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RS2-8T MTM RS225 RS28A Project

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  • RS2-8T MTM RS225 RS28A Project

    So this is my 7th speaker building project since Feb! My brother recently visited and we spent some time listening to some of the speakers I've built, he was blown away with enthusiasm and insisted I build him a pair of speakers for his living room. I loved the Dayton RS225 in my RS4 project and have really been wanting to use it in an MTM for a pair of relatively compact towers with good bass response.

    I know this isn't a popular configuration but I really wanted to try it after the success I had with the PS2 speakers I built. Also been wanting to try out the RS28A tweeter. Since my brother would be running these off a receiver active crossover was out. The Drivers Again the drivers in each tower are a pair of Dayton RS225-8 MTM around a Dayton RS28A

    The Enclosures About 40" tall and 12" wide, construction is with 3/4" Maple plywood. Bracing is conservative but effective, final enclosure volume is 2.6 (sorry typo I originally typed 2.2) cubic feet, 4" port is tuned to 30hz (verified) and features flares on the inside as well as outside. Stain is Minwax "natural" which gives the same effect as mineral oil visually with Minwax Semigloss poly spray.

    The Crossover I used the simplest passive I could get away with, 2k hz and 12db/octave, I ended up padding the tweeter 2db and used a Zobel on the woofers. I could have spent more time on it but I believe it's 90% of the way there and I know they will fill the intended application very well.



    Measurements I did 3 measurements, all on axis with the tweeter, in room about 6 feet from one speaker. The 3 graphs are with the bass treble knobs turned all the way each way.



    Finished Result These turned out very nice I feel, my bro wanted the natural look and I like it.



























    Listening Impressions I was really blown away how good these sound and the bass response were shocking! The bass capabilities of the RS225 continue to astound me, considering how little excursion they're capable of and jay they're not a subwoofer, they are one of the best bass producing woofers I've used. These towers easily match many 12" pairs of subwoofers in bass and have no trouble going down below 30hz in room. Imaging is excellent and the RA28A sounds well dampened and with no unruly sibilance, it's very well behaved. I did a lot of the crossover tuning/experimenting with miniDSP initially before testing the passive, and with a few PEQ tweaks these really come alive! As is they sound very good but do need a little work with music that is heavy with female vocals especially pop music.

    The Dayton drivers hold up to drivers costing 2-3 times as much, for less than $320 in drivers these towers sound incredible. Really like how these turned out and am struggling with giving them away this weekend. Considering another set for myself as well. Javad
    Last edited by JavadS; 05-26-2016, 09:14 PM.
    --
    Javad Shadzi
    Bay Area, CA

    2-Channel Stereo system in the works with Adcom components and 4-way towers

  • #2
    Little video of them playing https://vimeo.com/168152236 Sent from my iPhone using Tapatalk
    --
    Javad Shadzi
    Bay Area, CA

    2-Channel Stereo system in the works with Adcom components and 4-way towers

    Comment


    • #3
      How is the woofer resonance? Can you do a woofer response measurement with xover by itself?
      I'm betting it's pretty strong,
      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


      • #4
        Originally posted by Wolf
        How is the woofer resonance? Can you do a woofer response measurement with xover by itself? I'm betting it's pretty strong, Wolf
        What measurement would you like? Happy to do it, and you're saying the woofer w/o the tweeter or? Sent from my iPhone using Tapatalk
        --
        Javad Shadzi
        Bay Area, CA

        2-Channel Stereo system in the works with Adcom components and 4-way towers

        Comment


        • #5
          This is a dats measurement fwiw Sent from my iPhone using Tapatalk
          --
          Javad Shadzi
          Bay Area, CA

          2-Channel Stereo system in the works with Adcom components and 4-way towers

          Comment


          • #6
            How did you fit a 14" long vent into an 11" deep box (w/out a bend)? If there IS one, I can't see it.

            Comment


            • #7
              Originally posted by Chris Roemer View Post
              How did you fit a 14" long vent into an 11" deep box (w/out a bend)? If there IS one, I can't see it.
              Chris I think he stated 4" could be length or diameter.

