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Thread: JBL EOS Waveguide Tweeter Grille

  1. #1
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    JBL EOS Waveguide Tweeter Grille




    Can anyone comment on the 'grille bars' placed across the tweeter. Is this just protection from poking fingers? The above picture is the S38II. The first Studio series (S38, S310, S312, etc.) had only one central horizintal bar across the tweet. I have seen other JBL series using EOS where one vertical bar is used. The center bar has a smallish 'cap' which cover the center of the tweeters dome. I thought I had read somewhere at one time that the center cap prevented beaming, but why the extra bars?

    Thanks, Mike Brown

  2. #2
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    EOS Waveguide

    Here's the Ti tweeter and EOS Waveguide on a PT800. One bar w/cap here.
    Attached Images Attached Images  
    Out.

  3. #3
    clmrt
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    Mapleshade's tips for better sound would have you snip those out...

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    That is precisely why I ask. If the intention was for protection of the tweets, I would not hesitate to snip them out. If their is some other purpose, well.... not sure.

  5. #5
    RIP 2011 Zilch's Avatar
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    I've seen documentation describing the purpose/utility of the contact lens.

    Damping, I think.

    Don't MAKE me find in now....

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    OK, using the phrase "contact lens" I found the following:

    http://www.jblpro.com/pub/obsolete/8325a.pdf

    It states "A unique acoustic "contact lens" is an integral part of the tweeter design. It aids in flattening the high frequency response by shadowing the center of the dome of the tweeter."

    I wonder why the second and third bars were added to the S38II, S310II, etc.?

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    Question My guess

    Quote Originally Posted by maabx
    OK, using the phrase "contact lens" I found the following:

    http://www.jblpro.com/pub/obsolete/8325a.pdf

    It states "A unique acoustic "contact lens" is an integral part of the tweeter design. It aids in flattening the high frequency response by shadowing the center of the dome of the tweeter."

    I wonder why the second and third bars were added to the S38II, S310II, etc.?
    I'd say that the extra bars are for protection. If they were a distinct design improvement, I'm guessing we'd see them on newer, more expensive models.
    Out.

  8. #8
    Administrator Mr. Widget's Avatar
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    There have been many tweeters over the years from various vendors with a dot of some sort over the center of the dome. It reduces what would otherwise be a bright sounding on axis response.

    Mapleshade... geez. Don't forget to wash the extra electrons off of your speaker cables at the end of each listening session... Mapleshade has just the soap for the task. Only $40 for enough special soap for 100 listening sessions. A bargain really...


    Widget

  9. #9
    Senior Member JBLnsince1959's Avatar
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    Quote Originally Posted by maabx
    I wonder why the second and third bars were added to the S38II, S310II, etc
    because these were sold at Best Buy and people would stick their fingers in the tweeters and screw them up.

  10. #10
    Senior Member Ian Mackenzie's Avatar
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    The device is used to correct and the otherwise problematic phase cancellation/peaking issues with domes in certain applications. Just consider why compression driver use a phase plug...

  11. #11
    Senior Member JuniorJBL's Avatar
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    Quote Originally Posted by Mr. Widget

    Mapleshade... geez. Don't forget to wash the extra electrons off of your speaker cables at the end of each listening session... Mapleshade has just the soap for the task. Only $40 for enough special soap for 100 listening sessions. A bargain really...


    Widget

    Do they carry woofer and tweeter bearings.......

  12. #12
    pelly3s
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    Quote Originally Posted by JuniorJBL
    Do they carry woofer and tweeter bearings.......

    they are expensive. they also sell a decive for reallignment of the electrons on the incoming power inorder to increase low end response in your amp

  13. #13
    RIP 2010 scott fitlin's Avatar
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    Quote Originally Posted by pelly3s
    they are expensive. they also sell a decive for reallignment of the electrons on the incoming power inorder to increase low end response in your amp
    Yes they do, that device is called a " Linear Electron Migrated Frequency Recapitulator "!

    I hear they do wonders for Bose!

    scottyj

  14. #14
    Senior Member JuniorJBL's Avatar
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    How much?

    Are the LEMFR's

  15. #15
    RIP 2010 scott fitlin's Avatar
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    Quote Originally Posted by JuniorJBL
    Are the LEMFR's
    About $1900ea!

    But, if your not snobby about brand names, and can live with not having boutique salon brand names on your audio devices, the LEMFR,s can be had for the budget price of merely a few bucks, available at your local Radio Shack, just get some " Ferrite snap on cores " for your AC cords!

    But please, dont tell everyone, as Sopranotronics is making millions selling LEMFR,s that are essentially the same as the RS ferrite cores, the only real difference between the two is the fancy " teflon " outer jacket to protect the ferrite from chipping!

    Thanks for understanding!

    scottyj

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