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Would it be possible to use the Eminence Legend BP122 driver for a Sealed Subwoofer?

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  • Would it be possible to use the Eminence Legend BP122 driver for a Sealed Subwoofer?

    Just wondering if this 12" woofer could be used as a subwoofer (for music only) in a sealed cabinet or is this just wishful thinking? It is designed for a bass guitarist. By looking at the specs it looks possible, but maybe not practical? If not this driver then what Eminence 12" +- 3" subwoofer would you use?

    https://www.parts-express.com/eminen...-ohm--290-4810

  • #2
    How big of a cabinet do you really have room for?

    That thing needs about 5 cu ft to get low enough as a sub-woofer . . .

    Comment


    • #3
      Eminence drivers are pro-sound drivers, which means they trade off low frequency extension for high sensitivity. Look elsewhere. You don't have to go far, the DaytonDCS 305-4 Classic 12 will give a 40Hz F3 in 2.5 cu ft sealed for a lower price.
      www.billfitzmaurice.com
      www.billfitzmaurice.info/forum

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      • #4
        Originally posted by Steve Lee View Post
        How big of a cabinet do you really have room for?

        That thing needs about 5 cu ft to get low enough as a sub-woofer . . .
        What about in a vented design?

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        • Steve Lee
          Steve Lee commented
          Editing a comment
          You really need to listen Bill - he is pro at this.

      • #5
        WinISD ( linearteam.org -sc ) thinks you could put it in a 4cf box w/a 4"id x 5" long port (Fb in the low 30s) and get "about" 40Hz out of it.
        Seal up the port and you get an F3 more like 50Hz (w/a "Q" near 0.80).

        At 50Hz it'll hit Xmax @ 45wRMS. Vented, it'll take 60w down below 30. (I'd have to go vented on this one. Even @ 60w it CAN do almost 110dB.)

        Comment


        • #6
          You have not said what use you have in mind. Sub for an electric keyboard on the road, or one for your living room? Totally different questions. Totally different answers.

          Are you looking at Eminence drivers because you are still concerned with country of origin? Some guitarist said they were killer?
          https://www.parts-express.com/pedocs...tion-guide.pdf

          They do make subs for the road. Their 21 inch is killer, but also $800 and they suggest between 6 and 14 cu ft cab for 130 dB. Lab 12C may be better for use in the home.

          Download WinISL and learn to use all it's graphs. Model all the possible box alignments, sealed, ported, BP4 and BP6.

          FWIW, an F3 in a sealed box of 50 Hz, may not be a bad target for use in a small room, but still a poor choice in drivers. If you have that driver, grab a couple sheets of PB and make one to see. You learn a lot more by building one than asking the forum to do all your work.

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          • #7
            Originally posted by tvrgeek View Post
            You have not said what use you have in mind. Sub for an electric keyboard on the road, or one for your living room? Totally different questions. Totally different answers.

            Are you looking at Eminence drivers because you are still concerned with country of origin? Some guitarist said they were killer?
            https://www.parts-express.com/pedocs...tion-guide.pdf

            They do make subs for the road. Their 21 inch is killer, but also $800 and they suggest between 6 and 14 cu ft cab for 130 dB. Lab 12C may be better for use in the home.

            Download WinISL and learn to use all it's graphs. Model all the possible box alignments, sealed, ported, BP4 and BP6.

            FWIW, an F3 in a sealed box of 50 Hz, may not be a bad target for use in a small room, but still a poor choice in drivers. If you have that driver, grab a couple sheets of PB and make one to see. You learn a lot more by building one than asking the forum to do all your work.
            Basically, I'm looking for a DURABLE subwoofer driver(s) for a workshop / garage environment to augment a 2-way design I'm working on. Also, it would be nice if it had a sensitivity >= 86dB. Living on a homestead in a very tough climate I often don't have the resources of time, funds and skill set for proper maintenance & fixing of things that break down. I have a list a mile long right now for such things & am always looking for durable and high quality products that are not overly priced to avoid such failures. Ultimately, as I get older, I just don't have the time nor the patience for it.

