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  • SEOS Design questions. The motherlode.

    I've been asking questions geared around SEOS designs (and Erich H's site) a good bit lately and I really hate to keep starting a new thread with every single question. I know you guys would get sick of seeing that. I know I'd feel bad for doing it. So, I'm just gonna do a catch-all thread and ask as I go. Hopefully no one loses their cool over this. ;)

    Some questions I have (and one has been PM'd to Eric H already) that I would appreciate some input on.


    I've all but decided 100% to build a baffle wall. You probably saw my thread asking about DIY synergy horns... I've decided to scrap that idea after looking at the time of build and materials cost. My number one issue is time. I'm looking for options that allow me to cut as little wood as possible because I'll be doing enough of that as is. So, the flat packs are really looking like my best option from that perspective. Number two issue is cost. I'm going to try my best to adhere to ~$400/speaker. I want high efficiency and need response to at least 100hz. Size of the speaker isn't a concern.

    I've been considering this baffle wall option for about a year now and in that time I've researched a lot of different options. The SEOS based designs always wind up getting my attention when I come back full circle. I haven't decided if I want to use my existing electronics to go active or just K.I.S.S with a ready-made passive design which would possibly need to be powered by an AVR.

    So, I have some questions to kick this thread off.
    1) Is anyone offering a pre-cut SEOS baffle that pairs with the flat packs? ie; a baffle that houses the SEOS-12, ready to go. I thought I saw this on Eric's site once but the best I can find is a mention of it on the forums there. If this is an option, it would make it easier on me to pick and choose my drivers and go active.
    2) The "Elusive 1099"... has anyone here built it and/or compared it directly to the Tempest 12 or Sentinel 15 design? Or polars? Any thoughts here? I checked avsforum but there are SO many different threads on SEOS designs there it makes my head spin. I find myself leapfrogging from one to the other and my ADD isn't helping at all. ;)


    I'll have more. Undoubtedly. If you can help with any of the above, I'd appreciate it.

    Thanks in advance, guys.

    - Erin
    Last edited by ErinH; 11-16-2014, 09:46 PM.
    ErinsAudioCorner.com

  • #2
    Re: SEOS Design questions. The motherlode.

    Here's a post-listening party thread where the 1099 and Tempest were both present: http://www.avsforum.com/forum/89-spe...g-results.html

    Take with grains of salt of course, rooms and setups and ears are all different.

    On a side note: if you were to go ahead with a fully realized passive design in a baffle wall, I believe the Tempest already has rather full baffle step compensation and so might sound a little "thick" mounted stock in a baffle wall without some EQ to pull the lower mids and bass down a touch. The 1099 on the other hand not so much, in fact tuxedocivic has said some boundary reinforcement is a good thing for them.

    Question of my own: have you thought about toe-in and your proposed baffle wall? Many say the optimum setup for constant-directivity speakers includes an unusually strong toe-in, actually crossing in front of the main listening position. Maybe something to consider if you haven't already.

    Comment


    • #3
      Re: SEOS Design questions. The motherlode.

      Yea. I planned to toe the speakers in (curve the wall) by some degree necessary for whatever speakers I chose.

      For the baffle step, I have the ability to EQ/shelf the response if needle as well.

      I do appreciate that input though. Definitely useful things to know for the direction I'm going.
      ErinsAudioCorner.com

      Comment


      • #4
        Re: SEOS Design questions. The motherlode.

        Originally posted by antisuck View Post
        Here's a post-listening party thread where the 1099 and Tempest were both present: http://www.avsforum.com/forum/89-spe...g-results.html

        Take with grains of salt of course, rooms and setups and ears are all different.

        On a side note: if you were to go ahead with a fully realized passive design in a baffle wall, I believe the Tempest already has rather full baffle step compensation and so might sound a little "thick" mounted stock in a baffle wall without some EQ to pull the lower mids and bass down a touch. The 1099 on the other hand not so much, in fact tuxedocivic has said some boundary reinforcement is a good thing for them.

