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Lithium

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  • Lithium

    Lithium is a small monitor that doesn't have any idea how small it is.

    Drivers:

    Dayton ND-105-4
    Vifa BC25SC06-04

    Crossover:

    LR4 acoustic 2.4 kHz.

    Dimensions:

    9" tall, 6" wide, 8" deep (same as Overnight Sensations).

    Price:

    Drivers + Crossover = $170 as of 10/15/2012

    Design goals:

    Mike Zisserson's New Horizons and Chris Roemer's Nano Neos have been very well-regarded designs. I liked the potential of the ND-105, but wanted something smaller that could go easily on a wall, shelf, or desktop. Since the small Dayton neo tweeters have increased in price, I thought there might be a better value out there. The Vifa BC25SC06-04 has slight horn loading, that aligns the acoustic center with the ND-105. Lithium was designed to give satisfying musical response by itself in tight quarters, or work well as a home theater satellite - enabling a low enough crossover to minimize subwoofer localization in small to medium rooms.

    Cabinet:

    When DIY Sound Group first introduced the Overnight Sensation flat pack, the woofer cutout for the HiVi B4n was not countersunk. I noticed that the ND-105 would drop in perfectly, so I had my cabinets. The cabinet walls are 1/2" baltic birch. The PE 1" by 4" flared port tunes the cabinet to 47 Hz. The side and back walls are lined with R9 Ultra Touch denim fiber insulation available by mail order from Home Depot. I finished with Minwax cherry gel stain and several coats of wipe-on poly.

    Crossover:

    I wanted to get the crossover frequency low enough that there wouldn't be any off-axis beaming from the woofer or issues with aluminum cone breakup modes, but high enough that the tweeter wouldn't be stressed. I settled on a 2.5 kHz fourth order Linkwitz Riley acoustic target. In order to get that, I had to go 4th order electrical on the ND-105. The very efficient Vifa tweeter took a lot of padding to get down to the level of the ND-105. I estimate about 5 dB of baffle step compensation, which gives a relatively full sound for most placements.

    Measurements:

    The on axis response is flat within +/- 2 dB from the lower limit of accurate gated measurements in my room (200-300 Hz) to 18.5 kHz. The reverse null indicates a crossover point of 2.4 kHz. Off axis, there are no significant flares or other issues. The impedance plot has a minimum of just over 4 ohms at 180 Hz. It doesn't stay below 5 ohms for long, so by commercial standards it would be a 6 ohm design. The saddle between the two low frequency points shows the port tuning frequency of 47 Hz.

    Listening Impressions:

    I won't offer any yet. These will be coming to DIY Iowa 2012 in Grinnell this weekend - so we should have some feedback soon.
    Attached Files
    Last edited by scottsehlin; 10-15-2012, 11:21 PM. Reason: Fixed attachment
    Keep an open mind, but don't let your brain fall out.

    Argon | Helium | Lithium | LithMTM | Hafnium
    Mercury | Matrix | Shrubbery

  • #2
    Re: Lithium

    Here is the impedance plot...
    Attached Files
    Keep an open mind, but don't let your brain fall out.

    Argon | Helium | Lithium | LithMTM | Hafnium
    Mercury | Matrix | Shrubbery

    Comment


    • #3
      Re: Lithium

      Love that little Vifa tweeter. Amazing you can get such solid bass in a box that small.

      I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
      "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

      High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
      SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
      My Voxel min sub Yet-another-Voxel-build

      Tangband W6-sub

      Comment


      • #4
        Re: Lithium

        Gee, what should a guy do if he has almost all the parts including the OS DIY cabs. . . . . ? :D
        I was so much older then, I'm younger than that now.
        OS MTMs http://techtalk.parts-express.com/sh...d.php?t=220388
        Swope TM http://techtalk.parts-express.com/sh...d.php?t=221818
        Econowave and Audio Nirvana AN10 fullrange http://techtalk.parts-express.com/sh...d.php?t=216841
        Imperial Russian Stouts http://techtalk.parts-express.com/sh...=1#post1840444
        LECBOS. http://techtalk.parts-express.com/sh...ghlight=lecbos

        Comment


        • #5
          Re: Lithium

          Nice! I wish I could hear them, but I don't think I can make it to Iowa this year.

          I'm very curious how the ND105-4 fares in that box. The filter looks very interesting as well. I think I might have to try it to see how you did it!
          Isn't it about time we started answering rhetorical questions?