              Comment


              • #8
                Originally posted by Chris Roemer
                How did you fit a 14" long vent into an 11" deep box (w/out a bend)? If there IS one, I can't see it.
                4" diameter, port length is 5" long, see verified tuning freq of 30hz above. To add, originally winISD suggested that a 5" port would give 40hz which is what I was targeting but it ultimately resulted in 30hz and I'm very happy with the way the enclosure sounds.
                --
                Javad Shadzi
                Bay Area, CA

                2-Channel Stereo system in the works with Adcom components and 4-way towers

                Comment


                • #9
                  Javad-
                  I mean the FR plot of the woofer with it's xover, and the tweeter and it's xover disconnected. I know you said it was as simple as possible, and should meet the recipients needs, but I can imagine how much of a ringing headache that the RS225 can yield being the aluminum resonance is quite horrendous.

                  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


                  • #10
                    Yup. Something SEEMs amiss there. Even before T/S parms, you could still tune a 2.5cf box to 41Hz w/a 4"id x 5" long port tube.
                    T/S parms just let us predict (model) how a particular driver will act in a certain sized box w/a certain tuning. The driver itself can't change the Fb (box tuning).

                    I can't SEE what's up w/that, but I DO see that DATS has verified your Fb @ 30Hz. Curious. Your Z-plot looks pretty normal (not like you've got any kind of leaky driver seal or anything - it wouldn't look the way yours does). It wouldn't even matter if you powered only 1 woofer or both, UNLESS you powered only one and the other acted like a PR, changing the box tuning. ?

                    If you have indeed tuned a 2.2cf box to 30Hz using a (rather) short length of 4" tubing, THAT would be a W-A-A-Y larger "game-changer" than all the stuff rgs uppercut is working on.

                    Comment


                    • #11
                      Originally posted by Chris Roemer
                      Yup. Something SEEMs amiss there. Even before T/S parms, you could still tune a 2.5cf box to 41Hz w/a 4"id x 5" long port tube. T/S parms just let us predict (model) how a particular driver will act in a certain sized box w/a certain tuning. The driver itself can't change the Fb (box tuning). I can't SEE what's up w/that, but I DO see that DATS has verified your Fb @ 30Hz. Curious. Your Z-plot looks pretty normal (not like you've got any kind of leaky driver seal or anything - it wouldn't look the way yours does). It wouldn't even matter if you powered only 1 woofer or both, UNLESS you powered only one and the other acted like a PR, changing the box tuning. ? If you have indeed tuned a 2.2cf box to 30Hz using a (rather) short length of 4" tubing, THAT would be a W-A-A-Y larger "game-changer" than all the stuff rgs uppercut is working on.
                      Volume is 2.6 not 2.2 that was a typo, hth Javad Sent from my iPhone using Tapatalk
                      --
                      Javad Shadzi
                      Bay Area, CA

                      2-Channel Stereo system in the works with Adcom components and 4-way towers

                      Comment


                      • #12
                        Originally posted by Wolf
                        Javad- I mean the FR plot of the woofer with it's xover, and the tweeter and it's xover disconnected. I know you said it was as simple as possible, and should meet the recipients needs, but I can imagine how much of a ringing headache that the RS225 can yield being the aluminum resonance is quite horrendous. Later, Wolf
                        Gotcha will try to do that tonight. Audibly there are no nasty ringing or resonances or any brightness or sibilance that I can hear that would render this speaker not smooth and clean and clear sounding, but I'll be happy to do the measurements. Sent from my iPhone using Tapatalk
                        --
                        Javad Shadzi
                        Bay Area, CA

                        2-Channel Stereo system in the works with Adcom components and 4-way towers

                        Comment


                        • #13
                          No intensions of taking the focus off of your speakers but that is one sexy group of Adcom components you have there.

                          Comment


                          • #14
                            Originally posted by rickyj
                            No intensions of taking the focus off of your speakers but that is one sexy group of Adcom components you have there.
                            Hah glad you like rickyj! =) Sent from my iPhone using Tapatalk
                            --
                            Javad Shadzi
                            Bay Area, CA

                            2-Channel Stereo system in the works with Adcom components and 4-way towers

                            Comment


                            • #15
                              Originally posted by Wolf View Post
                              Javad-
                              I mean the FR plot of the woofer with it's xover, and the tweeter and it's xover disconnected. I know you said it was as simple as possible, and should meet the recipients needs, but I can imagine how much of a ringing headache that the RS225 can yield being the aluminum resonance is quite horrendous.

                              Later,
                              Wolf
                              Here you go Wolf
                              --
                              Javad Shadzi
                              Bay Area, CA

                              2-Channel Stereo system in the works with Adcom components and 4-way towers

                              Comment

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