Announcement

Collapse
No announcement yet.

The Joudas project

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #76
    Originally posted by Wolf View Post
    Your acoustic phase alignment with this xover is not so good.

    Wolf
    Thanks Wolf, how about this one?

    Click image for larger version

Name:	Screenshot 2020-09-13 162827.jpg
Views:	98
Size:	307.9 KB
ID:	1451153 Click image for larger version

Name:	Screenshot 2020-09-13 162750.jpg
Views:	97
Size:	52.0 KB
ID:	1451154

    Comment


    • #77
      Originally posted by rpb View Post
      I think maybe the wave-guide is affecting the woofer response. You can compare factor data maybe and see, or place something over the wave-guide, and remeasure.
      With the sealed box response I posted above, the woofer is in a completely separate box from the waveguide. The response looks weird to me too... I don't know how to make it look not weird though.

      Comment


      • #78
        Originally posted by trevordj View Post

        With the sealed box response I posted above, the woofer is in a completely separate box from the waveguide. The response looks weird to me too... I don't know how to make it look not weird though.
        I just looked at PE measurements, and it appears to be the woofer.

        It would take more parts, but sometimes adding a notch makes things easier. Not always though. On the woofer... Try a notch using 2mH, 40uf, and about 10 ohms, in series with each other, and across the woofer terminals. Part values are WAG starting point. Experiment! Might be a waste of time though. Center the notch around 1k. The rest of the woofer xo will need to be changed a lot with the added notch.

        Comment


        • #79
          Originally posted by rpb View Post

          I just looked at PE measurements, and it appears to be the woofer.

          It would take more parts, but sometimes adding a notch makes things easier. Not always though. On the woofer... Try a notch using 2mH, 40uf, and about 10 ohms, in series with each other, and across the woofer terminals. Part values are WAG starting point. Experiment! Might be a waste of time though. Center the notch around 1k. The rest of the woofer xo will need to be changed a lot with the added notch.
          Alright, I messed with it a bit, how does this look? How much phase alignment should there be at the crossover point? Also, should I be worried about that on axis rise in output above 10k on axis?

          Click image for larger version

Name:	Screenshot 2020-09-13 181216.jpg
Views:	96
Size:	310.4 KB
ID:	1451162

          Click image for larger version

Name:	Screenshot 2020-09-13 181140.jpg
Views:	95
Size:	50.4 KB
ID:	1451163

          Comment


          • #80
            Getting tough for suggestions. Here's a WAG. Just think of it as practice. I may be barking up the wrong tree. Add a 2 ohm resistor in series with the 20.8uf cap. See if that will soften the shape of the woofer roll-off a little. Or.. try a 3rd order filter on the tweeter. I'm guessing, so...?

            Comment


            • #81
              Originally posted by rpb View Post
              Getting tough for suggestions. Here's a WAG. Just think of it as practice. I may be barking up the wrong tree. Add a 2 ohm resistor in series with the 20.8uf cap. See if that will soften the shape of the woofer roll-off a little. Or.. try a 3rd order filter on the tweeter. I'm guessing, so...?
              I’ll keep playing with it.

              I put together the ported boxes tonight. I’ll let them sit in the clamps overnight. The box turned out really nice. -Trevor

              Comment


              • #82
                lol, well there is always this...

                Click image for larger version

Name:	Screenshot 2020-09-13 220931.jpg
Views:	100
Size:	49.3 KB
ID:	1451174 Click image for larger version

Name:	Screenshot 2020-09-13 221023.jpg
Views:	96
Size:	301.2 KB
ID:	1451175

                Comment


                • #83
                  Do not use this last network. That 44 ohm resistor and 0.26mH coil will be across the amplifier outputs and the resistor will get HOT. The phase was better in the first one after I mentioned the phase alignment than the 2 following.

                  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


                  • #84
                    Originally posted by Wolf View Post
                    Do not use this last network. That 44 ohm resistor and 0.26mH coil will be across the amplifier outputs and the resistor will get HOT. The phase was better in the first one after I mentioned the phase alignment than the 2 following.

                    Later,
                    Wolf
                    Thanks Wolf! That last network was posted mostly as a joke.

