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Vifa NE19VCT04 Measurements in Waveguides

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  • Vifa NE19VCT04 Measurements in Waveguides

    Brandon, AugerPro, sent me the NE19 and the NE25 to test in some of my waveguides.
    At first I wasn't having much luck at all but I was trying to fit my guides over the faceplate that has the two protective bars over it. thought about removing the bars but didn't want to damage the tweeter. Once I figured out that I could take an exacto knife around the faceplate to remove the adhesive, then twist the faceplate about a 1/4" it would lifted right off so I was in business.

    This is the flat baffle measurements 0 20 30 40 50 60 degrees.


    This is a 7.5" dia. x 2" deep with a 3.95" rad. x .75" throat. 0 20 30 40 50 60 degrees.


    This is flat baffel red vs guide blue 0 axis


    This is flat baffle red vs guide blue 20 degrees


    This is flat baffle red vs guide blue 30 degrees


    This is flat baffle red vs guide blue 40 degrees


    This is flat baffle red vs guide blue 50 degrees


    This is flat baffle red vs guide blue 60 degrees. I probably could get more boost at 60 degrees in the 4kHz -20kHz range but I believe it would be in trade off for upper on axis response causing a a lose of a few dbs. I feel if I can keep the flat baffle off axis of 50 to 60 degrees matching the guide off axis 50 60 degrees that's a good starting point.


    I'll run some of my eliptical and smaller guides next to see what I can get.
    Very happy with this tweeter and guide set up.

    Dave
    http://www.pellegreneacoustics.com/

    Trench Seam Method for MDF
    https://picasaweb.google.com/101632266659473725850

  • #2
    Re: Vifa NE19VCT04 Measurements in Waveguides

    Wow. Really looking forward to the small waveguide also. Feel free to cut the bars off, unless you think you really need that extra depth gained by having the faceplate off. Be interesting to see the difference. So what holds the diaphragm down?
    ~Brandon

    Soma Sonus
    DriverVault

    Comment


    • #3
      Re: Vifa NE19VCT04 Measurements in Waveguides

      Originally posted by augerpro View Post
      Wow. Really looking forward to the small waveguide also. Feel free to cut the bars off, unless you think you really need that extra depth gained by having the faceplate off. Be interesting to see the difference. So what holds the diaphragm down?

      The diaphram is glued down. It basically looks the same as the OT19 or the OX20 without the faceplate. The NE19 will fit right into the base plate I made for the OT19.

      This is a graph of the NE19 with the same 7.5 guide with the faceplate attached and the throat of the guide fits just outside the bevel on the face plate. As you can see the dip in the on axis.


      This is using the base plate I made for the OT19 with the same guide as the new base plate I made for the NE19. Not bad at all. It would be interesting to try the OT19 in my new base plate.


      I've already tested the NE19 in an eliptical guide 4.5" x 6.26" and a 4" guide using the base plate of the OT19 but I want to run them through the new base plate before posting the results.

      Dave
      http://www.pellegreneacoustics.com/

      Trench Seam Method for MDF
      https://picasaweb.google.com/101632266659473725850

      Comment


      • #4
        Re: Vifa NE19VCT04 Measurements in Waveguides

        Gotta hand it to DanP for stumbling onto that excellent profile.

        Nice work again Dave.
        R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
        Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

        95% of Climate Models Agree: The Observations Must be Wrong
        "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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        • #5
          Re: Vifa NE19VCT04 Measurements in Waveguides

          Gotta hand it to DanP for stumbling onto that excellent profile.

          Nice work again Dave.
          Yeah this is very promising. I'll probably buy some of the ellipticals now that Dave is using some tweeters I'm interested in using. The old Peerless 810921 is another I'd like to see. I can send one of those too if Dave is interested. Those will probably require the faceplate be removed also.
          ~Brandon

          Soma Sonus
          DriverVault

          Comment


          • #6
            Re: Vifa NE19VCT04 Measurements in Waveguides

            damn dave, this isn't even hard for you anymore. nice, really.
            " 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/

            Comment


            • #7
              Re: Vifa NE19VCT04 Measurements in Waveguides

              Gotta hand it to DanP for stumbling onto that excellent profile.

