Where any EMITs open back?

Discussion in 'Infinity Loudspeakers' started by goodolpg, Feb 25, 2017.

  1. goodolpg

    goodolpg AK Member Subscriber

    Asking due to a question in another part of AK.
    Were/are there any EMITs that were OEM with an open back?

    What about EMIMs?

    Thanks.
     
  2. okeeteekid

    okeeteekid Well-Known Member

    Messages:
    660
    Location:
    Northern NJ
    I don't think any of the EMIT's were open back, the only EMIM's that I know of that are open back are the High Energy ones used only in the IRS epsilon and IRS sigma, all other High Energy EMIM's had a silk cloth on the back glued to the magnets, the open back ones move more and go a little deeper in my A and B test.
     
  3. goodolpg

    goodolpg AK Member Subscriber

    Thanks, I was pretty sure I had seen open back EMIMs.
    You said "High Energy EMIM's had a silk cloth on the back glued to the magnets", does that mean they were in effect di-pole with sound coming from both the front and the back (through the silk cloth)?
     
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  4. swechsler

    swechsler Frog Whisperer

    Messages:
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    Location:
    7th row center
    AFAIK all EMIMs were open back, and no EMITs were. I know that Michael Alan Marks (the guy on eBay who sells lots of Infinity stuff at high prices) once published an article on converting two EMITs to a single dipolar EMIT, so if you see an open back EMIT, that's probably what you've got. But that procedure never made sense to me, if you want a bipolar EMIT, just wire up another one out of phase and install it on the back, just like Infinity did on so many models.
     
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  5. okeeteekid

    okeeteekid Well-Known Member

    Messages:
    660
    Location:
    Northern NJ
    Yes but infinity used foam and fiberglass on some speaker models to absorb up the back wave making the speakers mono-pole, you can read about it here. page 15 and 16, the whole artical is a good read
    https://1drv.ms/b/s!AhHWCBRVD6phd7A001XBsBP4Pbw
     
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  6. okeeteekid

    okeeteekid Well-Known Member

    Messages:
    660
    Location:
    Northern NJ
    All EMIM's are open back but with a silk clothe glued to the back magnets, the silk clothe backing controls the movement of the diaphragm better in the speakers enclosures that used them, the ones used in the IRS epsilon and sigma, not sure what the Omega has, are the only ones that are a true open back design EMIM, their speaker enclosures were designed to use the EMIM without the silk backings, here are a couple of pics, pic 1 silk backing ren 80,90 and omega?, pic 2 open back, epsilon, sigma
    IMG_2417.JPG
    s-l1600.jpg
     
    Last edited: Feb 26, 2017
  7. goodolpg

    goodolpg AK Member Subscriber

    Wow, that's some deep reading...
    thanks for the link!
     
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