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Transducer Labs N26C Ceramic tweeter in waveguide measurements

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  • Transducer Labs N26C Ceramic tweeter in waveguide measurements

    Hi all.

    I was finally able to get some preliminary measurements of this tweeter on a flat baffle (sort of infinite baffle) and with some custom waveguides. The Transducer labs tweeter is a ceramic dome tweeter. You can read about it here:
    TDL N26C



    First let me tell you how these were measured. I used Jeff Bagby's method of laying them on the floor and measuring with the mic directly above. In this case, the tweeter sits down in some wood that has a cutout in it. A piece of cardboard was placed over the wood to act as a baffle. A cutout was made in the cardboard to simulate a flush mount. The mic was set above the tweeter and at a distance of 27.25" or 69cm from the front plate of the tweeter. The gated window was 2.7ms to block out the main first reflections. The waveguides were simply set on top of the tweeter, held by their weight alone. Then some insulation was placed around the edges of the waveguides. Below are some photos so you can better envision the setup, which is sort of cobbled together.


    I got my N26C's from Meniscus and they include a small metal mesh grill that can be attached over the ceramic dome to protect it. Below shows the flat baffle measurements with and without the mesh grill in place. The mesh grill appears to boost the response slightly on the upper end. All waveguide measurements were taken without the mesh grill as the waveguide throats are too small for them to fit.

    The waveguides measured were prototypes created by DanP here at Tech talk. Dan created 3 custom waveguides that are a range of sizes and depths. The smallest one is 140mm dia.x33mm deep. The other two increased in size to 152mm and 165mm dia. with depths of 36mm and 39mm respectively. All the throat openings are 36mm. The face plate opening on the N26C is 34.5mm, according to the guys at Transducer Labs. I also tested the N26C in the MCM waveguide, which I understand is NLA.


    These waveguides are made using an additive manufacturing process that sinters (lightly melts with a laser) successive 0.15mm layers of nylon/glass powder. Therefore, the possible geometries are not limited by traditional CNC or molding restrictions. I have some rectangular ones on the way to test with the B&G neo3.


    I guess they can be painted, as long as they are sealed first; otherwise they soak up the paint. They actually look pretty cool as they are, can be sanded and will hold screws like a dense wood, according to Dan. Of course, they are generally intended to be used as patterns to have waveguides either turned, created with a cnc or with a tool like the radarcarve. The latter is how the ones that Pete S. used in his Aurora 2ways were done, which were also patterned from waveguides that DanP fashioned for him to test.

    In the next post I will show the waveguide results.
    Dan N.

  • #2
    Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

    Interestingly, there was very little difference on the bottom end of the waveguides. They were all essentially the same. They differ primarily in the upper end, on axis smoothness.





    I'm very pleased with the performance at this point, especially considering the diminutive size of the 140mm.

    140mm


    152mm


    165mm


    140mm+152mm+165mm+mcm



    Dan N.

    Comment


    • #3
      Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

      Thanks for the great post.
      :blues: Flat frequency response, a smooth sound power response free of resonance, careful driver-integration, and high dynamic range both upward and downward :blues:

      Comment


      • #4
        Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

        So how does it sound?

        Comment


        • #5
          Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

          Originally posted by dlneubec View Post
          ... I also tested the N26C in the MCM waveguide, which I understand is NLA...
          The MCM waveguide can be sourced as part number: PH65 from Pyle.

          Here's a source. Note: I am not familiar with the vendor:
          http://www.emazingaudio.com/vmchk/-d...uct-flyer.html

          Comment


          • #6
            Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

            Great work Dan! Have you tried some flattening components yet to see how this arrangement does to 2khz? We can see by your graphs that it holds pattern control to 1.5khz or so there's lots of possibilities with this tweeter if it can cross that low. A high powered dual 8" MTM is within the realm of possibilities.

            Comment


            • #7
              Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

              Awesome Dan, nice to see you working with these tweeters. I'm looking forward to hearing your project in action later this year. It looks like the 140mm guide provides a response that will require a much simpler crossover circuit since that notch at 6kHz hasn't developed yet with it. It would be real easy to flatten that response and extend it to nice low crossover point.
              Click here for Jeff Bagby's Loudspeaker Design Software

              Comment


              • #8
                Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

                Originally posted by Cazten View Post
                So how does it sound?
                Unfortunately, I'm not even close to listening to it. I'm still in the project planning and design stage. I've not even started on the actual build yet.:(
                Dan N.