              Nice work again Dave.
              Thanks! Thought you might recognize that radius. I didn't know Dan came up with that. Thanks Dan.

              Dave
              http://www.pellegreneacoustics.com/

              Trench Seam Method for MDF
              https://picasaweb.google.com/101632266659473725850

              Comment


              • #8
                Re: Vifa NE19VCT04 Measurements in Waveguides

                Originally posted by [email protected] View Post
                damn dave, this isn't even hard for you anymore. nice, really.
                I am starting to figure out how to manipulate the base plates to adjust for dips in the response. I'm even starting to cut down on the time it takes to figure it out but it is still very time consuming. Every time I work with a new tweeter I learn new methods and I am starting to figure out similarities so hopefully this will end up were I can make up a bunch of guides and base plates at a time and interchange them. If so I can offer the guides at a more reasonable cost. Hopefully I can get to a point that I can make enough money to make it worth my time and also make it affordable for someone not to spend more on the guide then the tweeter. It's like anything else if you put the time into it you get better and faster at it.
                Now if I could just get back to building speakers!
                Thanks
                Dave
                http://www.pellegreneacoustics.com/

                Trench Seam Method for MDF
                https://picasaweb.google.com/101632266659473725850

                Comment


                • #9
                  Re: Vifa NE19VCT04 Measurements in Waveguides

                  *sigh* I am the only one who likes the on baffle result better, huh? Why would anyone need that much extra power from 1-4K? Just does not make scene to me in a home environment IMHO. From what I can see of this one, I would not cross any lower either because of the WG. I would just end up with a shaping circuit to make up for the loss it power which appears to start around 6K, heck at 60deg your already -20dB by 4K off axis. Which makes sense since the 3.95" radius. The only advantage I see is it does smooth out abberations off axis, which at the frequencies they occur may be moot since there would be several reflections IN ROOM before it even gets to the listener. Even then they occur within a 5dB (+/-2.5dB) window.

                  It is great work though on WG development, and certinly much smoother than a lot of what you normally see with WGs Skeptically following with an open mind!
                  .

                  Comment


                  • #10
                    Re: Vifa NE19VCT04 Measurements in Waveguides

                    Originally posted by mzisserson View Post
                    *sigh* I am the only one who likes the on baffle result better, huh? Why would anyone need that much extra power from 1-4K? Just does not make scene to me in a home environment IMHO. From what I can see of this one, I would not cross any lower either because of the WG. I would just end up with a shaping circuit to make up for the loss it power which appears to start around 6K, heck at 60deg your already -20dB by 4K off axis. Which makes sense since the 3.95" radius. The only advantage I see is it does smooth out abberations off axis, which at the frequencies they occur may be moot since there would be several reflections IN ROOM before it even gets to the listener. Even then they occur within a 5dB (+/-2.5dB) window.

                    It is great work though on WG development, and certinly much smoother than a lot of what you normally see with WGs Skeptically following with an open mind!
                    That's the great thing about all this. You can pick your poison.

                    Dave
                    http://www.pellegreneacoustics.com/

                    Trench Seam Method for MDF
                    https://picasaweb.google.com/101632266659473725850

                    Comment


                    • #11
                      Re: Vifa NE19VCT04 Measurements in Waveguides

                      Originally posted by mzisserson View Post
                      *sigh* I am the only one who likes the on baffle result better, huh? Why would anyone need that much extra power from 1-4K? Just does not make scene to me in a home environment IMHO. From what I can see of this one, I would not cross any lower either because of the WG. I would just end up with a shaping circuit to make up for the loss it power which appears to start around 6K, heck at 60deg your already -20dB by 4K off axis. Which makes sense since the 3.95" radius. The only advantage I see is it does smooth out abberations off axis, which at the frequencies they occur may be moot since there would be several reflections IN ROOM before it even gets to the listener. Even then they occur within a 5dB (+/-2.5dB) window.

