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The Chorales - An Usher / Vifa Project

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  • #46
    Re: The Chorales - An Usher / Vifa Project

    Great project. Looking forward to the rest.
    Subscribed

    Ted

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    • #47
      Re: The Chorales - An Usher / Vifa Project

      Originally posted by hongrn View Post
      Thanks for the suggestion rpb. Here's the latest sim. I like the crossover point better, but the phase tracking sucks, so I'll have to work on that. What do you think Craig?
      If you didn't already, I'd add a notch centered at 650 hz, and pull that area down about 6 dB initially, then as you play with the other woofer parts, gradually bring it back up, and adjust the center and width of the notch. You will probably need a smaller coil, so maybe change that in your sim first. If you look at your raw response overlaying your filtered response, try not to alter the response below about 300 hz. You should be able to eliminate the dip at 450 hz.

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      • #48
        Re: The Chorales - An Usher / Vifa Project

        Here's the latest iteration of the crossover. Please take a look and give me your comments. I think the FR is fairly flat, the phase tracking is quite decent, and the overall impedance stays above 6 ohms. The crossover point is now around 2,300Hz, my original goal. Grueling process for sure, but I'm happy with the results. What do you think? Thanks in advance for helping.

        Hong
        Attached Files
        Some people are addicted to Vicodin. I'm addicted to speaker building.

        The Chorales - Usher 8945A/Vifa XT25TG Build
        ESP Project 101 Lateral MOSFET Amplifier
        LM4780 Parallel Chipamp
        Sonata Soundbar Project
        The Renditions - Active/Passive Towers

        Comment


        • #49
          Re: The Chorales - An Usher / Vifa Project

          Nice deep reverse null, Hong, and the 2.3k crossover puts the XT25 well within its comfort zone. Looks good to me :-)

          Comment


          • #50
            Re: The Chorales - An Usher / Vifa Project

            Originally posted by hongrn View Post
            Here's the latest iteration of the crossover. Please take a look and give me your comments. I think the FR is fairly flat, the phase tracking is quite decent, and the overall impedance stays above 6 ohms. The crossover point is now around 2,300Hz, my original goal. Grueling process for sure, but I'm happy with the results. What do you think? Thanks in advance for helping.

            Hong
            Looks really good.
            craigk

            " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

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            • #51
              Re: The Chorales - An Usher / Vifa Project

              Can't wait to hear it Hong!

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              • #52
                Re: The Chorales - An Usher / Vifa Project

                Originally posted by hongrn View Post
                Here's the latest iteration of the crossover. Please take a look and give me your comments. I think the FR is fairly flat, the phase tracking is quite decent, and the overall impedance stays above 6 ohms. The crossover point is now around 2,300Hz, my original goal. Grueling process for sure, but I'm happy with the results. What do you think? Thanks in advance for helping.

                Hong
                Looks really good. I'd maybe add a notch at 20k to bring the very top end down slightly. I know at some point you have to draw the line on x-over parts, but in a perfect world where there's lots of room in the box, and someone else is paying for the parts, I'd add a narrow notch on the woofer at 3k, and bring it down about 4 dB. (Expensive! 4 mH .7uf and 10 ohms should do it.)
                Last edited by rpb; 06-25-2015, 07:53 PM.

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                • #53
                  Re: The Chorales - An Usher / Vifa Project

                  Thanks everyone for your help. This forum is awesome. I couldn't have pulled this off without your coaching and advice. Time to build this crossover. I'll post the measurements, listening impressions, and the schematics soon. Thanks again.

                  Hong
                  Some people are addicted to Vicodin. I'm addicted to speaker building.

                  The Chorales - Usher 8945A/Vifa XT25TG Build
                  ESP Project 101 Lateral MOSFET Amplifier
                  LM4780 Parallel Chipamp
                  Sonata Soundbar Project
                  The Renditions - Active/Passive Towers

                  Comment


                  • #54
                    Re: The Chorales - An Usher / Vifa Project

                    Damn. that looks great. Build it and bring them to Grinnell Iowa Oct 24th......................Or else!
                    " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

                    Quote Originally Posted by hongrn. Oct 2014
                    Do you realize that being an American is like winning the biggest jackpot ever??

                    http://www.midwestaudioclub.com/spot...owell-simpson/
                    http://s413.photobucket.com/albums/pp216/arlis/

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                    • #55
                      Re: The Chorales - An Usher / Vifa Project

                      I wonder if a Satori 6.5" would work...........................:rolleyes:
                      Kenny

                      http://www.diy-ny.com/
                      DIY NY/NJ 2014 https://www.youtube.com/watch?v=FGwA...ature=youtu.be
                      Man does not live by measurements alone, a little music helps.