                Comment


                • #9
                  Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

                  Originally posted by Mayhem13 View Post
                  Great work Dan! Have you tried some flattening components yet to see how this arrangement does to 2khz? We can see by your graphs that it holds pattern control to 1.5khz or so there's lots of possibilities with this tweeter if it can cross that low. A high powered dual 8" MTM is within the realm of possibilities.
                  I have not had a chance to do any modeling with it, but will be investigating how low it can go. It does look like it could get down to 1.5-2khz pretty comfortably. I was rather surprised that much boost and pattern control in a WG that is only 5.5"dia. about 1.3" deep.

                  I'm planning it for a 3way, however.
                  Dan N.

                  Comment


                  • #10
                    Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

                    Originally posted by Jeff B. View Post
                    Awesome Dan, nice to see you working with these tweeters. I'm looking forward to hearing your project in action later this year. It looks like the 140mm guide provides a response that will require a much simpler crossover circuit since that notch at 6kHz hasn't developed yet with it. It would be real easy to flatten that response and extend it to nice low crossover point.
                    Thanks, Jeff, your floor method for doing this kind of measurement worked very well! I'm hoping for a simple XO.
                    Dan N.

                    Comment


                    • #11
                      Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

                      Originally posted by dlneubec View Post
                      I have not had a chance to do any modeling with it, but will be investigating how low it can go. It does look like it could get down to 1.5-2khz pretty comfortably. I was rather surprised that much boost and pattern control in a WG that is only 5.5"dia. about 1.3" deep.

                      I'm planning it for a 3way, however.
                      Based on the distortion measurements I took, I would think the 1.5khz crossover point with the waveguide is easily a possibility.

                      Click here for Jeff Bagby's Loudspeaker Design Software

                      Comment


                      • #12
                        Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

                        Strange the smallest one was best, bonus. I suppose with that tweeter and in a 3way, the waveguide is for directivity more than anything? It's not like you'll need boost. Won't that tweeter cross very low naked?
                        https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

                        Comment


                        • #13
                          Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

                          But the boost from the waveguide allows you to deliver much less voltage at 1.5kHz for flat response compared to being mounted on a flat baffle, and this can significantly increase power handling and lower distortion even further. That's the added advantage.

                          Jeff

                          Originally posted by ryanbouma View Post
                          Strange the smallest one was best, bonus. I suppose with that tweeter and in a 3way, the waveguide is for directivity more than anything? It's not like you'll need boost. Won't that tweeter cross very low naked?
                          Click here for Jeff Bagby's Loudspeaker Design Software

                          Comment


                          • #14
                            Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

                            I'm aware, just not sure it's the boost that'll benefit this application very much. The directivity is likely more important in this application. I'm not sure less distortion than that will be all that audible if crossing above 2khz. Perhaps it's still going to cross below 2khz?

                            Isn't the same voltage applied, just less current will pass? Therefore less wattage? Unless you mean active.

                            Nice combo.
                            https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

                            Comment


                            • #15
                              Re: Transducer Labs N26C Ceramic tweeter in waveguide measurements

                              Originally posted by ryanbouma View Post
                              I'm aware, just not sure it's the boost that'll benefit this application very much. The directivity is likely more important in this application. I'm not sure less distortion than that will be all that audible if crossing above 2khz. Perhaps it's still going to cross below 2khz?

                              Isn't the same voltage applied, just less current will pass? Therefore less wattage? Unless you mean active.

                              Nice combo.
                              I am expecting to see a lower crossover point than that in the end.

                              How do you get less wattage with the same voltage to the driver?

                              No, if you roll the tweeter off 10dB to have flat response at 1.5kHz, that's a significant reduction is drive voltage at that frequency, which translates to less wattage too. ( One tenth as much - a big difference in power handling).
                              Click here for Jeff Bagby's Loudspeaker Design Software

                              Comment

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