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Line Array in the works at Stryke Audio.

Discussion in 'Home Theater Projects' started by Brett DiMichele, Jun 25, 2003.

  1. Brett DiMichele

    Brett DiMichele Producer

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    I was talking to John tonight and he's been working more on
    his Line Array designs using the SA-RTW2 Ribbon Tweeter and
    the SA071 7" woven fiber 7" Midrange.

    John is working on a sealed version and also a vented dipole
    version. I think he will offer a group purchase on the
    drivers and xo parts in the not so distant future and I also
    think he will offer prebuilt cabinents for those who are
    unable to do thier own woodworking.

    Here is a picture of the test version dipole line array:
    [​IMG]

    Here are the links to the raw drivers:

    http://www.stryke.com/SA071.html Midrange

    and

    http://www.stryke.com/SA-RTW.html Tweeter

    I will own these babies! [​IMG]
     
  2. Brian Bunge

    Brian Bunge Producer

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    Brett,

    And from my understanding the price will be pretty sweet for the kits too![​IMG]
     
  3. Brian Bunge

    Brian Bunge Producer

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    Tim,

    Should be same as any other 2-way AFAIK.
     
  4. TimForman

    TimForman Supporting Actor

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    Do you know how the xo is designed to work? IOW, are all the drivers working in tandem or are they handling different frequency ranges?
     
  5. Brian Bunge

    Brian Bunge Producer

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    That's weird! I was responding to Tim's post, but my response is above his question.

    WILD![​IMG]
     
  6. Kyle Richardson

    Kyle Richardson Screenwriter

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    Knowing the answers before they are even asked. WOW, you really are that good.[​IMG]
     
  7. TimForman

    TimForman Supporting Actor

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    I'm impressed. Can you give me this week's winning Lottery numbers?
     
  8. Brian Bunge

    Brian Bunge Producer

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    Kyle,

    I knew you were going to say that[​IMG]

    Tim, two of the numbers are 1 and 3 (13's my favorite #). If that's not it, I must be off at the moment.
     
  9. Dave Milne

    Dave Milne Supporting Actor

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    I'm intrigued with the line array, but concerned about imaging... considering that there's no way to get equal path lengths to the listener (unless the line is curved).

    My own experience with WMTMW systems is that they are very sensitive to vertical alignment/path length. I had to tilt my speakers slightly back so that the listener's ear was precisely on-axis vertically (I did this with the help of a He-Ne laser temporarily mounted at the vertical center and perfectly perpendicular to the baffle). Once dialed in this way, the image focus is stunning; however, move your head up or down a foot and the image blurs...

    So how does the line array deal with this? Or do you just need to be far enough back that the path length difference isn't significant? Or have I missed some fundamental operating principle (quite possible)?
     
  10. CarlDais

    CarlDais Stunt Coordinator

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    Well i am not expert but I thnk you are basically correct.
    I have heard GR dsigns Line Array at DIY 2002 Texas.
    Two Line arrays in Ohio at this years MAF 2003(three actually)
    And a Pipe Dream set-up In San Jose California.
    And a few years back an older macintosh Line array.

    They all presented one helluva a life size image
    which did not exhibit pinpoint imaging
    (but pretty good imaging).
    Think very nice Maggie soundstage but greater
    dynamics....MUCH BETTER.
     
  11. Brett DiMichele

    Brett DiMichele Producer

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    Brian,

    Holy Cow you really are a peesychic! [​IMG] I knew it all along!

    Yep the price will be right! Bear in mind though that we
    are talking about 24 Mids and 24 Ribbon Tweets so there is
    some cost involved with buying this many drivers. But for
    what all you will get the price will be VERY good!

    Dave,

    Carl hit the nail on the head as did you.. Yes the perfect
    setup would employ a curved baffle but for most diy deals
    that's far to complex. These things should cast one hell of
    a huge sound stage, it may not be as pinpoint accurate as
    say an MTM or an TM but will have a far broader stage and
    more of an openess to them. Every speaker has it's drawbacks
    and it's positives. I think the positives will far outweight
    it's design limitaions [​IMG]

    Tim,

    I am not sure yet what John is doing for the XO's we talked
    last night and there are just so many ways these things can
    be built.. He was thinking about doing the test sealed
    version tuned somewhere in the 38Hz region I would imagine
    that is using all of the mids to acheive the low end response
    not just some of the drivers. That's one of the reasons for
    using so many drivers because that 12 mids can play with
    more dynamics than one or two and coupled they can play low
    cleanly.

    I am sure these could be active also (that would get a bit
    tricky though..)

    More details will be presented as I find out about them.
     
