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  • Design Using Leftover Drivers

    Hi,

    I'm hoping someone can help me with designing a floor standing speaker using unused woofers, tweeters and full range speakers i currently have.

    In a nutshell i had major foot surgery that went wrong a few years back so I couldn't work for a couple of years and to fill my time i started building random speaker kits. As I live in Australia it was quite expensive so i ordered bulk and now that i have built a heap they are sitting in storage not getting used, I was going to try and sell some but everyone just wants a portable Bluetooth these days and i gave some to family..

    I built the Overnight Sensations, Classix 11, Dayton BR1, The Blues", 2x random boombox style and a set of full range computer speakers using Dayton RS-100, i also have subwoofers and 3.5" drivers not used.

    Now to my point, i want to use as many of the drivers as I can so I'm thinking a 3 way design in a large floor standing speaker. I enjoy the woodworking side of things but i have absolutely no idea of how to design a cross over or cabinet to suit different drivers..

    I was thinking of keeping the "Blues" complete so the drivers i have available that i would like to use are:

    Dayton Audio DC28F-8 Tweeters x4
    Dayton Audio DC160-8 Woofers x4
    Dayton Audio RS100? Full Range x2
    Peerless TC9FD18 Full Range x2

    Can anyone help me with this or give me any advice as it just seems like a waste having new parts not getting used.

    Thanks

  • #2
    MTM with 6" woofers and DC28F tweeters. Crossover may be under Dayton D3. Nice combo for what you have.

    Comment


    • #3
      Thanks for the reply. So you would recommend using 2 mids and 1 tweeter rather than 1 mid 1 tweeter 1 full range per side? Any reason for that? Would that essentially become a Dayton BR1 MTM?
      When you say "Crossover may be under Dayton D3" what do you mean by that?

      Comment


      • #4
        That combo has been around for about 20 years, I built it as my first diy speaker set. It is so old that I could not find the crossover but I am sure that someone on the forum has it. I was very happy with it. Dayton DIII was the name given by the designer Wayne J. I am sure I have it somewhere if no one posts it.

        Comment


        • #5
          http://projectgallery.parts-express....cts/the-d-iii/

          Comment


          • #6
            Can you find out if your RS100 speakers are 4ohm or 8ohm?
            If the sticker/label is missing, usually they'll read around ~3ohm on any cheap DC multimeter for the 4ohm version or ~6ohms for the 8ohm version.
            My first 2way build

            Comment


            • #7
              Originally posted by NUTSACK View Post
              So you would recommend using 2 mids and 1 tweeter rather than 1 mid 1 tweeter 1 full range per side? Any reason for that?
              Cost/complexity of crossover is a consideration. The full range might not be needed depending on how well the woofers match up to the tweeter - I haven't taken a look at the frequency plots for these. MTM sort of limits the complexity to that of a two way.

              You might be able to use the full range for midrange duties and pair it up with a tweeter and two woofers per side. Needs some simulation work to see if it'll work as you be essentially depending on baffle step to aid the low sensitivity of that full range - but it might work.

              Comment


              • #8
                That combo has been around for about 20 years, I built it as my first diy speaker set. It is so old that I could not find the crossover but I am sure that someone on the forum has it. I was very happy with it. Dayton DIII was the name given by the designer Wayne J. I am sure I have it somewhere if no one posts it.

                Thanks for finding that, ill have a better look at it later but at first glance it looks smaller than i was wanting and only uses up 6 out of 12 drivers, not that its a deal breaker because all of the hard work has already been done in regards to cross over etc..


                Can you find out if your RS100 speakers are 4ohm or 8ohm?
                If the sticker/label is missing, usually they'll read around ~3ohm on any cheap DC multimeter for the 4ohm version or ~6ohms for the 8ohm version.

                Yes i can, I'll go for a ride to the storage unit later and pull one out to check. I had both versions but used 1 set in some computer speakers that i gave my niece..

                Cost/complexity of crossover is a consideration. The full range might not be needed depending on how well the woofers match up to the tweeter - I haven't taken a look at the frequency plots for these. MTM sort of limits the complexity to that of a two way.

                You might be able to use the full range for midrange duties and pair it up with a tweeter and two woofers per side. Needs some simulation work to see if it'll work as you be essentially depending on baffle step to aid the low sensitivity of that full range - but it might work.

                YES! This is what i was thinking, it would look good and use up some of these drivers and most importantly hopefully put out a lot of sound. Which full range are you referring to, the Dayton or Peerless?


                I appreciate the help so far and hopefully can get something to work here..

                Comment


                • #9
                  Originally posted by NUTSACK View Post
                  Which full range are you referring to, the Dayton or Peerless?
                  Either one. The Dayton appears to have a slightly smoother response on paper.

                  Comment


                  • #10
                    Originally posted by LOUT View Post
                    Can you find out if your RS100 speakers are 4ohm or 8ohm?
                    If the sticker/label is missing, usually they'll read around ~3ohm on any cheap DC multimeter for the 4ohm version or ~6ohms for the 8ohm version.
                    The RS-100 are 4 ohm..