                      It is great work though on WG development, and certinly much smoother than a lot of what you normally see with WGs Skeptically following with an open mind!
                      Mike were are you -20dbs at 4kHz at 60 degrees off axis. It's dead on at that point. Red is flat baffle Blue is Guide.


                      Dave
                      http://www.pellegreneacoustics.com/

                      Trench Seam Method for MDF
                      https://picasaweb.google.com/101632266659473725850

                      Comment


                      • #12
                        Re: Vifa NE19VCT04 Measurements in Waveguides

                        More results on smaller guides.

                        This is an elliptical guide measures 6.5 x 4.75 by 1.86 deep with a 1" throat with a base plate that further reduces to .75". It appears to give more boost off axis in the upper octaves but also gives up the boost in the lower octaves compared to the 7.5" dia. guide.



                        This is the 4" dia. x 1" deep guide from DanN. "Chameleon" speaker. Only difference is the NE19 liked the .75" throat on the guide instead of the 1" throat that it seemed to like better on all the other guides.



                        Dave
                        http://www.pellegreneacoustics.com/

                        Trench Seam Method for MDF
                        https://picasaweb.google.com/101632266659473725850

                        Comment


                        • #13
                          Re: Vifa NE19VCT04 Measurements in Waveguides

                          Unless I am reading it wrong, the first two graphs you posted... The WG falls off quick off axis when compared to on axis. In the WG there is a 10dB spread by the time you get to 4K on axis and 60deg, when compared to it's peak loading you are 20dB down. I just wonder about the audible effects of it, and I would imagine this is why WG's/Horns have such a tight sweet spot. Also if you are losing that much response that quickly at such a low Fq, you are missing spatial ques that contribute to imaging, and the sonic ques that define precieved resolution such as the "click" of a guitar pick on a string when listing to a well recorded piece of music.

                          It is pick your poison world, I was not trying to say "right" or "wrong", but there are different ways of reading these things and I never see any other measurements than FR with waveguides. Tough to gather an accurate picture with only one small part of the puzzle. I just do not want anyone to be mislead that based upon one measurement this is the best option for them because at first glance it looks good. Everyone should have all the information to make their own decision. It is great work like I said around WG's though and closer to where they need to be. There is no doubting the eff gain though the lower pass-band and flat-out control with little to no diffraction signature.

                          I am just trying to put it all together because I am still trying to find a WG speaker I would own and with all the hubbub around WG's over the past year or so I am frustrated I do not have a better understanding of why the rage. Maybe at the end of the day, it is a to each their own thing and that is fine too. I never have been one to always go with the grain, but there has to be something good here because of the work being done by the great designers doing it, I feel I am the one missing the boat here, not the other way around. Make sense?
                          .

                          Comment


                          • #14
                            Re: Vifa NE19VCT04 Measurements in Waveguides

                            Mike,

                            It's the uniformity of the response as you move off axis is where a waveguide shows its chops. Once you EQ the on-axis to flat, the response shows the same smooth response as you move off axis, even though the entire range is dropping.

                            The flat baffle response shows an "omni" pattern to roughly 5KHz. Pair that up with a 6" midwoofer with diminishing off axis response above 2KHz, and you get a "bloom" in response off axis for the system. In a lively environment, that extra energy in the 4KHz region might present a bit of fatigue. If the room is somewhat dead, then it doesn't matter as much one way or the other.



                            This larger guide is begging to be used with a large format woofer, 8" at least, maybe even 12", whose directivity is narrowing around 1KHz.

                            R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
                            Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

                            95% of Climate Models Agree: The Observations Must be Wrong
                            "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

                            Comment


                            • #15
                              Re: Vifa NE19VCT04 Measurements in Waveguides

                              That's what large guides are for, crossing low!

                              Would make sense why a WG would show well in a large, open space like a hotel meeting room, but that is why they exist anyway. What about 90% of living rooms that are pretty neutral, not overly dead, but not exactly reflective with lots of diffusion?
                              .

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