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Would this single 18" be enough for an OB?

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  • Would this single 18" be enough for an OB?

    Hi all!

    I'm looking for a new project to build, and suddenly, these drivers went on sale... Dayton Audio 295-036 Pro Woofer, 18"

    I think I paid $140 for 3 of them. NICE!!!!

    Anyway... I wanted to get 4, but Amazon ran out of stock. I can only use a single one per side.

    Do you think that would be enough for an OB speaker, next to a pair of RS-150s, and a Neo3 PDR?


    Line Array: IDS-25 Clone, FE-83.
    2-2.5 Way:
    Zaph Audio's winning entry: ZA5+SB29. - Microliths: RS125+RS28. - Small Bangs: TB W4-1658SB+SEAS 27TBFC/G. - Monoliths: Peerless 830884+SEAS 27TBFC/G.
    3-3.5 Way:Miniliths: SEAS P21/CA21REX+Neo8 PDR+Neo3 PDR. - Megaliths: 2xDayton RS270+2xT-B W4-1337SB+SB29. - ZDT3.5 +: 2xDayton RS180+Dayton RS52+Vifa DQ25. Reflexos: OB 4xDayton RS150 + Neo3 PDR.

  • #2
    You could use the 3rd to reinforce the low end if you wanted.

    Comment


    • #3
      With an OB I prefer to see more than 6mm of xmax but with an sd of 1240cm² it shouldn't take too many of them to fill a good size room. With 97.8db it shouldn't take much power to drive them either.

      I assumed you meant those to be used as a sub but if not, search jhollander he has a fairly simple pink/purple OB with a buyout Titan 15"? woofer that might give you some ideas.
      http://techtalk.parts-express.com/fo...khanspires-but
      http://techtalk.parts-express.com/fo...pico-neo-build
      http://techtalk.parts-express.com/fo...ensation-build

      Comment


      • #4
        "enough" is dependant upon your expectations of low frequency extension and SPL.
        "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
        exactly a Fc 3K for both drivers, anybody can do it." -Xmax

        Comment


        • #5
          Assuming you are DSPing you can get to 36.5 Hz at 100 dB and x-max on a 24 inch flat baffle. The passive roll off is pretty steep with a .33 qts.
          John H

          Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

          Comment


          • #6
            Yes, I'll be using a MiniDSP. I guess it's going to be OK!

            For the price I paid, I'll probably sell the third woofer. For the price they go here, I'll end up with two 18"s for free

            Thanks a lot!
            Line Array: IDS-25 Clone, FE-83.
            2-2.5 Way:
            Zaph Audio's winning entry: ZA5+SB29. - Microliths: RS125+RS28. - Small Bangs: TB W4-1658SB+SEAS 27TBFC/G. - Monoliths: Peerless 830884+SEAS 27TBFC/G.
            3-3.5 Way:Miniliths: SEAS P21/CA21REX+Neo8 PDR+Neo3 PDR. - Megaliths: 2xDayton RS270+2xT-B W4-1337SB+SB29. - ZDT3.5 +: 2xDayton RS180+Dayton RS52+Vifa DQ25. Reflexos: OB 4xDayton RS150 + Neo3 PDR.

            Comment


            • #7
              The specs on that woofer, as would be expected with a pro-sound driver, are the opposite of what you want for an IB, which needs high Qts and long xmax.
              www.billfitzmaurice.com
              www.billfitzmaurice.info/forum

              Comment


              • #8
                I've built a single OB speaker (From 150 Hz on up) and an OB subwoofer (with 4 15" car woofers) .. but never a full range one.


                If the woofers aren't suitable for the project, it's no problem - I got them for a steal , and I can resell them very quickly. But if the Qts thing can be fixed with DSP, and the Xmax is enough, I'll definitely use these drivers...
                Line Array: IDS-25 Clone, FE-83.
                2-2.5 Way:
                Zaph Audio's winning entry: ZA5+SB29. - Microliths: RS125+RS28. - Small Bangs: TB W4-1658SB+SEAS 27TBFC/G. - Monoliths: Peerless 830884+SEAS 27TBFC/G.
                3-3.5 Way:Miniliths: SEAS P21/CA21REX+Neo8 PDR+Neo3 PDR. - Megaliths: 2xDayton RS270+2xT-B W4-1337SB+SB29. - ZDT3.5 +: 2xDayton RS180+Dayton RS52+Vifa DQ25. Reflexos: OB 4xDayton RS150 + Neo3 PDR.

