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The Chorales - An Usher / Vifa Project

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  • #61
    Re: The Chorales - An Usher / Vifa Project

    Well, I'm going to build the crossover as is, and listen to the speakers first, then have Shawn, Beau, Jon, Matt and Johnny listen them and judge the sound quality - after 3 beers. I'll make changes as needed. Thanks everyone.
    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


    • #62
      Re: The Chorales - An Usher / Vifa Project

      Originally posted by hongrn View Post
      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.
      I shoot for +/-2dB or less if possible. Minimum is +/-3dB.
      However- that is for on axis response. Since this is likely a breakup in the woofer causing that bump, you may be able to hear it bark in music or make a bit of a resonance. I've seen it stated and restated it myself that energy storage and breakup/resonances should be suppressed to a minimum of -40dB before they become typically inaudible or unintelligible, and that -50dB from reference is a wash.

      I know I've heard it in some drivers even after I had the response flat. The suppression was just not significant. This is one of the many colorations that make speakers sound different, aside from just being different drivers.

      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


      • #63
        Re: The Chorales - An Usher / Vifa Project

        Originally posted by hongrn View Post
        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.
        It's a tough call without listening. Looks like about $32 additional cost. If this was going to be your last speakers for a long while, and if you also tend to be a critical listener, then I'd spend the extra money, assuming you could still fit everything in the box. On the other hand, if you think that you might later replace the tweeter with something that can cross lower, then a notch likely would not be needed. Just for practice though, I think you should add a notch to the sim, and see what you can do to improve things.

        Comment


        • #64
          Re: The Chorales - An Usher / Vifa Project

          Originally posted by hongrn View Post
          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.
          Many speakers that people love have a dip there, you might try taking 2 even 3 dB off there and make it broad.
          you could move the tweeter XO up a bit also. If you had a +/- 1 or 2 dB tolerance, put that range at the bottom of
          the span. I suggest experimenting, maybe build it flat then use EQ or whatever you are most comfortable with.
          Or build it as designed as you said, then switch in and out the trap that people are suggesting so that you can
          hear the difference, try different depths and widths.

          I take it you've heard of the BBC dip?

          While you're at it, you might try taking 1-2 dB off of the tweeter output to also put it at the bottom of your tolerance,
          since many feel that this is a more natural tonal balance and so many recordings are made HOT these days. There
          is no absolutely right answer you just want it to sound balanced on as much good listening material.
          Remember also that we adapt to some response errors, so listen to a new curve for 5 or 10 well balanced cuts and
          give it overnight for the brain to "recalibrate".
          Article in .ppt power point format on adaptation by David Griesinger who was a guru at Lexicon:
          http://www.davidgriesinger.com/
          http://www.davidgriesinger.com/binaural_hearing.ppt

          I suggest that you experiment since this is the voicing process and it can take a design from good to excellent.

          I like your design by the way and am working on an Usher design myself at the moment - not the same drivers.
          Last edited by Pete Basel; 06-26-2015, 07:39 PM.

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          • #65
            Re: The Chorales - An Usher / Vifa Project

            Since you're planning on a listening session, have a comparison with and without the notch and post the findings. I think many would be interested in the outcome.
            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.

            Comment


            • #66
              Re: The Chorales - An Usher / Vifa Project

              Originally posted by kenny_k View Post
              Since you're planning on a listening session, have a comparison with and without the notch and post the findings. I think many would be interested in the outcome.
              +1

              Comment


              • #67
                Re: The Chorales - An Usher / Vifa Project

                ++1
                Paul

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

                Comment


                • #68
                  Re: The Chorales - An Usher / Vifa Project

                  Gents, please take a look at this latest version and let me know if it looks OK to you. I took care of the 3kHz bump, and except for one bump, everything is within +/- 2dB. By the way, this has been one heck of a great lesson on crossover design for me with all the coaches on this forum. The left pic is the previous version, the right pic the most recent one. Just click on "Next" and "Previous" to compare the two versions. And don't hold back your criticisms. Thanks.

                  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


                  • #69
                    Re: The Chorales - An Usher / Vifa Project

                    Originally posted by hongrn View Post
                    Gents, please take a look at this latest version and let me know if it looks OK to you. I took care of the 3kHz bump, and except for one bump, everything is within +/- 2dB. By the way, this has been one heck of a great lesson on crossover design for me with all the coaches on this forum. The left pic is the previous version, the right pic the most recent one. Just click on "Next" and "Previous" to compare the two versions. And don't hold back your criticisms. Thanks.

