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  • Outdoor Speakers

    I am in the process of building a pair of speakers that I started planning late last year. These are going to be my first speaker design after building Continuums and a 15" Ultimax sealed subwoofer. I've been doing a lot of reading tyring to learn about crossover design. I'm almost to that point. I had a few goals for this project.

    1) somewhat inexpensive parts since it's my first speaker design and will be exposed to the elements.
    2) poly woofer and sealed cabinet to help protect it when outdoors
    3) I wanted to try out controlled directivity with the SEOS waveguide.

    For Christmas I received a pair of waveguides, Dayton DC28F-8 "silkie" tweeters,and Goldwood 8024 Woofers. Since my AV cabinet project was still ongoing and things are busy in our house with 3 under 3, it took some time before I was able to start. I measured the drivers as best I could to confirm they were close to the published specs using REW.

    The cabinets are 10.5" wide, 12" deep, and 15 3/4" tall. I decided to include an additional element of expirementation, which is the use of constrained layer dampening. This was done by cutting two slightly oversized pieces of 3/8" MDF and gluing them together with a synthetic rubber caulk called Big Stretch. Form this, we made the cuts for our panels.

    After building (but not finishing) the cabinets and having issues with my rigged up measurement box, I decided to go ahead and purchase DATS. I expect this will help me quite a bit. I've been able to measure the frequency response of each driver, but I don't have impedence in the cabinets. I've started work on finishing the cabinets using davepellegrene's trench seam method. Bondo is crazy tough to work with. It turns into a rubber consistency that won't spread only about 30 seconds after mixing.

    Without further ado, here are some pictures of the build process and tweeter response in the waveguide.

    EDIT: Pictures uploaded.
    Last edited by bjaurelio; 07-29-2018, 09:56 PM.

  • #2
    Measurement photos

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    • #3
      Originally posted by bjaurelio View Post
      Bondo is crazy tough to work with. It turns into a rubber consistency that won't spread only about 30 seconds after mixing.
      If that is the case you are using way too much hardener. With the proper mixture you should have several minutes before it starts to harden. Too much hardener also makes it much more difficult to sand. If you have an auto parts place close by I would recommend looking for the Evercoat brand of fillers. They are much easier to work with than standard Bondo.

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      • #4
        30 seconds was a bit of an exaggeration. It still only seemed like it was about a minute and a half even when I used very little hardener. I had a decent amount left in the tube after I used up the can. Like everything in life, it's going to take more practice to get better at working with it.

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        • #5
          Lot of bondo to sand off. Dave Pellegrene's method is to fill the routed seams only, not put a coat over the whole cab. Good luck.

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          • #6
            When I first measured my speakers to design the box, I had a cheap and poorly assembled setup, which I realized when connections started coming loose when I went to get impedance measurements in the box for the crossover design. Subsequently I purchased DATS, which was much easier to use. I not had s problem with much higher Qts drivers than i realized. Running my newly measured ts parameters through unibox yielded a Qtc of 1.19. my solution is to add an aperiodic vent. I bought a pair of drain caps from Lowe's for a little over $3 each and a 4 pack of 1" foam sheets from Walmart for $7 (cheapest 1" project foam i could find). This weekend I'll have to route holes for the vents. It's a good thing the rear is removable on my speakers.

            Once I reduce the picture size to upload, I'll add pictures of my vents.
            Attached Files

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            • #7
              Great idea on the DIY aperiodic vents Look forward to seeing more pics!
              SEC DIY 2014 Speaker Show is on! *November 8th*
              Wanna win a set of Newform Research R30 ribbons?!?!
              SEC DIY 2014 Thread

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              • #8
                Originally posted by bjaurelio View Post
                ...1) somewhat inexpensive parts since it's my first speaker design and will be exposed to the elements.
                2) poly woofer and sealed cabinet to help protect it when outdoors...
                Curious to usage: Portable or Permanent Mount?
                Protective Covers? ( when not in use )

                "Not a Speaker Designer - Not even on the Internet"
                “Pride is your greatest enemy, humility is your greatest friend.”
                "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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                • #9
                  Originally posted by Sydney View Post
                  Curious to usage: Portable or Permanent Mount?
                  Protective Covers? ( when not in use )
                  They will be portable but usually hung under the eaves on hooks. No cover is currently planned. It's a good idea I should investigate, doubly so now that I added the aperiodic vents with just a basic foam filter.

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                  • #10
                    Originally posted by bjaurelio View Post
                    ... It's a good idea I should investigate, doubly so now that I added the aperiodic vents with just a basic foam filter.
                    Standard Practice for Outdoor Venue Speakers ( we get dew every night ). Weatherproof covers are not too pricey
                    "Not a Speaker Designer - Not even on the Internet"
                    “Pride is your greatest enemy, humility is your greatest friend.”
                    "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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                    • #11
                      After getting some assistance here and in the Facebook DIY Loudspeaker Project Pad group, I made a measurement with both speakers wired to get a more accurate Z axis offset. Using minimum phase frd files, Y offset from tape measure, and Z offset that best matched my frequency response measurement with both drivers wired in parallel I now have what I believe is going to be my first crossover build. After I put it together I'm sure it will need some tweaking, but I'm optimistic it will be a good start.

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                      • #12
                        Originally posted by bjaurelio View Post
                        Running my newly measured ts parameters through unibox yielded a Qtc of 1.19.
                        FWIW, running with a Q that high for a small sealed speaker that's going to be suspended in open air outdoors is not such a bad idea. It might even sound better.


                        Brian Steele
                        www.diysubwoofers.org

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                        • #13
                          Our patio is surrounded on 3 sides by the house (it's off the sunroom with exterior walls on the sides from the garage and master bed/bath), so it will get more reinforcement than most outdoor speakers. I've brought it down some where I think there's a good compromise.

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                          • #14
                            In yet another error I had to correct, my close mic measurements were not valid because I forgot to change the speaker settings on the AVR. They were set to small with an 80hz crossover to the subwoofer. Of course the subwoofer was off for the measurements. I took new ones tonight. I don't think it changes the crossover. The only way to flatten it out more would require a significant increase in crossover components. The response reminds me a little of what I remember reading about acoustic scaling when I built my Continuums. This is based on the sole data point of knowing it involves a dip then hump in the bass response. If that makes it sound better with placement close to a wall, it should help the speakers.

                            Click image for larger version

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