                Comment


                • #9
                  You do not need high qts if you are boosting/ DSPing, it a function of the volume displacement at the particular frequency.
                  John H

                  Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

                  Comment


                  • #10
                    Originally posted by jhollander View Post
                    You do not need high qts if you are boosting/ DSPing, it a function of the volume displacement at the particular frequency.
                    Thanks. Now the question I have is about SPL's. 36.5 Hz seems a bit on the low side.

                    I wish I could have bought 4 of those woofers. I had in my mind a huge WWMTMWW, with 2 18's, 2 8's, 2 4's and a Neo3 per side.
                    Line Array: IDS-25 Clone, FE-83.
                    2-2.5 Way:
                    Zaph Audio's winning entry: ZA5+SB29. - Microliths: RS125+RS28. - Small Bangs: TB W4-1658SB+SEAS 27TBFC/G. - Monoliths: Peerless 830884+SEAS 27TBFC/G.
                    3-3.5 Way:Miniliths: SEAS P21/CA21REX+Neo8 PDR+Neo3 PDR. - Megaliths: 2xDayton RS270+2xT-B W4-1337SB+SB29. - ZDT3.5 +: 2xDayton RS180+Dayton RS52+Vifa DQ25. Reflexos: OB 4xDayton RS150 + Neo3 PDR.

                    Comment


                    • #11
                      Originally posted by fjhuerta View Post
                      Hi all!

                      I'm looking for a new project to build, and suddenly, these drivers went on sale... Dayton Audio 295-036 Pro Woofer, 18"

                      I think I paid $140 for 3 of them. NICE!!!!

                      Anyway... I wanted to get 4, but Amazon ran out of stock. I can only use a single one per side.

                      Do you think that would be enough for an OB speaker, next to a pair of RS-150s, and a Neo3 PDR?

                      No matter what you do, you will not be able to get much bass when using these drivers in an open baffle, even with a huge baffle. Both the relatively low Qts and relatively high Fs are working against you in this application. It does not matter that they are 18" drivers.

                      The in-OB response of the woofer will be much like in "free air", that is the resulting Qts and Fs will be close to their free air values. Since Qts is only 0.33 or so, that means a drooping free air response. On top of that, you get dipole cancellation, more and more of it at lower frequencies. So you have both a drooping free air response, AND you have dipole cancellation with also causes the frequency response to tilt down.

                      The high sensitivity is helpful, and can make up for some of the losses, but you will need a lot of low frequency correction/shaping. This either requires a large inductor ($$$) or an active crossover or DSP.

                      If you can implement the crossover and shaping correctly, and don't mind the response only reaching down to 60Hz or so, these woofers are OK. There are much better options for OB bass, however, and you might consider "loading" the driver in an H- or U-frame, or if you want to go "large" a SLOB. When made large, these type of OB bass systems can make up for some of the losses that a planar OB creates.
                      Charlie's Audio Pages: http://audio.claub.net

                      Comment


                      • #12
                        In many rooms there is so much low frequency gain that you might be surprised how well OB bass works. I know that I was.

                        Here's my suggestion: You have the drivers already. Take a sheet of the cheapest plywood/MDF/chipboard you can find and mount the 18" driver to it. Preferably close to the floor (within a few inches). Mount a couple of shelf brackets to the bottom of the wood to hold the baffle vertical. Add a small full rage driver like the Peerless TC9 (around 10 bucks) and cross over at 300 - 400Hz. Make sure the full range driver is mounted asymmetrically (say 2 inches from the top and 3 inches from the side of the baffle). You now have a reasonably good OB set-up for maybe $50 invested. Now YOU can decide if it's good or not. Since YOU are the one that must be pleased by the results what everyone else thinks matters little.