            The first thing I look at when I am thinking about purchasing a product is how much/many resources will it take to maintain it. If it shows the slightest bit of low quality I walk, no run, away. I'm getting pretty good at picking out the high quality from the low quality products. If I can actually get it in my hands I can show you where something will fail. As an engineer that's what we often study, failures.

            I would rather work on my hobbies than maintain / fix things and at the moment have almost no time for the former. Honestly, I would rather design/build a 3-way system, but I lack the design skills as this is my first design & it is pretty well unanimous that your first design should be a 2-way. And I want to do my own design just for the fun of learning about it. Hope that helps.

            And thanks for all the comments, especially Bill; I had not realized subwoofer driver's sensitivity and low-end extension were inversely proportionate, so yes I agree I was looking in the wrong place. And I think either Qts or Fs/Qes is inversely proportionate to driver sensitivity? Although Eminence does make the LAB12C, which I don't think is in their pro line up. Well at least PE doesn't put it there, among 4 other Eminence subwoofers. Oh, I should say my budget is around $150 for a driver or driver(s), but willing to up the ante if the quality / durability is there.

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            • #8
              Well, I have 4 subs. The newest is at least 10 years old. ( 2 Peerless XLSS, 1 Dayton RS, one Dayton Titanic which I think was made by Eminence. ) Never had to do "maintenance " on them. If you are going into a un-heated space, might look at aluminum or poly drivers, or at least not raw paper. Pick a driver designed to be a sub. Pick realistic goals. Music in a shop does not need 18 Hz special effects.

              "Pro" line means it is for PA use. Public Address, i.e. sound reinforcement. That has nothing to do with quality or durability.

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              • #9
                The LAB 12 is a pro-sound driver. It was created specifically for use in the Danley designed LAB Horn pro-sound sub. I specify it in a number of my horn loaded pro- sound subs as well. It can be used in direct radiators, but there are many far better choices for a sealed or ported cab.
                I'm assuming you haven't software modeled the BP-122. If you did, and modeled the Classic 12 as well, you'd find that as a sub the Classic 12 works better, in a cab 1/2 to 1/3 the size that the BP122 needs, and thanks to having 9.3mm xmax, versus 6.2mm for the BP122, below 60Hz it will go louder as well.

                You mention a two-way. Sub woofer drivers aren't suitable for two-ways, unless you can find a tweeter than can go down to at least 500Hz.
                www.billfitzmaurice.com
                www.billfitzmaurice.info/forum

                Comment


                • #10
                  Originally posted by billfitzmaurice View Post
                  The LAB 12 is a pro-sound driver. It was created specifically for use in the Danley designed LAB Horn pro-sound sub. I specify it in a number of my horn loaded pro- sound subs as well. It can be used in direct radiators, but there are many far better choices for a sealed or ported cab.
                  I'm assuming you haven't software modeled the BP-122. If you did, and modeled the Classic 12 as well, you'd find that as a sub the Classic 12 works better, in a cab 1/2 to 1/3 the size that the BP122 needs, and thanks to having 9.3mm xmax, versus 6.2mm for the BP122, below 60Hz it will go louder as well.

                  You mention a two-way. Sub woofer drivers aren't suitable for two-ways, unless you can find a tweeter than can go down to at least 500Hz.
                  It will be a 2.1 systems w/ stand alone subwoofer . Thanks

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                  • #11
                    diysg has some woofer remnants under "moving sale" tab. Most of his woofers are from Eminence.

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                    • #12
                      Sorry if you already mentioned it and I missed it, but do you already have the other speakers (the 2way woofer+tweeter) picked out?
                      Likewise, what'll you be using to power the 2ways and what'll be powering the subwoofer?

                      Knowing these might help folks guide you toward a sub that can match the 2ways using that sub-amp's power output without falling short, over-spending or going far larger-than-necessary.