                    Hong
                    time to start listening and voicing them.
                    craigk

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

                    Comment


                    • #70
                      Re: The Chorales - An Usher / Vifa Project

                      Originally posted by hongrn View Post
                      Gents, please take a look at this latest version and let me know if it looks OK to you. I took care of the 3kHz bump, and except for one bump, everything is within +/- 2dB. By the way, this has been one heck of a great lesson on crossover design for me with all the coaches on this forum. The left pic is the previous version, the right pic the most recent one. Just click on "Next" and "Previous" to compare the two versions. And don't hold back your criticisms. Thanks.

                      Hong
                      Lets make an assumption that may, or may not be true. Lets assume that if you measured the woofer, and made a waterfall plot, and there is a long ridge at 2.8k that rings for what seems an eternity. With your speakers current x-over that ringing will still be present. It just starts at a point 8 dB lower in level. Now lets add a notch, and reduce it to 12 dB below the level of the tweeter. It will still ring, but now it's starting at 12 dB below the tweeter level, and should be a bit less noticeable, especially since other frequencies will be masking it most of the time. Maybe with some types of music, there's not much to mask it, and maybe the music has a lot of energy there, (like a solo violin) and maybe it bothers you just a little because you want it as close to perfect as possible, so you notch it another 30 dB. Now it's probably below the noise floor of the room, and you couldn't hear it even if you tried.

                      If the woofer is not ringing much at all at 2.8k, then its probably of no real advantage to notch it excessively, or at all.

                      Knowing what a problem sounds like, and how to fix it is both handy, and a curse. I improved my current speaker x-over by eliminating similar response issues, but now it's too big to put in the .25 cu-ft box.

                      Comment


                      • #71
                        Re: The Chorales - An Usher / Vifa Project

                        I get your point. Should I be concerned however over such ringing in a paper cone versus a metal cone? By the way, here's the CSD plot from zaphaudio. Thanks.



                        Originally posted by rpb View Post
                        Lets make an assumption that may, or may not be true. Lets assume that if you measured the woofer, and made a waterfall plot, and there is a long ridge at 2.8k that rings for what seems an eternity. With your speakers current x-over that ringing will still be present. It just starts at a point 8 dB lower in level. Now lets add a notch, and reduce it to 12 dB below the level of the tweeter. It will still ring, but now it's starting at 12 dB below the tweeter level, and should be a bit less noticeable, especially since other frequencies will be masking it most of the time. Maybe with some types of music, there's not much to mask it, and maybe the music has a lot of energy there, (like a solo violin) and maybe it bothers you just a little because you want it as close to perfect as possible, so you notch it another 30 dB. Now it's probably below the noise floor of the room, and you couldn't hear it even if you tried.

                        If the woofer is not ringing much at all at 2.8k, then its probably of no real advantage to notch it excessively, or at all.

                        Knowing what a problem sounds like, and how to fix it is both handy, and a curse. I improved my current speaker x-over by eliminating similar response issues, but now it's too big to put in the .25 cu-ft box.
                        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


                        • #72
                          Re: The Chorales - An Usher / Vifa Project

                          Originally posted by hongrn View Post
                          I get your point. Should I be concerned however over such ringing in a paper cone versus a metal cone? By the way, here's the CSD plot from zaphaudio. Thanks.
                          In that CSD I see a damped cone resonance just under 5k. I'd wouldn't sweat it. YMMV.
                          Audio: Media PC -> Sabre ESS 9023 DAC -> Behringer EP2500 -> (insert speakers of the moment)
                          Sites: Jupiter Audioworks - Flicker Stream - FRD Consortium Archive - Proud Member of Midwest Audio Club

                          Comment


                          • #73
                            Re: The Chorales - An Usher / Vifa Project

                            I decided to follow Pete's suggestion and moved the crossover point away from the bump to see if I can get better results. This is at 2kHz with LR4 target slopes, 2nd order electrical with a RLC notch filter on the woofer, and a 3rd order with a RL contour filter on the tweeter. I'm working on the phase, but it looks promising so far.
                            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


                            • #74
                              Re: The Chorales - An Usher / Vifa Project

                              Originally posted by hongrn View Post
                              ....In the mean time, I went to Zaph Audio to look at the measurements of the Ushers and the Vifas to find the best crossover point.
                              Can you provide any insight on methodology to select the crossover frequency based on the driver responses and distortion profiles?

                              Thanks,

                              Rob

                              Comment


                              • #75
                                Re: The Chorales - An Usher / Vifa Project

                                Originally posted by hongrn View Post
                                I get your point. Should I be concerned however over such ringing in a paper cone versus a metal cone? By the way, here's the CSD plot from zaphaudio. Thanks.
                                We may be over thinking this CSD stuff. I used it as an example of why notching might be beneficial. On Zaphs site under "tidbits", he comments on CSD measurements. I don't totally follow his point, but maybe you will.

                                Comment

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