          Paul Carmody's DIY Audio Projects
          Twitter: @undefinition1

          Comment


          • #6
            Re: Lithium

            Originally posted by donradick View Post
            Love that little Vifa tweeter. Amazing you can get such solid bass in a box that small.
            It really is an impressive driver. F3 models at about 51 Hz and I believe it from listening.

            Gee, what should a guy do if he has almost all the parts including the OS DIY cabs. . . . . ?
            I'd say you can't go wrong - but let's see how it fares in that big auditorium in Grinnell.

            I'm very curious how the ND105-4 fares in that box. The filter looks very interesting as well. I think I might have to try it to see how you did it!
            If I ever wind up in your neighborhood or vice versa, we should get a listening session together. The main issue with the filter is that the ND-105 just seems to need a higher order filter to really convince it to do what you want rather than the other way around. The standard notch and tank filters leave too much residual HF content - as the ND-105 tries to be a full-range driver. The tweeter just needs a lot of padding.
            Keep an open mind, but don't let your brain fall out.

            Argon | Helium | Lithium | LithMTM | Hafnium
            Mercury | Matrix | Shrubbery

            Comment


            • #7
              Re: Lithium

              The tiny monitor sounded very good in the large hall in Iowa an was the smallest of the lot there!

              Comment


              • #8
                Re: Lithium

                OK Scott, here's your critique: The Lithium's rocked. They're as good as can be. Enuf said!

                Alright, really there's not much you could possibly do to improve them. As I mentioned to you yesterday, I see some of the stuff that you put together and wonder what you're thinking, then hear what you've done and shake my head in amazement.

                Comment


                • #9
                  Re: Lithium

                  If anyone has these parts "lying around" and you DON'T build this, it will be YOUR loss.

                  I always thought the ND105 required a larger volume cabinet if you wanted to take full advantage of its crazy XMAS. WRONG. Scott proved what can be done with this driver in a minimalist enclosure, and his tweeter choice and crossover design make it a real winner.
                  Bryan K.

                  Midwest Audio Club

                  Speedster | Sub Attachť | The Wildeman | Sean's NLA Towers | CO‹GAR, COUGAR II and CO‹GAR JR | Triton | Lithium | J-Boom | Trym MLTL | Docere MLTL

                  Comment


                  • #10
                    Re: Lithium

                    What gauge is used in the inductors? These look interesting for a bedroom system.
                    My Statement monitors
                    My Piccolatas
                    My LM3886 amp

                    Comment


                    • #11
                      Re: Lithium

                      The 2 mH inductor is 18 Ga. laminate core. The 0.47 mH is 18 Ga. air core. The 0.70 mH is 20 Ga. air core. I think the 0.70 is the only one that will be really sensitive to changes - if you had something like a 15 Ga. air core or 18 Ga. laminate core, you might have to add 1/2 ohm of series resistance with it to avoid having a little peak where you don't want it.
                      Keep an open mind, but don't let your brain fall out.

                      Argon | Helium | Lithium | LithMTM | Hafnium
                      Mercury | Matrix | Shrubbery

                      Comment


                      • #12
                        Re: Lithium

                        OK, thanks, that drops about $12 vs having all air core 18 Ga.
                        what caps did you use?
                        My Statement monitors
                        My Piccolatas
                        My LM3886 amp

                        Comment


                        • #13
                          Re: Lithium

                          I just went with Dayton polypropylene caps (5% tolerance, 250V). Any entry-level poly caps should give good results. I think you could get away with non-polar electrolytic (NPE) for the 30 uF if you prefer - it would give a little more breathing room for fitting the crossover in the cabinet.

                          I can tell you from experience that anything fancier or significantly higher voltage rating than the Dayton's may give you an issue with fitting the crossover in the cabinet.
                          Keep an open mind, but don't let your brain fall out.

                          Argon | Helium | Lithium | LithMTM | Hafnium
                          Mercury | Matrix | Shrubbery

                          Comment


                          • #14
                            Re: Lithium

                            Thanks again. Now I need to finish my statement center so the wife does not complain.
                            My Statement monitors
                            My Piccolatas
                            My LM3886 amp

                            Comment


                            • #15
                              Re: Lithium

                              Scott, do you think there will be any significant difference between the Ultra Touch Denim and PE's Sonic Barrier ??

                              How thick is the Denim stuff? I have 1" Sonic Barrier on hand -- that's why I'm asking.

                              Somebody's gonna get these for Christmas from Santa
                              Bryan K.

                              Midwest Audio Club

                              Speedster | Sub Attachť | The Wildeman | Sean's NLA Towers | CO‹GAR, COUGAR II and CO‹GAR JR | Triton | Lithium | J-Boom | Trym MLTL | Docere MLTL

                              Comment

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