                      A Dayton Classic Sub / DCS, like already mentioned, should be plenty for rocking a garage though. Even the smaller/cheaper DCS255 10inch should be able to hit 110-112db from 150-200watts while reaching down to 35hz in a modest 1.5ft-cu box....and they're cheap enough for your budget to grab two of them if you decide you need to make teeth rattle.
                      If something closer to 105db would be plenty for keeping up with the 2ways, then you could reach ~35hz F3 in a smaller 1ft-cu box using a cheaper 8inch DCS205 or a super affordable SD215a-88 (or five...because they're cheap). The DCS have more XMAX and wattage-handling headroom than the cheaper SD's though.
                      I don't think the larger 12inch DCS315 get's much louder at around 112-114db, but it DOES happily reach a little lower (down a bit below 25hz if you give it a really large box) while the 10inch starts to lose enthusiasm below 30-35hz. Not a big deal for most music, but the 12inch should be a nicer option for movie sound-effects.



                      If you'll be designing the whole thing mostly by yourself, a 2way should be more forgiving than a 3way (largely from a more simple crossover design).
                      On the other hand, if you're okay with some woodwork and soldering and aren't opposed to using an established/vetted design, there are plenty of excellent 3way builds that you could pick one to use as a kind of shortcut for drivers/parts-list, crossover-design and some cabinet size/shape planning. That way you'd still be buying and building everything yourself while getting a known and tested end result.
                      My first 2way build

                      Comment


                      • kushtekaa
                        kushtekaa commented
                        Editing a comment
                        I'll probably power it with the new Lepai 2.1 plate amplifier (runs dual TPA 3118 chips). I already have some of these chip amps, generally the higher quality ones, like the Texas Instrument EVM boards & really like them. It would be nice to use what I already have, but the plate amp already has the subwoofer cross built-in & a 100 Hz high pass filter, which would work very well with my 2-way design.

                        From what I've read with these TPA 3110, 3116, 3118 is to use a good power supply or a Capacitance Multiplier on the power source.

                    • #13
                      Originally posted by kushtekaa View Post
                      I'll probably power it with the new Lepai 2.1 plate amplifier (runs dual TPA 3118 chips).
                      Unless I'm looking at the wrong plate-amp, those claim 30right+30left+60sub watts at 4ohm (doesn't appear to specify a separate ohm-rating for the sub output, so I'm guessing it's 4ohm minimum for each?). That sounds like you could easily go with something like the very affordable 8inch Dayton SD215a-88 without much fear of it getting hurt. A larger woofer should leave you more headroom for keeping ultra-low notes below XLIM when fully cranked, but I'm not sure that's really a problem with the cheaper classD boards and their somewhat inherent highpass...the amp itself might naturally protect the sub from ultra-low FR as-is. Hopefully someone better versed in those boards/amps can share if they have some high-pass happening at the sub (either on purpose or via cheap components lacking at the low FR).

                      Not saying a larger, louder or fancier sub-driver wouldn't also work really well...it just sounds like it might be a little wasted if powered from a 60watt@4ohm amp.
                      The SD series is a little more efficient watt-per-watt at the expense of not handling as much power and also needing a larger box to get low compared to the DCS and RSS/Ultramax Dayton subs, but that seems like a good fit for something that won't need to handle hundreds of watts and won't need to blend into your familyroom.


                      EDIT: I think the more expensive version that includes a power brick might be limited to around 15+15+30watts or less because of the wimpy brick....though it might depend on whether the amp HighPasses the stereo speakers or runs them fullrange.
                      Does anyone know if passing the lows only to the sub and mids/highs only to Left/Right means the sub and L/R gets to split PS wattage more like a 3way passive instead of dividing the power between amps?
                      Last edited by LOUT; 11-13-2020, 01:03 PM.
                      My first 2way build

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                      • #14
                        Do the simulation in WinISD. you may find 60W won't cut it.

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