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So I joined the "B2031P Club"...

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  • So I joined the "B2031P Club"...

    My wife tells me they arrived today, haven't heard them yet but I plan to when I get home from work.

    I imagine I'll open the box, poke around, take pictures...

    I'm considering:

    1) Plugging the ports (permanently) and adding a port tube on the back to reduce the minor tweeter diffraction the front ports cause.

    2) Adding "roof repair tape" bitumen + aluminum sheets to the cabinet insides for damping.

    3) Adding bracing to reduce cabinet resonce. Something like 3/4" hardwood dowel braces, I may drill 3/4" holes that align on either side, push + glue the dowel in place, trim flush, seal and paint the ends...

    4) Take raw measurements of the drivers and simulate the existing crossover in software, vaguely consider the possiblity of crossover tweeks - mostly this would just be for fun, more than any real hope of improvement.

    5) Less likely, but possibly: add 1/2" stiffening panels to the sides.

    6) Least likely: cut a new front baffle so that plugging the front ports doesn't look bad (I would use the existing tweeter waveguide, but do a more standard flush mounting of the woofer).



    Oh, BTW, I have to appologize to PE in advance, but, B&H has these suckers for only $189 per pair (including free shipping). After seeing Dan's photos of the quality woofer construction, and reading about blind listening tests of these suckers, that seems like a killer deal!

    I do still have the parts needed to build a pair of Mark's ER18DXT, so I may yet do a comparison...
    "...this is not a subwoofer" - Jeff Bagby ;)

  • #2
    Re: So I joined the "B2031P Club"...

    Where are these woofer pictures?
    I am trolling you.

    Comment


    • #3
      Re: So I joined the "B2031P Club"...

      Originally posted by MSaturn View Post
      Where are these woofer pictures?
      http://dtmblabber.blogspot.com/2010/...de-b2031p.html
      "...this is not a subwoofer" - Jeff Bagby ;)

      Comment


      • #4
        Re: So I joined the "B2031P Club"...

        Wow. Beefy.
        I am trolling you.

        Comment


        • #5
          Re: So I joined the "B2031P Club"...

          Originally posted by MSaturn View Post
          Wow. Beefy.
          A shielded design? But that is one stout looking woofer.

          1st order XO on the tweeter? There might be some beneficial mods to be made there.
          R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio
          Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

          95% of Climate Models Agree: The Observations Must be Wrong
          "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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          • #6
            Re: So I joined the "B2031P Club"...

            It is clear they spent their money saturating the gap instead of making a pretty cone. I would NOT have expected that kind of backside on such a homely girl ..
            I am trolling you.

            Comment


            • #7
              Re: So I joined the "B2031P Club"...

              A shielded design? But that is one stout looking woofer.

              1st order XO on the tweeter? There might be some beneficial mods to be made there.
              I assume you know shielding actually increases magnetic flux strength in the gap, generally yielding a small increase in efficiency.

              The woofer frame certainly does look sturdy, given it's not part of the speaker that's supposed to be visible to the consumer...

              The "knuckle rap" on the enclosure shows some room for improvement (mostly on the lower half of the sides) but these speakers weigh 25 lbs a piece and the enclosure is sturdier than many a commercial speaker I've seen (by no means equal to some of the better high end models, but better than most speakers I've seen at "big box" stores)...

              EDIT: Oh, and the waveguide around the tweeter definitely needs some damping applied to the back of it.
              "...this is not a subwoofer" - Jeff Bagby ;)

              Comment


              • #8
                Re: So I joined the "B2031P Club"...

                Critofur, it will be cool to see what mods you do and their effects.
                This post: http://dtmblabber.blogspot.com/2010/...ffraction.html has the before and after effects of stuffing the ports. I've been thinking of doing some more serious reworking of these speakers this summer and I'll be following your approach with a lot of interest. You are addressing the things I most want to. I really wish they had placed those ports elsewhere. Guess they made for a convenient cotton ball holder.