        Question of my own: have you thought about toe-in and your proposed baffle wall? Many say the optimum setup for constant-directivity speakers includes an unusually strong toe-in, actually crossing in front of the main listening position. Maybe something to consider if you haven't already.
        Yes, like with any speakers, distance and axis make a difference in the response. My measurements of the Tempest on the design axis, which incorporates a window from on axis with the tweeter to slightly above do not have that dip. If I move the mic below the tweeter axis toward the woofer then I see the dip as the crossover null begins to develop. I think in all fairness, the Tempest sounds and measures flatter than what is presented in some of the measurements in that thread.

        Regarding baffle step compensation - the Tempest has a 15" wide baffle, I really don't incorporate baffle step compensation into something like that very much. I was actually much more concerned with the hump in the response at 500 - 700 Hz due to the baffle than I was with any step. The Tempest was designed assuming some boundary reinforcement would be present as well.

        For what it's worth, Erich and I are working on a single and dual woofer 12" three-way with new custom designed woofers and a new compression driver. I am targeting some very high-end components and specs with these speakers.
        Click here for Jeff Bagby's Loudspeaker Design Software

        Comment


        • #5
          Re: SEOS Design questions. The motherlode.

          Jeff, that's really good info. Thanks for that.


          A new design? You have my attention. I'm planning to do this new build starting after the holidays. Any chance the new design would be available then or would you rather not try to estimate that?
          ErinsAudioCorner.com

          Comment


          • #6
            Re: SEOS Design questions. The motherlode.

            I've worked with a LOT of 12" drivers in the commercial field and been fortunate enough to 'try this at home' with a few, including AE. Others results may vary, but my favorite far and away for smooth response and a very be benign breakup is the RCF LF12. So if you're gonna do your own SEOS design, there's yet another 12 on the table for you. It's the closest thing to the JBL for not nearly the cost.

            Comment


            • #7
              Re: SEOS Design questions. The motherlode.

              Originally posted by ErinH View Post
              Jeff, that's really good info. Thanks for that.


              A new design? You have my attention. I'm planning to do this new build starting after the holidays. Any chance the new design would be available then or would you rather not try to estimate that?
              I just don't know at this time how soon things will be ready.
              Click here for Jeff Bagby's Loudspeaker Design Software

              Comment


              • #8
                Re: SEOS Design questions. The motherlode.

                Originally posted by Mayhem13 View Post
                It's the closest thing to the JBL for not nearly the cost.
                Which JBL in particular are you referencing?
                ErinsAudioCorner.com

                Comment


                • #9
                  Re: SEOS Design questions. The motherlode.

                  Sorry for the misinformation about the Tempest's baffle step compensation - I should know better than to repeat what I heard elsewhere, especially it being likely that Jeff himself would pop in here. At least the record has been set straight. :o

                  Comment


                  • #10
                    Re: SEOS Design questions. The motherlode.

                    Originally posted by ErinH View Post
                    Which JBL in particular are you referencing?
                    the reason I ask is because there's a cinema here that was bought out by a church. the cinema sold EVERYTHING and the church has picked some of it's keepers and is selling the rest.
                    CL ads:
                    http://huntsville.craigslist.org/ele/4748684413.html


                    I'm actually stopping by there this afternoon to look through some of what they have. I'm intrigued by the JBL 2446J and 2380A horns he has. Not sure if the horns are good but the CD's are $830/each on PE.


                    He also has a few single cabinets (which sucks, because some of the cabs were built to match up with the horns).

                    If I come across any other woofers, it would be good to know what's good and what isn't. Or, heck, if any of you guys are interested, I wouldn't mind trying to get some shipped to you if you can toss a few bucks my way.
                    ErinsAudioCorner.com

                    Comment


                    • #11
                      Re: SEOS Design questions. The motherlode.