  12. Chuck Bogie

    Chuck Bogie Second Unit

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    Uh... Stupid question here, but aren't you going to need to cross 'em a lot lower than 2,500, or you're going to have problems with comb filtering from the woofs being mounted on 7" center/center? In an array I've been researching (prior to building), I'm going to have to cut at approx 3,300 with my woofs on 4" centers.

    Or I've _really_ misunderstood what some folks have told me...
     
  13. Patrick Sun

    Patrick Sun Moderator
    Moderator

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    Y'all didn't know that Brian's middle name was "Karnac"?
     
  14. John E Janowitz

    John E Janowitz Second Unit

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    Wow, lots of interest here. Guess I can give a little more of the details on what's going on here. I'll go through the basics here first. Each line will use 12 of the SA071 and 12 RTW2. This line can be done either as a sealed or vented design. The enclosure size will be 88" tall, 16" wide and 12" deep. The enclosure design calls for a 2" roundover on the vertical edges. This helps with diffraction much more than just a 3/4" or 1" roundover would, and IMO looks very cool when wrapped with veneer.

    The sealed design will have an F3 point of about 70hz, with an F6 around 50hz. The sealed design is intended to be crossed to a seperate subwoofer between 50-70hz.

    The vented design can be tuned to about 30hz. This gives an F3 point of about 49hz, but a very shelfed off low end that will work well with room gain. The F10 point is about 24hz. In some situations this would work very well without the need for an added subwoofer.

    The Xover is realy not as complicated as you would think. It is very similar to a standard 2way Xover. The xover point still needs to be determined yet. According to what I have seen, the half wavelength point is the absolute highest frequency before comb effects begin to be evident. Standard 6.5" drivers placed 6.5" apart (a wavelength of 2086
    Hz) start losing their directivity above that frequency and exhibit audible and measurable comb lines starting at 4172Hz. Ideally you would want to cross at 2086hz or lower, but raising the Xover frequency slightly is still possible.

    I will be doing extensive measurements to make sure that the Xover frequency is low enough so that the comb effects are not evident. I will place the microphone at 1m, 2m, and 3m from the line array. Then I will take 7 measurements, each moving the mic up 1" at a time. Overlaying these plots will clearly show where the comb effects become evident. From my quick measurements when I played with the dipole a little, I can go up to about 3200-3300hz before there is any deviation more than about .5dB. Xover will most likely take place at 2700hz, assuring there is no problem with come effects with the woofer line. I will post all the measurements and overlaid plots for everyone to see exactly what is going on here.

    Dave, as far as imaging goes, everyone I have played the other line arrays for was blown away by the imaging. In ideal line array works creating a cylindrical wavelaunch. Think instead of a point source playing out to all directions, a large cylinder moving towards you. This greatly controls the early reflections off the floor and ceiling. Yes there would be a different path length from say the top mid to your ear and the middle mid to your ear. However, compare this to a point source. The path length from the point source to the ceiling and back down to you is much longer than the path length from the point source directly to you.

    As far as the rest of the vertical alignment goes, as long as you are within the array's vertical span, sound should be almost the same at all heights. That is one reason I like line arrays so much. If you sit down or stand up, they still sound nearly the same. The soundstage is extremely large. I had a pair setup in a somewhat large room playing the Eagles Hell Freezes over live cd and someone commented to me that when he closed his eyes he thought he was at a concert. :)

    Other benefits are high sensitivity. The line will be between 92-95dB. This depends on the amount of baffle step correction used to bring up the low end. Distortion is extremely low since each driver has to do only 1/12 the work that a single driver would to get the same output levels.

    I should have some more details to give tomorrow.

    John
     
  15. Brett DiMichele

    Brett DiMichele Producer

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    The boss has spoken!

    John,

    Thanks for providing the info!

    They are going to be sweet [​IMG]
     
  16. John Wes

    John Wes Stunt Coordinator

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    Awsome.......Not more I could add than that!
     
  17. Brett DiMichele

    Brett DiMichele Producer

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    I just wish someday I could be as smart as John, ThomasW,
    Jon Marsh, Patrick Sun, Dan Westor and many others... [​IMG]

    We sure have a bunch of sharp tacks here on the HTF and it's
    a good thing we do!
     
  18. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I heard something about a concave or curved line array...

    This intrigues me in that I'll have to consult my scandinavian cabinet builder on how we can make one. [​IMG] This job i'm working on might provide some spare cash... What's the estimate on all drivers and XOs? $1400?

    Would there need to be any XO adjustments if the baffle was designed just like the one above, only curved to make the drivers equal distant from the listener?
     
  19. Kyle Richardson

    Kyle Richardson Screenwriter

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    The matching center channel to these arrays will be curved so the voices will image correctly. Dont know if that is what you were thinking of.
     
  20. Chris Tsutsui

    Chris Tsutsui Screenwriter

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