                I should add this for the picture happy http://dtmblabber.blogspot.com/2010/07/decay.html

                There's a lot of info about this speaker if you go back to the start of the blog.

                Dan
                "guitar polygamy is a satisfying and socially acceptable alternative lifestyle."~Tony Woolley
                http://dtmblabber.blogspot.com/
                http://soundcloud.com/dantheman-10

                Comment


                • #9
                  Re: So I joined the "B2031P Club"...

                  Vaguely interesting:

                  http://www.thomann.de/gb/behringer_e...fuer_b2031.htm

                  http://www.thomann.de/gb/behringer_e...uer_b2031a.htm

                  "...this is not a subwoofer" - Jeff Bagby ;)

                  Comment


                  • #10
                    Re: So I joined the "B2031P Club"...

                    Looks like SEAS OEM, perhaps.
                    I am trolling you.

                    Comment


                    • #11
                      Re: So I joined the "B2031P Club"...

                      Here's an idea: get one of those miniDSP things I somehow just discovered and make yourself the active version. heh heh.
                      I am trolling you.

                      Comment


                      • #12
                        Re: So I joined the "B2031P Club"...

                        Ugh, I hate these binding posts with the plastic rather than the knurled metal - so hard to clip aligator clips on!

                        I've got one playing with my chinsy "All-In-One Jig" test amp. I can tell it's going to need more power.

                        Even with just one speaker playing - hmm - well I'll reserve judgement until I get them properly setup in stereo. I'm thinking I might like them - I don't mean in terms of value for the $, I mean in absolute terms.

                        Initial in room measurement at moderate volume (I need an SPL meter...) measurement taken at the same height as the "Truth" logo between woofer & tweeter at ~ .85 meters:

                        "...this is not a subwoofer" - Jeff Bagby ;)

                        Comment


                        • #13
                          Re: So I joined the "B2031P Club"...

                          A shielded design? But that is one stout looking woofer.

                          1st order XO on the tweeter? There might be some beneficial mods to be made there.
                          We bought a pair of B2031A's a while back just to scavenge the amplifier modules off of them. I noticed then how ridiculously good the parts were constructed for such an inexpensive speaker. There's no way any of us could build something like this for this price, and it makes some of the "high-end" stuff that uses cheap stamped baskets and little bitty motors look really cheap.

                          We have a pair of these, essentially brand new, with drivers in cabinets, in original cartons, but with no amps or crossovers and the rear panel shows where the amp was once screwed on. I am sure my friend John would be interested in selling them if someone wanted to play around with the drivers or simply build a passive crossover of their own design for them. If you are interested, let me know.

                          Jeff B.
                          Click here for Jeff Bagby's Loudspeaker Design Software

                          Comment


                          • #14
                            Re: So I joined the "B2031P Club"...

                            Originally posted by Jeff B. View Post
                            ... I am sure my friend John would be interested in selling them if someone wanted to play around with the drivers or simply build a passive crossover of their own design for them. If you are interested, let me know.
                            Can you do much better than the $189 price at B&H??? I might rather have a 2nd pair for mucking around with rather than cutting up my only pair...

                            Originally posted by MSaturn View Post
                            Here's an idea: get one of those miniDSP things I somehow just discovered and make yourself the active version. heh heh.
                            Well you see Mr. Saturn, I got this thing called... wait for it....... a PC! ;) [Which happens to have UE and a few other crossover simulating apps]. I do want a MiniDSP for the sheer convenience, howerver.
                            "...this is not a subwoofer" - Jeff Bagby ;)

                            Comment


                            • #15
                              Re: So I joined the "B2031P Club"...

                              Originally posted by MSaturn View Post
                              Looks like SEAS OEM, perhaps.
                              They claim to roll their own, but who knows. They definitely seem to be built too well for their cost. That actually goes for the cabinets as well even though that's where the next round of mods will be made.

                              Dan
                              "guitar polygamy is a satisfying and socially acceptable alternative lifestyle."~Tony Woolley
                              http://dtmblabber.blogspot.com/
                              http://soundcloud.com/dantheman-10

                              Comment

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