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                      • #56
                        Re: The Chorales - An Usher / Vifa Project

                        Originally posted by hongrn View Post
                        Here's the latest iteration of the crossover. Please take a look and give me your comments. I think the FR is fairly flat, the phase tracking is quite decent, and the overall impedance stays above 6 ohms. The crossover point is now around 2,300Hz, my original goal. Grueling process for sure, but I'm happy with the results. What do you think? Thanks in advance for helping.

                        Hong
                        I know I'm picking nits, but the bump in the woofer at 2.8k might be audible, and it's what is causing the peak in the FR. A small notch may improve things for you.
                        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:
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                        http://techtalk.parts-express.com/blog.php?u=4102

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                        • #57
                          Re: The Chorales - An Usher / Vifa Project

                          Originally posted by Wolf View Post
                          I know I'm picking nits, but the bump in the woofer at 2.8k might be audible, and it's what is causing the peak in the FR. A small notch may improve things for you.
                          Later,
                          Wolf
                          I agree, and suggested some values for the notch in post #52. After adding this notch, some of the other parts will probably need some additional tweaking to optimize the response.

                          Comment


                          • #58
                            Re: The Chorales - An Usher / Vifa Project

                            Originally posted by Wolf View Post
                            I know I'm picking nits, but the bump in the woofer at 2.8k might be audible, and it's what is causing the peak in the FR. A small notch may improve things for you.
                            Later,
                            Wolf
                            Originally posted by rpb View Post
                            I agree, and suggested some values for the notch in post #52. After adding this notch, some of the other parts will probably need some additional tweaking to optimize the response.
                            I hear you both, but let me ask you a couple of questions that I need answers to:

                            1) Is there a need to hammer down every single little bump in the frequency response, when the room in which the speakers will be placed will play havoc with the FR anyway?

                            2) Is there a tolerance that is acceptable (+/- 2, 3dB), since not all FR plots will be ruler flat? As an example, here's the FR plot from one of B&W's offerings, the 684 S2. Thanks.
                            Attached Files
                            Some people are addicted to Vicodin. I'm addicted to speaker building.

                            The Chorales - Usher 8945A/Vifa XT25TG Build
                            ESP Project 101 Lateral MOSFET Amplifier
                            LM4780 Parallel Chipamp
                            Sonata Soundbar Project
                            The Renditions - Active/Passive Towers

                            Comment


                            • #59
                              Re: The Chorales - An Usher / Vifa Project

                              Consider the range where the ear is most sensitive around 1-5 KHz, other bumps
                              only matter if they are audible. A small one above 15K probably not, one in the
                              mid bass will depend a lot on placement. In fact a rising high end _improves_ the
                              power response. Reviews tend to spatially average the on axis response a bit and
                              that usually tilts down the high end.
                              Why don't you try moving the woofer xo down 10 - 20 % in order to reduce the bump?
                              Adjust the Q by altering the ratio of the LP filter values.
                              Easy enough to do in simulation.

                              Comment


                              • #60
                                Re: The Chorales - An Usher / Vifa Project

                                Pete,

                                The bump may be about a decibel or less higher than the overall FR plot. Are our ears that sensitive, even in the region that you mentioned? I'll try your suggestion this weekend. Thanks.

                                Originally posted by Pete Basel View Post
                                Consider the range where the ear is most sensitive around 1-5 KHz, other bumps
                                only matter if they are audible. A small one above 15K probably not, one in the
                                mid bass will depend a lot on placement. In fact a rising high end _improves_ the
                                power response. Reviews tend to spatially average the on axis response a bit and
                                that usually tilts down the high end.
                                Why don't you try moving the woofer xo down 10 - 20 % in order to reduce the bump?
                                Adjust the Q by altering the ratio of the LP filter values.
                                Easy enough to do in simulation.
                                Some people are addicted to Vicodin. I'm addicted to speaker building.

                                The Chorales - Usher 8945A/Vifa XT25TG Build
                                ESP Project 101 Lateral MOSFET Amplifier
                                LM4780 Parallel Chipamp
                                Sonata Soundbar Project
                                The Renditions - Active/Passive Towers

                                Comment

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