                    Comment


                    • #85
                      I don't know why it's a joke, as I've done similar before. More parts are not always a bad thing.
                      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


                      • #86
                        Originally posted by Wolf View Post
                        I don't know why it's a joke, as I've done similar before. More parts are not always a bad thing. Wolf
                        The notch filter I put on the tweeter is centered around 13kHz mostly as the joke. Granted, half of me thought maybe I had stumbled onto something that might work. As you know, I have zero experience building passive crossovers so when, for example, someone like you looks at a crossover network and can tell from the schematic that something will get hot I have zero clue why that is. It is super intimidating posting this stuff when there is 100% chance of looking foolish. I’m having fun learning though and I do appreciate your experience and input. -Trevor

                        Comment


                        • a4eaudio
                          a4eaudio commented
                          Editing a comment
                          I don't think you look foolish at all. You look like someone trying to design their first crossover who acknowledges they need help.

                      • #87
                        Originally posted by trevordj View Post
                        The notch filter I put on the tweeter is centered around 13kHz mostly as the joke. Granted, half of me thought maybe I had stumbled onto something that might work. As you know, I have zero experience building passive crossovers so when, for example, someone like you looks at a crossover network and can tell from the schematic that something will get hot I have zero clue why that is. It is super intimidating posting this stuff when there is 100% chance of looking foolish. I’m having fun learning though and I do appreciate your experience and input. -Trevor
                        That's why you should post these x-overs. You will learn more! No one will think less of you. In fact, a large percentage here can't do their own xo.

                        There's a handful of tricks that come in handy, but they may not be used by many. There's a hundred ways to do a speaker xo. The trick is finding the best compromise. There is no best x-over really. Some are clever. Some are complicated. Some use a minimal number of parts, but would be better with more parts. Sometimes it's a budget compromise. sometimes it's a small box, and room is scarce. I hate small speakers. There's no room for a 12 part xo!. Well, there is, but it's harder.

                        Comment


                        • #88
                          Ok guys, some more updates for today. I cleaned up the boxes after glue up and got the drivers and ports mounted.



                          I also wanted to try a different iteration of the XT25 tweeter in the horn. I forgot I have two XT25SC90s in storage. I read something about removing the flange so I went for it. The first one, I ruined. The second one was a success though.



                          I drew up a 3D model of a mounting bracket in Fusion 360 and cut it out.

                          Click image for larger version

Name:	Joudas Flangeless XT25 Horn Adapter v1.jpg
Views:	72
Size:	44.5 KB
ID:	1451354


                          Using this will allow more flush mounting in the horn throat. I’m hoping that will help with some of the measurements. I read a thread on here where this exact tweeter was used in this waveguide with good results. -Trevor

                          Comment


                          • #89
                            I took some measurements in the ported box with the different tweeter.

                            Click image for larger version  Name:	Screenshot 2020-09-14 210823.jpg Views:	0 Size:	113.1 KB ID:	1451357 Click image for larger version  Name:	Screenshot 2020-09-14 210903.jpg Views:	0 Size:	104.2 KB ID:	1451358

                            Woofer looks as expected, ugly above 1500hz. Measurements are at 0, 30, and 60 degrees


                            Click image for larger version  Name:	NE180W-08_ported_FR.jpg Views:	0 Size:	165.4 KB ID:	1451359


                            Tweeter looks better in my opinion, the ringing/cone breakup/horn honk above 10k is gone.


                            Click image for larger version  Name:	XT25SC90-04_FR.jpg Views:	0 Size:	161.6 KB ID:	1451360

                            Comment


                            • #90
                              I came up with a couple crossover sims, I am interested in your feedback. The first is complicated but has good phase alignment and manageable impedance across the board.

                              Click image for larger version  Name:	Screenshot 2020-09-14 205115.jpg Views:	0 Size:	77.7 KB ID:	1451362 Click image for larger version  Name:	Screenshot 2020-09-14 205245.jpg Views:	0 Size:	311.5 KB ID:	1451363

                              The other crossover has more even directivity but lower impedance and less optimal phase alignment on axis. At 30 and 60 degrees phase alignment looks good though.

                              Click image for larger version  Name:	Screenshot 2020-09-14 205157.jpg Views:	0 Size:	43.9 KB ID:	1451364

                              Click image for larger version  Name:	Screenshot 2020-09-14 205315.jpg Views:	0 Size:	313.8 KB ID:	1451365

                              Comment

                              Working...
                              X