                        If you decide you like it (even a bit) you can now start tweaking. Change the speaker position in the room (distance from the back wall will have a huge influence). Add "wings" to make it a U-frame. Taper the wings. Add a shelf at the top. Whatever. Since there is no pressure from the driver to deal with you can make all of these mods using cardboard (like from an old box) and staples. Super fast and cheap experimentation. Heck, go hog wild and add a tweeter and go 3-way! If you find a configuration that's a keeper, you can now make a "nice" baffle. If you never find a configuration that you like, you have now learned that OB is not for YOU in YOUR room. Sell the divers and move on. You will have lost almost nothing but time playing around with your hobby.

                        Just my 2 cents...

                        Comment


                        • #13
                          Originally posted by fjhuerta View Post
                          But if the Qts thing can be fixed with DSP, and the Xmax is enough, I'll definitely use these drivers...
                          The too low Qts can be addressed with EQ to get more low end, but as every 6dB of EQ doubles excursion you'll run out of xmax in short order.

                          www.billfitzmaurice.com
                          www.billfitzmaurice.info/forum

                          Comment


                          • #14
                            Originally posted by LIDAR View Post
                            In many rooms there is so much low frequency gain that you might be surprised how well OB bass works. I know that I was.

                            Here's my suggestion: You have the drivers already. Take a sheet of the cheapest plywood/MDF/chipboard you can find and mount the 18" driver to it. Preferably close to the floor (within a few inches). Mount a couple of shelf brackets to the bottom of the wood to hold the baffle vertical. Add a small full rage driver like the Peerless TC9 (around 10 bucks) and cross over at 300 - 400Hz. Make sure the full range driver is mounted asymmetrically (say 2 inches from the top and 3 inches from the side of the baffle). You now have a reasonably good OB set-up for maybe $50 invested. Now YOU can decide if it's good or not. Since YOU are the one that must be pleased by the results what everyone else thinks matters little.

                            If you decide you like it (even a bit) you can now start tweaking. Change the speaker position in the room (distance from the back wall will have a huge influence). Add "wings" to make it a U-frame. Taper the wings. Add a shelf at the top. Whatever. Since there is no pressure from the driver to deal with you can make all of these mods using cardboard (like from an old box) and staples. Super fast and cheap experimentation. Heck, go hog wild and add a tweeter and go 3-way! If you find a configuration that's a keeper, you can now make a "nice" baffle. If you never find a configuration that you like, you have now learned that OB is not for YOU in YOUR room. Sell the divers and move on. You will have lost almost nothing but time playing around with your hobby.

                            Just my 2 cents...
                            Not a bad idea at all!

                            I currently have an OB MTM with a pair of RS-150's and a Neo3 in a panel format. I could easily build an H frame to support the panel, in simple MDF.... if I like it, then I'll paint the panels, etc. If I don't, I sell the drivers...

                            I can also model the woofers... perhaps they could make a killer set of stereo subs if the OB doesn't work out...
                            Line Array: IDS-25 Clone, FE-83.
                            2-2.5 Way:
                            Zaph Audio's winning entry: ZA5+SB29. - Microliths: RS125+RS28. - Small Bangs: TB W4-1658SB+SEAS 27TBFC/G. - Monoliths: Peerless 830884+SEAS 27TBFC/G.
                            3-3.5 Way:Miniliths: SEAS P21/CA21REX+Neo8 PDR+Neo3 PDR. - Megaliths: 2xDayton RS270+2xT-B W4-1337SB+SB29. - ZDT3.5 +: 2xDayton RS180+Dayton RS52+Vifa DQ25. Reflexos: OB 4xDayton RS150 + Neo3 PDR.

                            Comment


                            • #15
                              Stereo woofers, yes. Stereo subs, no. They're pro-sound, they have high sensitivity at the expense of low frequency response.
                              www.billfitzmaurice.com
                              www.billfitzmaurice.info/forum

                              Comment

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