Announcement

Collapse
No announcement yet.

Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

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

  • Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

    Dan Neubecker sent me the OT19 to see what I could do with it in a guide. He wanted it to be no more then 4.25" and about .75" to 1" deep. He had a great idea of making the guide fit into the recess of the RS28 and other tweeters with the same diameter. I measured my RS28 and it was just under 4 1/8" so I cut the guide 4 1/16". Figured finish usually takes up the extra space. Anyway I was able to reduce the throat size to just over 3/4" and make a base plate that held the guide just above the surround.

    This is on a 13"x13" flat baffle with a 30 degree bevel on the edges sitting on a box the same size. This seems to be the best method I have found to minimize baffle edge diffraction.

    Flat baffle 0 2 30 40 50 60


    4 1/16" round guide 1" deep with 3/4" throat.
    0 20 30 40 50 60




    Flat baffle in red waveguide in blue
    Flat vs guide on axis


    Flat vs guide 20 degrees


    Flat vs guide 30 degrees


    Flat vs guide 40 degrees


    Flat vs guide 50 degrees


    Flat vs guide 60 degrees


    I sent the guides along with the tweeter back to Dan. Wish I had tried a larger guide to see how the results were but just didn't have time.

    Dave
    http://www.pellegreneacoustics.com/

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

  • #2
    Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

    Round or elliptical? Pics?
    ~Brandon
    Please donate to my Waveguides for CNC and 3D Printing Project!!
    Please donate to my Monster Box Construction Methods Project!!
    Soma Sonus

    Comment


    • #3
      Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

      Looks great, Dave! Good directivity control from 3khz and up, maybe could push an XO to 2.5khz or so and still have a decent directivity match with a small mid in a 3way or midwoofer in a small cone 2way. Boost in the range of 8-10db or so at around 3khz, which should offer a nice increase in headroom and distortion reduction. There is still some boost down to 1khz and nearly up to 20khz, especially off axis. The 1" AC offset benefit is worthy of mention as well. I'm anxious to see how it works in the project I have planned.

      Brandon, this is a 4-1/16" dia. round guide. As Dave mentioned, the idea was for it to be able to fit in the rebate of a 104mm tweeter facepate. 4-1/16" dia potentially offers a workable CTC. An elliptical version provide a similar response but with a narrower vertical footprint.
      Dan N.

      Comment


      • #4
        Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

        You don't get "something for nothing". You trade some 3-5Khz gains and get no gains from 10-20KHz. Hey, I want the whole enchilada. What I want is a silk purse from a sow's ear, which is impossible to do and annoys the heck outta the sow!

        Comment


        • #5
          Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

          Not sure I follow what you are saying. From an SPL standpoint, the 20, 30, 40, and 50 degree responses with the waveguide show gain across the entire spectrum as compared to the flat baffle response.

          What is a potential loss here, primarily, is how close you can place the tweeter to the driver its mated with. It is simply a choice, like any other design decision. They all come at some price, though some provide considerably more value for the price paid.
          Dan N.

          Comment


          • #6
            Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

            Originally posted by Whitneyville1 View Post
            You don't get "something for nothing". You trade some 3-5Khz gains and get no gains from 10-20KHz. Hey, I want the whole enchilada. What I want is a silk purse from a sow's ear, which is impossible to do and annoys the heck outta the sow!
            From what I have seen, and that isn't much, if you get any gain above 12kHz with a guide you are lucky. Most of the time it's a loss. Don't forget this is a very small guide.

            Dave
            http://www.pellegreneacoustics.com/

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

            Comment


            • #7
              Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

              Here are a few pics of the prototype. Dan's finished ones have the base plates painted. However with the clear guide the connection from the guide to the base plate isn't very pretty. I thought I was helping Dan out painting the base plate instead of using clear. As resourceful as Dan is I'm sure he'll figure out what to do with it. Black paint on the face side right around the attachment point would hide it but I would have to have done it free hand. No way that would have turned out good.








