Malcolm, a SEOS12 Center (Middle?) Channel speaker

Discussion in 'DIY Speakers and Subwoofers' started by BillWaslo, Mar 31, 2012.

  1. I'd go with something like the Daniel design. Can be small and good performance, and already worked out.
  2. Thanks for the reply bwaslo. One point though on my comment about the Everest's...I was talking about how the two woofers are angled away from one another, not the midrange horn. Sorry if I wasn't clear enough on that point.

    IIRC, that angled baffle bit for the woofers is similar to Vance Dickason's 'ideal' center channel design in the LDCB.
  3. Oh, sorry I misunderstood. I think you could angle the woofers out if you wanted, but that would put the waveguide jutting out above the woofers as a reflecting surface, or the horn recessed back behind the woofers' plane. Not sure it would gain anything, but who knows?

    I've wanted to play with two 90degree horns angled out like that to give 180 coverage above a small woofer in a box against the wall (which would also be 180 already), that would give the best coverage for rear channel without bouncing too much stuff off the ceiling.
  4. Can a design like the Malcom be done active? Maybe an active/passive hybrid to handle the "shading"? Did you ever try it that way Bill?
  5. Never tried it but there's no reasons it shouldn't work.
  6. More questions about Malcolm. If you can't tell, I really like your design. :)

    What kind of efficiency did you end up getting out of the final speaker?

    What did the complete speaker weigh? I'm thinking about mounting options above a display.

    Any particular reason you measured it with the horn above the woofers? It seems like if placed above a display the speaker will most often be a little on the high side. Flipping it over should minimize the vertical off axis angle, if the speaker's sitting flat. Does the bass reinforcement of the screen that you mentioned not work so well if it's flipped?
  7. Right, the woofers near the screen help the bass a little. Though that could easily handled by EQ (Audessey, etc).

    If you have room, the Big, Mal would play louder, higher efficiency and cost less (buyout woofers) not much weight difference (neo woofers). But its not tiny...

    Sensitivity of these designs should be about 6dB (maybe a dB less from crossover) above the sensitivity of a single woofer. Big Mal would be about 94dB. Malcolm should be about 89dB.
  8. Kudo's Bill-

    Bit by bit here I'm absorbing how this constant directivity stuff works and your approach here is fascinating me. I bought the seos-18's and BA-750's from the classifieds and after limited testing the idea of extending the horizontal directivity much lower has a lot of appeal for L and R speakers with the crossfireing toe-in in my application.

    So if I understand the XO (which I don't) the cap on the outside woofers is a low pass filter and wherever it's corner frequency is, is the place at which the shaded array maintains horizontal directivity? I'm curious how I might scale this concept up a bit to seos-18 and larger woofers and achieve the horizontal directivity down to ideally 150hz or so.
  9. OK I got fancy and used the google. Very interesting.

    What about combining a seos with a CBT setup like this, and as I understand only the outside woofers would be attenuated enough to create the constant beamwidth. Or would the outside woofers be too far away from the center of the WG?

    Attached Files:

  10. Bwaslo

    I'm a little late in the game, so I apologize for that. I am building a set LCRs that will use an 18" SEOS with a B&C 250, and two B&C neo woofers. I would prefer this to be very high efficiency design, likely around 100db. The woofers are aprox 99db each.

    My delema is as follows. I definately want a 3 way. My first design idea was going to use a SEOS 24 with a Radian 951 driver crossed about 500hz low and a SEOS 12 crossed higher atbaround 1200h with the 250 CD to bypass the breakup of the Radian. This very pricey.

    Another option is to use Parhams midhorn, which is driven by a Delta 10. This option is definitely cheaper.

    My third option is to use the Aura NS6 I have quite a few of and do two rows of four with the outer two shaded lower in frequency, like the Malcom. I am very concerned about achwiving directivity as low as I can maintain it. I can do 4 way active for all three mains. I can do 4 Auras above and below the waveguide, thought this may help vertical directivity or I can do all below. This is the cheapest option as I have all the equipment. Just not sure how to handle two rows of Auras. Or If I need them for 100 db efficiency.

    Last option is do 8s below the SEOS like the current SEOS design or 8s above and below. I have a few woofers in mind, but they only need a bandwidth of approx 200 - 300 htz to about 1000 to 1200htz.

    In really don't have much experience with multiple drivers running the same frequencies as far as controlled directivity goes, hence my call for help.

    Also with whatever Auras I have left I will likely go with and established surround design, but that is for later.

    Thanks in advance.

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