                      Those look like 2226 woofers......an industry standard. The 2446 are also killer CDs. You could build an AMAZING baffle wall with three of each. I'd top them off with a super tweeter for flat response to 20khz.

                      What are they looking for for the three horns and double 15 cabinets?

                      Comment


                      • #12
                        Re: SEOS Design questions. The motherlode.

                        I had a look last night, and most of his "good" stuff was taken by a guy who drove down from St. Louis and dropped >$10k on some stuff including some HUGE 20"+ cabs and some elusive Altec Lansing horns.

                        So, with what he has left, he only has one of each of the following:
                        4645 (single 18)
                        4518 (single 18)
                        4639 (dual 15's) - Uses (2) 2035 HPL-1 woofers
                        4638TH (dual 15's) - Uses (2) 2035 HPL-1 woofers


                        He has (3) 2446j/2380a cd/horn combos.

                        Then he has 30 or so of the JBL 8330 (surrounds) and a lot of the 8330A surrounds.


                        IF I can get the price right, here are some of my thoughts:
                        1) Buy the dual 15" cabs and the horns. Go DIY with the 2035 drivers and the horns. The horns bother me though because, as you noted, the response may necessitate a super tweeter which I wouldn't want to have to deal with (more cost). By the time I do that I could go the SEOS route I believe.

                        2) Buy the dual 15" cabs and use the woofer to mate with a SEOS-15 waveguide and some other CD, and run active 2-way across LCR.

                        *) With either of the two above, purchase some of his surrounds at next to nothing. The efficiency is low on these compared to the fronts (90dB), but maybe that's not as big an issue.

                        3) Don't bother with any of it and continue with the other options.


                        Here's a few pics I snapped...

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                        Last edited by ErinH; 11-18-2014, 10:07 AM.
                        ErinsAudioCorner.com

                        Comment


                        • #13
                          Re: SEOS Design questions. The motherlode.

                          If you can grab a dual 15" JBL, and a pair of the compression drivers and horns, then you could make yourself a fantastic two-way from these parts. Don't underestimate the value of owning pro JBL components. These are excellent and the resale value will always be there. I would snatch these up in a heartbeat if I could.
                          Click here for Jeff Bagby's Loudspeaker Design Software

                          Comment


                          • #14
                            SEOS Design questions. The motherlode.

                            Yea. The problem is I need an LCR. I could do that if I bought both cabs (have an extra as a spare) because both of the dual 15" cabs use the same drivers and buy the 3 2446j's he has.

                            But still, the response drop above 10khz still bothers me.

                            Plus, I don't know what he'd want for all that.

                            Here's the spec sheet for the 2446j. The graph provided in there is with the 2380 horn he has with them.
                            http://www.jblpro.com/pub/components/2446.pdf
                            ErinsAudioCorner.com

                            Comment


                            • #15
                              Re: SEOS Design questions. The motherlode.

                              Originally posted by Jeff B. View Post
                              Yes, like with any speakers, distance and axis make a difference in the response. My measurements of the Tempest on the design axis, which incorporates a window from on axis with the tweeter to slightly above do not have that dip. If I move the mic below the tweeter axis toward the woofer then I see the dip as the crossover null begins to develop. I think in all fairness, the Tempest sounds and measures flatter than what is presented in some of the measurements in that thread.

                              Regarding baffle step compensation - the Tempest has a 15" wide baffle, I really don't incorporate baffle step compensation into something like that very much. I was actually much more concerned with the hump in the response at 500 - 700 Hz due to the baffle than I was with any step. The Tempest was designed assuming some boundary reinforcement would be present as well.

                              For what it's worth, Erich and I are working on a single and dual woofer 12" three-way with new custom designed woofers and a new compression driver. I am targeting some very high-end components and specs with these speakers.
                              Hmm - will you be posting this on the forums to let everyone know they're available?

                              Comment

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