              Dave
              Attached Files
              Last edited by davepellegrene; 06-27-2012, 11:07 PM.
              http://www.pellegreneacoustics.com/

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

              Comment


              • #8
                Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

                Very good results from such a small waveguide, well done.

                Comment


                • #9
                  Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

                  Acoustic center alignment with 6dB boost at 2kHz and better controlled directivity - it may not be something for nothing, but it's pretty close. Well done guys. I don't see much reason not to load every tweeter into at least this much WG.

                  Dan
                  _____________________________
                  Tall Boys
                  NRNP Computer Sub
                  The Boxers
                  The Hurricanes
                  The Baronettes
                  Conneccentric
                  UX3

                  Comment


                  • #10
                    Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

                    Those appear to be pictured with the OX20, not the OT19, as that's a ring-radiator.
                    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:
                    https://app.photobucket.com/u/wolf_teeth_speaker

                    My blog/writeups/thoughts here at PE:
                    http://techtalk.parts-express.com/blog.php?u=4102

                    Comment


                    • #11
                      Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

                      Originally posted by Wolf View Post
                      Those appear to be pictured with the OX20, not the OT19, as that's a ring-radiator.
                      Later,
                      Wolf
                      Good observation. I just stuck the OX20 in for the pic. I had already sent the OT19 back to Dan. I do plan to test the OX20 in them though.
                      I do suspect the ring radiator will win out.
                      Dave
                      http://www.pellegreneacoustics.com/

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

                      Comment


                      • #12
                        Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

                        What a coincidence as a couple of days ago, I was going to post a thread asking if anyone has any data with the OT19 in a waveguide, and my desire was for a small 4"ish waveguide at that.
                        These look perfect! Well they be available for sale or just one offs?
                        Also, how do you attach the tweeter to the back if the waveguide?
                        Thanks and great work!
                        Nichikuros - Peerless 831735 Nomex + Vifa NE25VTA
                        Digger8 - Small compact 8" sub with F3 = 20Hz
                        Madison-D and Madison-R - Tang Band W4-1720 + Vifa BC25SC06 or Beston RT003C (TM and MTM)
                        Jeffrey - Tang Band W5-704D + Beston RT003C
                        Jasmine - Fountek FW146 + Fountek NeoCD3.0 Ribbon in Pioneer BS21 Cabinet

                        Comment


                        • #13
                          Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

                          Originally posted by jsr View Post
                          What a coincidence as a couple of days ago, I was going to post a thread asking if anyone has any data with the OT19 in a waveguide, and my desire was for a small 4"ish waveguide at that.
                          These look perfect! Well they be available for sale or just one offs?
                          Also, how do you attach the tweeter to the back if the waveguide?
                          Thanks and great work!
                          As far as attaching the tweeter a dab of silicone on each side would be enough. It fits snug in the guide. All you need is something to keep it from falling out. Small dabs would make it easy to remove if you need to.

                          They are available. I can do them in clear, satin black or gloss black. They could also be painted any color. For the satin or gloss black with the base plate and ring to mount the tweeter and the holes drilled for mounting I would say $40 a piece. If anyone is interested PM me.

                          This is the satin black that I used for the CSS LS25X guides. Click on the image to enlarge it.
                          Click image for larger version

Name:	IMG_20120618_144501.jpg
Views:	1
Size:	96.6 KB
ID:	1142542

                          This is the gloss side on the back.
                          Click image for larger version

Name:	IMG_20120618_144451.jpg
Views:	1
Size:	94.6 KB
ID:	1142543

                          Dave
                          http://www.pellegreneacoustics.com/

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

                          Comment


                          • #14
                            Re: Vifa OT19NC00-04 3/4" in a 4 1/16" Waveguide

                            I could provide a Vifa NE19 and NE25 if you are interested.
                            ~Brandon
                            Please donate to my Waveguides for CNC and 3D Printing Project!!
                            Please donate to my Monster Box Construction Methods Project!!
                            Soma Sonus

                            Comment


                            • #15
                              Dan N.

                              Comment

                              Working...
                              X