                    Comment


                    • #11
                      You could use the Silkie, RS100-4 and pair of DC160 as a small TMWW.
                      I think it would work...
                      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*

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                      http://techtalk.parts-express.com/blog.php?u=4102

                      Comment


                      • #12
                        I love how clean and smooth the Peerless TC9FD18's are but they're just not sensitive enough to work with the other drivers. I would agree with both Howard and Wolf... the easy road is build the D3 MTM's with a silkie and two DC160's per side with Wayne's box design and xo. Or have a go at the more difficult road and build a TMWW as Wolf suggested (would need a xo developed).
                        Craig

                        I drive way too fast to worry about cholesterol.

                        Comment


                        • #13
                          Originally posted by PWR RYD View Post
                          I love how clean and smooth the Peerless TC9FD18's are but they're just not sensitive enough to work with the other drivers...
                          I was thinking the same thing. If OP could get another pair of TC9FD18's, would a WMTMW work? Still a db less sensitive than the single RS100-4, but would meet the "large floor standing 3-way" goal.

                          Comment


                          • #14
                            Without crunching any numbers to be sure, my gut says it could work very well. A tall, narrow, floor standing WMTMW would be fun! Or make it a MTMWW about 8" wide and 40" tall. Huge bang for the buck
                            Craig

                            I drive way too fast to worry about cholesterol.

                            Comment


                            • #15
                              So I think its viable to head in this direction:
                              Click image for larger version  Name:	Cabinet Design.PNG Views:	0 Size:	439.1 KB ID:	1475912

                              Cabinet
                              The two DC160 woofers are sitting in 22L net volume which will give you around a 43Hz f3. They really cant dig any lower than that. As drawn here the net volume is around 26L but that is not accounting for crossover, drivers etc. That bottom section can be altered to adjust the volume.

                              The woofers are also limited to a pretty small x-max of 3.2mm so in this configuration they will take about 35watts max and produce roughly 103db at 50Hz. Content below 35hz will quickly bottom these out but that's pretty standard.

                              The port is designed around the Holman 65mm PVC DWV pipe you can get from Bunnings here in the land of oz which is actually 69mm outer with a 63.6mm internal diameter. To tune the 22L cabinet to 42Hz requires 198mm in length and keeps your port velocity to just under 20m/s at maximum output. The port terminus on the baffle side should be rounded over. The exact final length of the port needs to be tested once the cabinet is constructed - I always cut tubes a little long, test, and then adjust - its highly likely the final length wont be the predicted 198mm (its usually not).

                              Top and bottom angled panels along with the filling are there to eliminate standing waves. The walls and rear of the cabinet should also be lined with felt or foam.

                              The midrange is sitting in around 2L which should be majority stuffed.

                              Why is the midrange at the top? Simpler cabinet design that gives an angled internal top to help with standing waves and it allows for tighter grouping of all the drivers. It also keeps the tweeter away from yet another edge aiding in reducing diffraction. It serves no other scientific purpose.

                              Crossover:
                              I've put each of the supplied frequency plots for these drivers through Response Blender and added diffraction and baffle step losses. Blender seemed to have some trouble extracting minimum phase so hopefully the minimum phase option in vituix has compensated (it was complaining phase information was missing - not sure if anyone else has had this problem before with Blender?)

                              DISCLAIMER: This is by no means a final design - it is a starting point. Custom designs really need to have final measurements (frequency and impedance) taken with drivers in the cabinet before the crossover can really be completed. However, based on the modelling and information available this combination of drivers seems workable. The only concern here is that this configuration is definitely a 4ohm nominal speaker and needs an amp that is very happy with that load. An 8ohm home theatre receiver type amp will not really like these (then again I've seen commercially available brand name home theatre speakers with close to 2ohm minimums before!).

                              Any final crossover design also needs to consider the measured off axis responses which I have not considered here in this example.

                              I also don't have any experience with the Dayton tweeter - based on its specs the 2K crossover point appears ok to me but someone who has used it before may advise a steeper slope or high crossover point for added protection - naturally, that would completely change this crossover if needed.

                              The midrange already has to be tamed a little here so I don't think the addition of a second midrange serves any purpose. Overall SPL of the system is not limited by the midrange in this case.

                              Click image for larger version  Name:	Crossover_Schema.png Views:	0 Size:	22.8 KB ID:	1475910

                              Click image for larger version  Name:	Crossover.png Views:	0 Size:	391.0 KB ID:	1475911


                              Comment


                              • Geoff Millar
                                Geoff Millar commented
                                Editing a comment
                                The XO point for the Dayton DC28F should be fine: it's been crossed anywhere from about 1500Hz (Tritrix) to 1700 Hz (Dennis Murphy's BR-1 'Murphy Blaster' mod) and higher, of course.

                                The Tritrix is a second order, IIRC the MurphyBlaster is third order.

                                Geoff
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