a little tweaking to smooth things out. X-over point is 3k. Sounds pretty good listening to one speaker with the sub.
                              Attached Files

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                              • #30
                                Looks great. I'm assuming you used the 4th order listed above for the woofer.

                                What did you do for the tweeter?

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